Answer:
CaAsHO₄
Explanation:
The data has a mistake in one of the values there. I believe the mistake is on the hydrogen. So, I'm going to assume the value of Hydrogen is 0.6%, so the total percent composition would be 100.1% (Something better). All you have to do is replace the correct value of H (or the value with the mistaken option) and do the same procedure.
Now, to calculate the empirical formula, we can do this in three steps.
Step 1. Calculate the amount in moles of each element.
In these case, we just divide the percent composition with the molar mass of each one of them:
Ca: 22.3 / 40.078 = 0.5564
As: 41.6 / 74.9216 = 0.5552
O: 35.6 / 15.9994 = 2.2251
H: 0.6 / 1.00794 = 0.5953
Now that we have done this, let's calculate the ratio of mole of each of them. This is doing dividing the smallest number of mole between each of the moles there. In this case, the moles of As are the smallest so:
Ca: 0.5564/0.5552 = 1.0022
As: 0.5552/0.5552 = 1
O: 2.2251/0.5552 = 4.0077
H: 0.5953/0.5552 = 1.0722
Now, we round those numbers, and that will give us the number of atoms of each element in the empirical formula
Step 3. Write the empirical formula with the rounded numbers obtained
In this case we will have:
Ca: 1
As: 1
O: 4
H: 1
The empirical formula would have to be:
CaAsHO₄
Two different compounds are obtained by combining nitrogen with oxygen. The first compound results from combining 46.7 gg of NN with 53.3 gg of OO, and the second compound results from combining 17.9 gg of NN and 82.0 gg of OO. Calculate the ratio of the mass ratio of OO to NN in the second compound to the mass ratio of OO to NN in the first compound.
Answer:
4.02
Explanation:
The mass ratios will be given by dividing the mass of O₂ into the mass of N₂.
So lets do our calculations:
First Compound:
53.3 g O₂ / 46.7 g N₂ = 1.14
Second Compound:
82.0 g O₂ / 17.9 g N₂ = 4.58
Ratio = 4.58 / 1.14 = 4.02
This result for all practical purposes is a whole number, and it is telling us that there are 4 times as many oxygen atoms in the second coumpound as in the first compound. This is so because the ratio we just calculated is also the ratio in mol atoms:
Ratio = [ mass O₂ / MW O2/ mass N₂/ MW N₂] 2nd compound / [mass O₂ / MW O2/ mass N₂/ MW N₂ !st compound]
and the molecular weights cancel each other.
The only N and O compounds that follow this ratio are N₂O₄ and N₂O, and this question could be made in a multiple choice to match formulas.
Answer: 2
Explanation:
Two different compounds are obtained by combining nitrogen with oxygen. The first compound results from combining 46.7 g of N with 53.3 g of O, and the second compound results from combining 30.4 g of N and 69.6 g of O. Calculate the ratio of the mass ratio of O to N in the second compound to the mass ratio of O to N in the first compound.
2
The ratio of the mass ratio of O to N in the second compound to the mass ratio of O to N in the first compound is calculated as
mass of Omass of N in second compound ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯mass of Omass of N in first compound = 2.291.14 = 2
Thus, the mass ratio of O to N in the second compound is two times the mass ratio of O to N in the first compound.
Whay is it important for a forensic scientist to have as much information as possible about the place where a possible drug substance was found?
Answer: it is important because the location of crime tells a lot about possible substances that may have been in the area, may affect the drug substance in question, thus helping in tracking location other substances, why they are there, who used or placed them, assisting you in resolving a scene of crime
Explanation:
How did the growth of ideals of mass democracy, including such concerns as expanding suffrage, public education, abolitionism, and care for the needy affect political life and discourse?
It had an impact on democratically incompatible systems, and it forced people to address those problems.
What is democracy?Democracy is defined as a system of government where the populace has the power to decide legislation and debate issues. Supporting democracy helps build a more safe, stable, and affluent global environment where the United States may advance its national interests in addition to advancing such core American principles as worker rights and freedom of religion.
Democratically incompatible system is defined as a type of government where the people themselves hold the ultimate power and exercise it either directly or indirectly through a system of representation that often includes regular free elections. Democracy that is guided by a constitution. Deliberative democracy is a system in which the key to making moral decisions is real deliberation, not just voting.
Thus, it had an impact on democratically incompatible systems, and it forced people to address those problems.
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Draw a structure for an amine that exhibits a molecular ion at M+ = 87 and that produces fragments at m/z = 72 and m/z = 58.
Answer:
The amine is N-methylbutan-2-amine and the structure is drawn below.
Explanation:
In order to find out the correct structure for said data we will first try out to find the molecular formula by applying rule of thirteen.
Rule of Thirteen:
First divide the parent peak value by 13 as,
= 87 ÷ 13
= 6.6923
Now, multiply 13 by 6,
= 13 × 6 (here, 6 specifies number of carbon atoms)
= 78
Now subtract 78 from 87,
= 87 - 78
= 9
Add 9 into 11,
= 9 + 6
= 15 (hydrogen atoms)
So, the rough formula we have is,
C₆H₁₅
Now, add one Nitrogen atom to above formula and subtract one Carbon and 2 Hydrogen atoms as these numbers are equal to atomic mass of Nitrogen atom as,
C₆H₁₅ -------N--------> C₅H₁₃N
Hence, the molecular formula is C₅H₁₃N.
The correct structural formula is being predicted by using the stability of the fragments formed by the cleavage of the parent molecule. Therefore, as shown below, following secondary (stable) carbocations are formed as the major fragments.
A solution is made by mixing 36. g of heptane (C_7H_16) and 16. g of chloroform (CHCl_3). Calculate the mole fraction of heptane in this sol'. Be sure your answer has the correct number of significant digits.
Answer:
Mole fraction of solute (heptane) → 0.73
Explanation:
Mole fraction = Moles of solute or solvent / Total moles
Let's calculate the moles of everything:
Moles of solute → Mass of solute / Molar mass
36 g / 100 g/mol = 0.36 moles
Moles of solvent → Mass of solvent / Molar mass
16 g / 119.35 g/mol = 0.134 moles
Total moles = 0.36 + 0.134 = 0.494 moles
Mole fraction of solute = 0.36 / 0.494 → 0.73
hcl A solution of sodium thiosulfate (Na2S2O3) in water is 12.00 % sodium thiosulfate by mass. Its density is 1.1003 g cm-3 at 20 °C. Compute its molarity, mole fraction, and molality at this temperature.
Answer:
[Na₂S₂O₃] = 0.83 M
[Na₂S₂O₃] = 0.86 m
Mole fraction = 0.015
Explanation:
Na₂S₂O₃ 12 % by mass. This data means, that 12 g of solute are contained in 100 g of solution.
Let's find out the volume of solution, with density to determine molarity.
Solution density = Solution mass / Solution volume
1.1003 g/cm³ = 100 g / Solution volume
100 g / 1.1003 g/cm³ = Solution volume → 90.88 mL (1cm³ = 1mL)
Now, that we have volume, we can calculate molarity
Molarity is mol/L
90.88 mL = 0.09088 L
12 g / 158.12 g/mol = 0.0759 moles
0.0759 moles / 0.09088 L = 0.83 M
Total mass of solution = 100 g
12 g + Solvent mass = 100 g
Solvent mass = 100 g - 12 g → 88 g
Molality = moles of solute /1kgof solvent
88 g = 0.088 kg
0.0759 moles / 0.088 kg = 0.86 m
As solvent mass is 88 g, let's determine solvent's moles for mole fraction
88 g / 18 g/mol = 4.89 moles
Mole fraction = moles of solute / moles of solutes + moles of solvent
Mole fraction = 0.0759 mol / 0.0759 mol + 4.89 moles = 0.015
Consider the chemical reaction :
????????H4 + ????????2 → c????????2 + ????H2????,
where ????, ????, c, and ???? are unknown positive integers. The reaction must be balanced; that is, the number of atoms of each element must be the same before and after the reaction. For example, because the number of oxygen atoms must remain the same, 2????=2c+????. While there are many possible choices for ????, ????, c, and ???? that balance the reaction, it is customary to use the smallest possible integers.
Balance this reaction.
The question is incomplete, here is the complete question:
Consider the chemical reaction:
[tex]aCH_4+bO_2\rightarrow cCO_2+dH_2O[/tex]
where a, b, c, and d are unknown positive integers. The reaction must be balanced; that is, the number of atoms of each element must be the same before and after the reaction. For example, because the number of oxygen atoms must remain the same, 2b=2c+d. While there are many possible choices for a, b, c, and d that balance the reaction, it is customary to use the smallest possible integers.
Balance this reaction.
Answer: The value of a, b, c and d in the given chemical equation are 1, 2, 1 and 2 respectively.
Explanation:
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
For the given chemical reaction:
[tex]aCH_4+bO_2\rightarrow cCO_2+dH_2O[/tex]
On reactant side:
Number of carbon atoms = 1
Number of hydrogen atoms = 4
Number of oxygen atoms = 2
On product side:
Number of carbon atoms = 1
Number of hydrogen atoms = 2
Number of oxygen atoms = 3
We need to balance the number of hydrogen and oxygen atoms. So, the balanced equation for the given reaction becomes:
[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]
Hence, the value of a, b, c and d in the given chemical equation are 1, 2, 1 and 2 respectively.
As an EPA scientist studying catalytic converters and urban smog, you want to find Kc for the following reaction: 2 NO2 (g) ⇋ N2(g) + 2 O2(g) Kc = ?? Use the following data to find the unknown Kc:
1/2 N2 (g) + 1/2 O2 (g) ⇋ NO (g) Kc = 0.004
2NO2 (g) ⇋ 2NO (g) + O2 (g) Kc = 0.056
Answer:
3500
Explanation:
The equilibrium constant of the reaction which has to be calculated is:-
2 NO2 (g) ⇋ N2(g) + 2 O2(g)
The given chemical equation follows:
1/2 N2 (g) + 1/2 O2 (g) ⇋ NO (g)
The equilibrium constant for the above equation is 0.004.
We need to calculate the equilibrium constant for the reverse equation of above chemical equation and also double of the above chemical equation, which is:
2NO (g) ⇋ N2 (g) + O2 (g)
The equilibrium constant for the reverse double reaction will be the reciprocal of the initial reaction.
If the equation is multiplied by a factor of '2', the equilibrium constant of the reverse reaction will be the square of the equilibrium constant of initial reaction.
The value of equilibrium constant for reverse reaction is:
[tex]K_{eq}'=(\frac{1}{0.004})^2[/tex] = 62500
The given chemical equation follows:
2NO2 (g) ⇋ 2NO (g) + O2 (g)
The equilibrium constant for the above equation is 0.056.
Thus, adding the both reaction gives the original reaction. So, equilibrium constant is:- 62500 x 0.056 = 3500
Final answer:
By manipulating and combining the equilibrium constants of related reactions, we find that the Kc for the reaction 2 NO2 (g) ⇋ N2(g) + 2 O2(g) is approximately 3500.
Explanation:
To calculate the equilibrium constant Kc for the reaction 2 NO2 (g) ⇌ N2(g) + 2 O2(g), we need to relate it to the known Kc values of the related reactions:
1/2 N2 (g) + 1/2 O2 (g) ⇌ NO (g), Kc = 0.0042NO2 (g) ⇌ 2NO (g) + O2 (g), Kc = 0.056To find the Kc for the desired reaction, we use the concept of reaction quotients, where the product of the equilibrium constants of two related reactions that gives the target reaction when added together, equals the equilibrium constant of the target reaction. Mathematically, if the second reaction is reversed, its Kc is inverted. Then we can combine the two equations:
The equilibrium constant for the reverse double reaction will be the reciprocal of the initial reaction.
If the equation is multiplied by a factor of '2', the equilibrium constant of the reverse reaction will be the square of the equilibrium constant of initial reaction.
The value of equilibrium constant for reverse reaction is
K_(eq)'=((1)/(0.004))^2 = 62500
The given chemical equation follows:
2NO2 (g) ⇋ 2NO (g) + O2 (g)
The equilibrium constant for the above equation is 0.056.
Thus, adding the both reaction gives the original reaction. So, equilibrium constant is:- 62500 x 0.056 = 3500
A chemist added an excess of sodium sulfate to a solution of a soluble barium compound to precipitate all of the barium ions as barium sulfate, BaSO4. How many grams of barium ions are in a 441-mg sample of the barium compound if a solution of the sample gave 403 mg BaSO4 precipitate? What is the mass percentage of barium compound?
Answer:
259.497 mg, 58.84%
Explanation:
BaSO₄ → Ba²⁺ + SO₄²⁻
to calculate the mole of BaSO₄
mole BaSO₄ = mass given / molar mass = 403 mg / 233.38 g/mol = 1.7268 mol
comparing the mole ratio
1.7268 mol of BaSO₄ yields 1.7268 mol of Ba²⁺
403 mg BaSO₄ yields ( 1.7268 × 137.327 ) where 137.327 is the molar mass of Barium mol of Ba²⁺
441 mg BaSO₄ will yield ( 1.7268 × 137.327 × 441 mg ) / 403 mg = 259 .497 mg
mas percentage of the Barium compound = 259 .497 mg / 441 mg × 100 = 58.84%
"What does this observation tell us about the enthalpy of C2H5Cl(g) as compared with the enthalpy of C2H5Cl(l)
Answer:
Enthalpy of gas is greater than that of liquid
Explanation
Ethyl chloride (C2H5Cl) boils at 12 degrees Celsius. When liquid C2H5Cl under pressure is sprayed on a room-temperature (25 degrees Celsius) surface in the air, the surface is cooled considerably.
this preamble could precede the question
Enthalpy
it can defined as the ability of a substance to change at constant pressure, enthalpy tells how much heat and work was added or removed from the substance. Enthalpy is similar to energy, but not the same. When a substance grows or shrinks, energy is used up or released.
The total heat content of a system is known as Enthalp.it is a thermodynamic property. It is the internal energy of the system plus the product of pressure and volume.
H=U+PV........................1
A student heats 2.796g of zinc powder with 2.414g of sulphur.He reported that he obtained 4.169g of zinc sulfide and recover 1.041g of unreacted sulfur.
Show by calculation whether or not his results obey the law of conversation of mass
Answer:
The mass of reactants and products are equal hence the reaction obeys law of conservation of mass
Explanation:
The law of mass conservation states that for a closed system to all transfer of mass, the mass of system must remain constant over time. This means for a chemical reaction, the mass of reactants must equal the mass of products.
if 2.796g of Zn reacts with 2.414g of sulphur to produce 4.169g of ZnS ad 1.041g of unreacted sulphur, then it means that accorfing to the law of mass conservation, the mass of reactants (zinc and sulphur), must be equal to mass of products (zinc sulfide and unreacted sulphur)
Mass of reactants = 2.796g + 2.414g =5.21g
Mass of products = 4.169g + 1.041g=5.21g
In accordance with the Law of Conservation of Mass, the total mass of the reactants (5.21g) is equal to the total mass of the products (5.21g). Therefore, the student's results obey the Law of Conservation of Mass.
Explanation:The Law of Conservation of Mass states that matter can neither be created nor destroyed. Therefore, the total mass of the reactants should be equal to the total mass of the products in a chemical reaction.
Let's add up the mass of the reactants:
Zinc: 2.796gSulphur: 2.414gTotal mass of reactants = 2.796g + 2.414g = 5.21g
Now, let's add up the mass of the products:
Zinc sulfide: 4.169gUnreacted sulphur: 1.041gTotal mass of products = 4.169g + 1.041g = 5.21g
As we can see, the total mass of the reactants is indeed equal to the total mass of the products. Thus, the student's results obey the Law of Conservation of Mass.
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Which compound (s) has(have) a molecular ion at 117 and a peak at 1720 cm-1 in its IR spectrum?
Answer:
Ethyl Acetate with a chemical configuration of : CH3CO2CH2CH3
Explanation:
Ethyl Acetate has a density of 902 kg/m³, molar mass of 88.11 g/mol and posses a boiling point of 77.1 °C.
It is to be understood that ethyl acetate is the ester of ethanol and it is mostly produced in mass production and most especially used in the production of domestic materials especially materials like glue, efostics and dissolving agent. This is a highly toxic and flammable substance. However colorless and possess a sweet smell, it can be highly poisonous when ingested.
Chlorine is the most widely used disinfectant for killing pathogens during water treatment. Determine the kilograms of chlorine used daily at a water treatment plant handling 10,000 cubic meters per day of flow at a chlorine dosage of 10 mg/L. [Hint: Multiply the flow rate by the chlorine dosage and make appropriate conversions.] Ans
Explanation:
The given data is as follows.
Flow of chlorine (Q) = [tex]10,000 m^{3}/day[/tex]
Amount of liter present per day is as follows.
[tex]10,000 \times 10^{3} l/day[/tex]
It is given that dosage of chlorine will be as follows.
10 mg/l = [tex]10 \times 10^{-6}[/tex] kg/l
Therefore, total chlorine requirement is as follows.
Total chlorine requirement = [tex](10,000 \times 10^{3}) \times (10 \times 10^{-6})[/tex] kg/day
= 100 kg/day
Thus, we can conclude that the kilograms of chlorine used daily at the given water treatment plant is 100 kg/day.
Phosphorus is obtained primarily from ores containing calcium phosphate.
If a particular ore contains 53.1% calcium phosphate, what minimum mass of the ore must be processed to obtain 3.57 kg of phosphorus?
Answer:
33.7 kg
Explanation:
Let's consider calcium phosphate Ca₃(PO₄)₂.
The molar mass of Ca₃(PO₄)₂ is 310.18 g/mol and the molar mass of P is 30.97 g/mol. In 1 mole of Ca₃(PO₄)₂ (310.18 g) there are 2 × 30.97 g = 61.94 g of P. The mass of Ca₃(PO₄)₂ that contains 3.57 kg (3.57 × 10³ g) of P is:
3.57 × 10³ g × (310.18 g Ca₃(PO₄)₂/61.94 g P) = 1.79 × 10⁴ g Ca₃(PO₄)₂
A particular ore contains 53.1% calcium phosphate. The mass of the ore that contains 1.79 × 10⁴ g of Ca₃(PO₄)₂ is:
1.79 × 10⁴ g Ca₃(PO₄)₂ × (100 g Ore/ 53.1 g Ca₃(PO₄)₂) = 3.37 × 10⁴ g Ore = 33.7 kg Ore
a. Determine the sign of the charge on each rod.
b.Compute the ratio of the linear charge densities on the two rods, .
Answer.
The electric field due to a negative charge points radially in from all directions (because a positive test charge placed near it would feel a force pointing toward it). Generally, electric field lines always point from positive charges and toward negative charges.
Your question I s incomplete, please endeavor you update your question with the necessary parameters.
An aluminum atom has a mass of 4.48 * 10-23 g and a small airplane has a mass of 5000 kg. Use this information to answer the questions below. Be sure your answers have the correct number of significant digits.(a) What is the mass of 1 mole of aluminum atoms?(b) How many moles of aluminum atoms have a mass equal to the mass of a small airplane?
Answer:
a. 27g/mol
b. 1.85 x 10^5 moles
Explanation:Please see attachment for explanation
A student needs to convert a volume of 3 Tbsp (tablespoons) to mL. The student finds out that 1 tablespoon is equivalent to 14.79 mL. Choose the correct numbers and units that must be found in the conversion factor to solve this problem.
Answer:
The conversion factor is 14.79 mL/Tbsp.
Explanation:
To do an unity conversiton, we can make a factor by a ratio transformation:
[tex]3 Tbsp * \frac{14.79 mL}{1Tbsp}[/tex]
So, the conversion factor is 14.79 mL/Tbsp and 3 Tbsp has 44.37 mL.
The conversion factor of the tablespoon to volume has been 14.79mL/tablespoon.
Conversion factor has been defined as the unit that has been used to convert one unit range to another.
The computation with the conversion factor has been used in the system for the calculations and transform in the reactions.
Conversion factor for tablespoon to mLThe estimated value of 1 tablespoon has been found to be 14.79 mL. The conversion of 3 tablespoons to mL has been given as:
[tex]\rm 1\;tablespoons=14.79 \;mL\\3\;table spoons=3\;\times\;14.79 \;mL\\3\;tablespoons=44.37\;mL[/tex]
The volume of 3 tablespoon solution has been 44.37 mL.
The conversion has been performed with 1 tablespoon equivalent to 14.79 mL.
Thus, the conversion factor of the tablespoon to volume has been 14.79mL/tablespoon.
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Suppose 2.19g of barium acetate is dissolved of 15oml barium of a 0.10M acetate is dissolved in of a aqueous solution of sodium chromate. Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the barium acetate is dissolved in it. Be sure your answer has the correct number of significant digits.
The question is incomplete, here is the complete question:
Suppose 2.19 g of barium acetate is dissolved in 150 mL of a 0.10M of aqueous solution of sodium chromate. Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the barium acetate is dissolved in it. Be sure your answer has the correct number of significant digits.
Answer: The final molarity of acetate ion in the solution is 0.12 M
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}[/tex] .....(1)
For Sodium chromate:Molarity of sodium chromate solution = 0.10 M
Volume of solution = 150 mL
Putting values in equation 1, we get:
[tex]0.10M=\frac{\text{Moles of sodium chromate}\times 1000}{150}\\\\\text{Moles of sodium chromate}=\frac{(0.10\times 150)}{1000}=0.015mol[/tex]
For barium acetate:To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of barium acetate = 2.19 g
Molar mass of barium acetate = 255.43 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of barium acetate}=\frac{2.19g}{255.43g/mol}=0.0086mol[/tex]
The chemical equation for the reaction of barium acetate and sodium chromate follows:
[tex]Ba(CH_3CO_2)_2+Na_2CrO_4\rightarrow BaCrO_4(s)+2Na^+(aq.)+2CH_3CO_2^-(aq.)[/tex]
By stoichiometry of the reaction:
1 mole of barium acetate reacts with 1 mole of sodium chromate
So, 0.0086 moles of barium acetate will react with = [tex]\frac{1}{1}\times 0.0086mol[/tex] of sodium chromate
As, given amount of sodium chromate is more than the required amount. So, it is considered as an excess reagent.
Thus, barium acetate is considered as a limiting reagent because it limits the formation of product.
By Stoichiometry of the reaction:
1 mole of barium acetate produces 2 moles of acetate ions
So, 0.0086 moles of barium acetate will produce = [tex]\frac{2}{1}\times 0.0086=0.0172mol[/tex] of acetate ion
Now, calculating the molarity of acetate ions in the solution by using equation 1:
Moles of acetate ion = 0.0172 moles
Volume of solution = 150 mL
Putting values in equation 1, we get:
[tex]\text{Molarity of acetate ions}=\frac{0.0172\times 1000}{150}\\\\\text{Molarity of acetate ions}=0.12M[/tex]
Hence, the final molarity of acetate ion in the solution is 0.12 M
Calculate the percent error of your average specific heat as compared to the accepted values listed.Report your answer to the correct number of significant figures. This may be 2 or 3 significant figures. Csp(Pb) = 0.128 J/goC; Csp(Al) = 0.900 J/goC; Csp(Cu) = 0.387 J/goC % Error =
Answer:
%Error for Al = 2.23
%Error for Cu=2.65
%Error for Pb= 1.59
Explanation:
Percentage error is the difference between a measured value and a true value as expressed in percent.
%Error =( True value - measured value )/True value ×100
If the measured value is less than true value
%Error = ( Measured value - True value) / True value × 100
If the measured value is greater than true value
For Pb, true value = 0.126J/g•C
Measured value =0.128J/g•C
%Error= (0.128-0.126)/0.126 ×100= 1.57
For Cu, true value = 0.377J/g•C
Measured value = 0.387J/g•C
%Error = (0.387-0.377)/0.377 ×100 =2.65
For Al, True value = 0.921J/g•C
Measured value = 0.900J/g•C
%Error= (0.921-0.900)/0.921 ×100 =2.23
The proper solvent choice is crucial for effective recrystallization.
What are the features of a good recrystallization solvent?
a)The solvent should dissolve a moderate quantity of the target substance near its boiling point but only a small quantity near 0 °C.
b)The solvent should not react with the target substance.
c)The crude compound should be soluble in this solvent at room temperature.
d)The solvent should be easily removed from the purified product.
e)The solvent should have a high boiling point.
Answer: option A. The solvent should dissolve a moderate quantity of the target substance near its boiling point but only a small quantity near 0 °C
Explanation:
Final answer:
A good recrystallization solvent should dissolve the substance near its boiling point but not at low temperatures, must not react with the substance, should be easily removed post-process, and ideally, should have a low boiling point to prevent 'oiling out'.
Explanation:
Features of a Good Recrystallization Solvent
The process of recrystallization is integral to purifying solid compounds in chemistry, and the choice of solvent is critical for its success. A good recrystallization solvent should have the following features:
The solvent should dissolve a significant quantity of the target substance near its boiling point and only a minimal quantity near 0 °C, allowing for recrystallization upon cooling.The solvent should not react with the target substance, thereby preventing chemical changes during the process.The crude compound should be insoluble in the solvent at room temperature; this ensures that the compound remains undissolved until heated.Following the recrystallization, the solvent should be easily removed from the purified product, typically via evaporation due to its relatively low boiling point.While a high boiling point is not ideal, the solvent's boiling point should be sufficient to dissolve the substance when heated.Additionally, ideal solvents are usually unreactive, inexpensive, and have low toxicity. Using a solvent with a relatively low boiling point is preferable as it reduces the chance of the compound 'oiling out' during the process, which can interfere with crystal formation. Mixed solvents can be used when no single solvent meets all criteria, though a single solvent is often best to maintain consistent solubility conditions.
Which of the following aqueous solutions contains the greatest number of ions?
a. 400. mL of 0.10 M NaCl;
b. 300. mL of 0.10 M CaCl2;
c. 200. mL of 0.10 M FeCl3
Answer : The correct option is, (b) 300. mL of 0.10 M CaCl₂
Explanation :
We have to calculate the number of moles of ions for the following aqueous solutions.
(a) 400. mL of 0.10 M NaCl
[tex]NaCl\rightarrow Na^++Cl^-[/tex]
NaCl dissociates to give 2 moles of ions.
[tex]\text{Moles of ion}=\text{Molarity of }NaCl\times \text{Volume of solution (in L)}[/tex]
Volume of solution = 400. mL = 0.400 L
[tex]\text{Moles of ion}=0.10M\times 0.400L=0.04mol[/tex]
Total moles of ion = 0.04 mol × 2 = 0.08 mol
(b) 300. mL of 0.10 M CaCl₂
[tex]CaCl_2\rightarrow Ca^{2+}+2Cl^-[/tex]
CaCl₂ dissociates to give 3 moles of ions.
[tex]\text{Moles of ion}=\text{Molarity of }CaCl_2\times \text{Volume of solution (in L)}[/tex]
Volume of solution = 300. mL = 0.300 L
[tex]\text{Moles of ion}=0.10M\times 0.300L=0.03mol[/tex]
Total moles of ion = 0.03 mol × 3 = 0.09 mol
(c) 200. mL of 0.10 M FeCl₃
[tex]FeCl_3\rightarrow Fe^{3+}+3Cl^-[/tex]
FeCl₃ dissociates to give 4 moles of ions.
[tex]\text{Moles of ion}=\text{Molarity of }FeCl_3\times \text{Volume of solution (in L)}[/tex]
Volume of solution = 200. mL = 0.200 L
[tex]\text{Moles of ion}=0.10M\times 0.200L=0.02mol[/tex]
Total moles of ion = 0.02 mol × 4 = 0.08 mol
From this we conclude that, [tex]CaCl_2[/tex] aqueous solutions contains the greatest number of ions.
Hence, the correct option is, (b) 300. mL of 0.10 M CaCl₂
The aqueous solution that contains the greatest number of ions is b. 300. mL of 0.10 M CaCl₂.
a. The number of moles in 400. mL of 0.10 M NaCl is:
[tex]0.400 L \times \frac{0.10mol}{L} = 0.040mol[/tex]
Each mole of NaCl contains 2 moles of ions (1 Na⁺ and 1 Cl⁻). The moles of ions in 0.040 moles of NaCl are:
[tex]0.040molNaCl \times \frac{2molIons}{1molNaCl} = 0.080 mol Ions[/tex]
b. The number of moles in 300. mL of 0.10 M CaCl₂ is:
[tex]0.300 L \times \frac{0.10mol}{L} = 0.030mol[/tex]
Each mole of CaCl₂ contains 3 moles of ions (1 Ca²⁺ and 2 Cl⁻). The moles of ions in 0.030 moles of CaCl₂ are:
[tex]0.030molNaCl \times \frac{3molIons}{1molNaCl} = 0.090 mol Ions[/tex]
c. The number of moles in 200. mL of 0.10 M FeCl₃ is:
[tex]0.200 L \times \frac{0.10mol}{L} = 0.020mol[/tex]
Each mole of FeCl₃ contains 4 moles of ions (1 Fe³⁺ and 3 Cl⁻). The moles of ions in 0.020 moles of FeCl₃ are:
[tex]0.020molNaCl \times \frac{4molIons}{1molNaCl} = 0.080 mol Ions[/tex]
The aqueous solution that contains the greatest number of ions is b. 300. mL of 0.10 M CaCl₂.
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determine whether each of the following electron configurations is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choices.
This is an incomplete question, here is a complete question.
Determine whether each of the following electron configurations is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choices.
(a) [tex]1s^22s^22p^63s^23p^5[/tex]
(b) [tex]1s^22s^22p^63s^23p^63d^74s^2[/tex]
(c) [tex]1s^22s^22p^63s^23p^63d^{10}4s^24p^6[/tex]
(d) [tex]1s^22s^22p^63s^23p^63d^4s^1[/tex]
Answer :
(a) [tex]1s^22s^22p^63s^23p^5[/tex] → Halogen
(b) [tex]1s^22s^22p^63s^23p^63d^74s^2[/tex] → Transition metal
(c) [tex]1s^22s^22p^63s^23p^63d^{10}4s^24p^6[/tex] → Transition metal
(d) [tex]1s^22s^22p^63s^23p^63d^4s^1[/tex] → Transition metal
Explanation :
Inert gas : These are the gases which lie in group 18.
Their general electronic configuration is: [tex]ns^2np^6[/tex] where n is the outermost shell.
Halogen : These are the elements which lie in group 17.
Their general electronic configuration is: [tex]ns^2np^5[/tex] where n is the outermost shell.
An alkali metal : These are the elements which lie in group 1.
Their general electronic configuration is: [tex]ns^1[/tex] where n is the outermost shell.
An alkaline earth metal : These are the elements which lie in group 2.
Their general electronic configuration is: [tex]ns^2[/tex] where n is the outermost shell.
Transition elements : They are the elements which lie between 's' and 'p' block elements. These are the elements which lie in group 3 to 12. The valence electrons of these elements enter d-orbital.
Their general electronic configuration is: [tex](n-1)d^{1-10}ns^{0-2}[/tex] where n is the outermost shell.
(a) [tex]1s^22s^22p^63s^23p^5[/tex]
The element having this electronic configuration belongs to the halogen family.
(b) [tex]1s^22s^22p^63s^23p^63d^74s^2[/tex]
The element having this electronic configuration belongs to the transition family.
(c) [tex]1s^22s^22p^63s^23p^63d^{10}4s^24p^6[/tex]
The element having this electronic configuration belongs to the transition family.
(d) [tex]1s^22s^22p^63s^23p^63d^4s^1[/tex]
The element having this electronic configuration belongs to the transition family.
1. [tex][Ar]4s^2 3d^10 4p^6[/tex] is an inert gas (krypton, Kr).
2. [tex][Kr]5s^2 4d^10 5p^2[/tex] is a transition metal (zinc, Zn).
3. [tex][He]2s^1[/tex] is an alkali metal (lithium, Li).
4. [tex][Ne]3s^2 3p^5[/tex] is a halogen (chlorine, Cl).
5. [tex][Ar]4s^2[/tex] is an alkaline earth metal (calcium, Ca).
6. [tex][Xe]6s^2 4f^14 5d^10 6p^3[/tex] is not a transition metal but a post-transition metal (bismuth, Bi).
To determine the type of element based on its electron configuration, one must understand the characteristic configurations of the different groups of elements in the periodic table. Here are some general rules:
- Inert gases (also known as noble gases) have completely filled s and p subshells in their valence shell. Their configurations typically end in [tex]ns^2 np^6[/tex], except for helium, which has [tex]1s^2[/tex].
- Halogens have the [tex]ns^2 np^5[/tex] configuration in their valence shell, with the exception of helium, which has [tex]1s^2[/tex].
- Alkali metals have a single electron in their outermost s subshell, denoted as [tex]ns^1[/tex].
- Alkaline earth metals have two electrons in their outermost s subshell, denoted as [tex]ns^2[/tex].
- Transition metals have incompletely filled d subshells in their penultimate energy level. Their configurations typically start with [tex](n-1)d^1 to (n-1)d^10[/tex] in the valence shell.
Let's analyze the given electron configurations:
1. [tex][Ar]4s^2 3d^10 4p^6[/tex]
- This configuration has a filled 4s subshell, a filled 3d subshell (10 electrons), and a filled 4p subshell. It corresponds to the configuration of an inert gas, specifically krypton (Kr), which has the full configuration [tex][Ar]4s^2 3d^10 4p^6[/tex].
2. [tex][Kr]5s^2 4d^10 5p^2[/tex]
- This configuration has a filled 5s subshell and a filled 4d subshell, but the 5p subshell is not filled (only 2 electrons out of a possible 6). This does not correspond to an inert gas, a halogen, an alkali metal, or an alkaline earth metal. It is a configuration of an element in group 12, which is a transition metal. Specifically, this is the configuration for zinc (Zn).
3. [tex][He]2s^1[/tex]
- This configuration has a single electron in the 2s subshell, which is characteristic of an alkali metal. Specifically, this is the configuration for lithium (Li).
4. [tex][Ne]3s^2 3p^5[/tex]
- This configuration has a filled 3s subshell and the 3p subshell is missing one electron to be filled (5 electrons out of a possible 6). This is the configuration of a halogen, specifically chlorine (Cl).
5. [tex][Ar]4s^2[/tex]
- This configuration has a filled 4s subshell, which is characteristic of an alkaline earth metal. Specifically, this is the configuration for calcium (Ca).
6. [tex][Xe]6s^2 4f^14 5d^10 6p^3[/tex]
- This configuration has a filled 6s subshell, a filled 4f subshell (14 electrons), and a filled 5d subshell (10 electrons), but the 6p subshell is not filled (only 3 electrons out of a possible 6). This does not correspond to an inert gas, a halogen, an alkali metal, or an alkaline earth metal. It is the configuration of an element in group 13, which is not a transition metal but a post-transition metal. Specifically, this is the configuration for bismuth (Bi).
In summary:
1. [tex][Ar]4s^2 3d^10 4p^6[/tex] is an inert gas (krypton, Kr).
2. [tex][Kr]5s^2 4d^10 5p^2[/tex] is a transition metal (zinc, Zn).
3. [tex][He]2s^1[/tex] is an alkali metal (lithium, Li).
4. [tex][Ne]3s^2 3p^5[/tex] is a halogen (chlorine, Cl).
5. [tex][Ar]4s^2[/tex] is an alkaline earth metal (calcium, Ca).
6.[tex][Xe]6s^2 4f^14 5d^10 6p^3[/tex] is not a transition metal but a post-transition metal (bismuth, Bi).
A gasoline spill is approximately 4 liters of liquid. What volume of vapor is created at 1 bar and 293 K when the liquid evaporates? The density of regular gasoline can be estimated by treating it as pure isooctane (2,2,4-trimethylpentane rhoL = 0.692 g/cm3) at 298 K and 1 bar.
Answer:
[tex]V=591.748 L[/tex]
Explanation:
Assumption:
Ideal Vapors/Ideal gas
Formula for ideal Gas:
[tex]PV=nR_uT[/tex]
Where:
P is the pressure
V is the Volume
n is the number of moles = m/M
R_u is Universal Gas Constant=0.08314 L*bar/(K*mol)
T is the temperature in Kelvin
Calculating Number of moles n:
n=Mass/Molar Mass
[tex]Mass=\rho_L*Volume\\Mass=0.692*(4000 cm^3)........... (4 liter * 1000cm^3/Liters =4000 cm^3)\\Mass=2768 g[/tex]
Molar Mass of gasoline=114g/mol
[tex]n=\frac{2768}{114} \\n=24.2807 moles[/tex]
Now:
[tex]PV=nR_uT[/tex]
[tex]V=\frac{nR_uT}{P}\\V=\frac{24.2807*0.08314*293}{1 bar}\\V=591.748 L[/tex]
An example of metal-bearing deposit formed when a sulphide liquid separated from an ultramafic magma by becoming supersaturated and immiscible is
Answer: SUDBURY, ONTARIO.
Explanation: SUDBURY,is a place in Ontario, Canada known to have been formed as a result of the separation of Sulphur liquid from ultramafic Magma by becoming supersaturated and immiscible. Over 100millions tons of Sulphur liquid and some quantities of other metals like Nickel,iron have been released into the atmosphere as a result of mining activities of that period.
Sudbury basin is famous for its geological feature that hosts about the largest concentrations of nickel-copper sulphides in the world is believed to have been formed by a meteorite impact 1.8 billion years ago.
Select all that apply:
A)The mass ratio of oxygen to carbon in CO is twice the mass ratio of oxygen to carbon in CO2.
B)The mass ratio of oxygen to carbon in CO is 1.33 for every sample of CO.
C)mass ratio of oxygen to carbon in CO2 is 2.667 for every sample of CO2.
D)For two compounds of C and O, the mass ratio of C to O in one compound is a multiple of the mass ratio of C to O in the other compound.
Option B, C and D are correct.
Explanation:Carbon is a non metallic element with the atomic number 6 and mass number 12. Whereas oxygen is also a non metallic element with the atomic number 8 and mass number of 16.
In carbon monoxide, the mass ratio of oxygen to carbon is 16:12 =1.33. This ratio is same for every sample of carbon monoxide, because carbon monoxide has the universal formula of CO.
Similarly In carbon dioxide , the mass ratio of oxygen to carbon is 32:12 =2.667. This ratio is same for every sample of carbon dioxide, because carbon dioxide has the universal formula of [tex]CO_2[/tex].
Even we can see that the mass ratio of oxygen to carbon in carbon dioxide is just twice the mass ratio of oxygen to carbon in carbon monoxide, because of presence of twice as much as oxygen per molecule of carbon dioxide than carbon monoxide.
Draw the molecular structures of citrate, isocitrate, α-ketoglutarate, and Succinyl-CoA in a pathway sequence. Show which carbons came from acetyl-CoA and which go off as CO2.
Answer: check the picture
Explanation:
Answer:
In the oxidation of Pyruvate to Acetyl CoA one carbon atom is released as CO2, However, the oxidation of the remaining two carbon atoms in acetate to CO2, requires a complex, eight step pathway, the citric-acid cycle.
Explanation:
Overall, one turn of the citric acid cycle releases two carbon dioxide molecules and produces three {NADH} one {FADH2} and one ATP or GTP. The Citric acid cycle goes around twice for each molecule of glucose that enters cellular respiration because there are two pyruvate and thus, two acetyl {CoA}s are made per glucose.
Consider this reaction:
2Cl2O5 (g) → 2Cl2 (g) + 5O2 (g)
At a certain temperature it obeys this rate law.
rate = (6.48 M-1 • s-1)[Cl2O5]2
Suppose a vessel contains Cl2O5 at a concentration of 1.16 M. Calculate the concentration of Cl2O5 in the vessel 0.820 seconds later. You may assume no other reaction is important.
Round your answer to 2 significant digits.
Answer : The concentration of [tex]Cl_2O_5[/tex] in the vessel 0.820 seconds later is, 0.16 M
Explanation :
The given reaction is:
[tex]2Cl_2O_5(g)\rightarrow 2Cl_2(g)+5O_2(g)[/tex]
The rate law expression is:
[tex]rate=(6.48M^{-1}s^{-1})[Cl_2O_5]^2[/tex]
The expression used for second order kinetics is:
[tex]kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}[/tex]
where,
k = rate constant = [tex]6.48M^{-1}s^{-1}[/tex]
t = time = 0.820 s
[tex][A_t][/tex] = final concentration = ?
[tex][A_o][/tex] = initial concentration = 1.16 M
Now put all the given values in the above expression, we get:
[tex]6.48\times 0.820=\frac{1}{[A_t]}-\frac{1}{1.16}[/tex]
[tex][A_t]=0.16M[/tex]
Therefore, the concentration of [tex]Cl_2O_5[/tex] in the vessel 0.820 seconds later is, 0.16 M
Calculate the molality of a solution formed by adding 4.40 g NH4Cl to 11.0 g of water.
To calculate the molality of a solution, divide the moles of solute by the mass of solvent (in kg). In this case, the molality of the NH4Cl solution is 7.45 m.
To calculate the molality of a solution, we need to first calculate the moles of NH4Cl and water.
Calculate the moles of NH4Cl by dividing the given mass by the molar mass of NH4Cl (53.49 g/mol): 4.40 g NH4Cl / 53.49 g/mol = 0.082 mol NH4Cl.
Calculate the moles of water by dividing the given mass by the molar mass of water (18.015 g/mol): 11.0 g H2O / 18.015 g/mol = 0.61 mol H2O.
Now we can calculate the molality using the moles of solute and the mass of the solvent:
Molality = moles of solute / mass of solvent (in kg)
Molality = 0.082 mol NH4Cl / 0.011 kg H2O = 7.45 m NH4Cl.
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Determine if the results of the following word problem adhere to the Law of Conservation of Mass. 1. A chemist combines 4.9 g of hydrogen gas with 9.4 grams of nitrogen gas to form 11.4 g of ammonia. 2.9 g of nitrogen gas is remaining
Answer: The results agree with the law of conservation of mass
Explanation:
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. On the reactant side, the total mass of reactants is 14.3g and the total product masses is also 14.3g. That implies that no mass was !most in the reaction. The sum of masses on the left hand side corresponds with sum of masses on the right hand side of the reaction equation.
26.6 mL of 2.50 M stock solution of sucrose is diluted to 50.0 mL. A 16.0 mL sample of the resulting solution is then diluted to 45.0 mL. A 20.0 mL sample of this solution is then diluted to 75.0 mL. What is the concentration of sucrose in the final solution?
Answer:
In the final solution, the concentration of sucrose is 0.126 M
Explanation:
Hi there!
The number of moles of solute in the volume taken from the more concentrated solution will be equal to the number of moles of solute in the diluted solution. Then, the concentration of the first solution can be calculated using the following equation:
Ci · Vi = Cf · Vf
Where:
Ci = concentration of the original solution
Vi = volume of the solution taken to prepare the more diluted solution.
Cf = concentration of the more diluted solution.
Vf = volume of the more diluted solution.
For the first dillution:
26.6 ml · 2.50 M = 50.0 ml · Cf
Cf = 26.6 ml · 2.50 M / 50.0 ml
Cf = 1.33 M
For the second dilution:
16.0 ml · 1.33 M = 45.0 ml · Cf
Cf = 16.0 ml · 1.33 M / 45.0 ml
Cf = 0.473 M
For the third dilution:
20.0 ml · 0.473 M = 75.0 ml · Cf
Cf = 20.0 ml · 0.473 M / 75.0 ml
Cf = 0.126 M
In the final solution, the concentration of sucrose is 0.126 M