Answer: Polar molecules have an equal number of positive and negative particles.
Explanation: There are two types of molecules:
1) Polar molecules: This molecule is formed when two different atoms having different electronegativities combine together. The more electronegative atom attracts the shared pair of electron towards itself, thus acquiring a partial negative charge and other atom acquiring partial positive charge. This results in the formation of dipole. In this equal number of positive and negative particles.
For example: HCl. As this molecule is covalent in nature and is also a polar molecule.
2) Non-polar molecules: This is formed when two atoms of same electronegativity combine together. For Example: [tex]H_2,O_2[/tex] etc.
Hence, Polar molecules have an equal number of positive and negative particles.
Which hydrocarbon will provide more heat when allowed to react with oxygen? Hint: Use the heat of combustion data in the alkane properties table. C6H14 C6H12 C2H6 C3H8
Answer:
C6H14
Explanation:
Odyssey ware
Which of the following solutions will not neutralize a weak base solution of pyridine (C5H5N)?
vinegar
ammonia
carbonated soda drink
pickle juice
Answer:
The correct answer is option B, ammonia
Explanation:
A weak base solution like pyridine (C5H5N) can be neutralized in the presence of an acid only. A weak base in no case shall be neutralized by another base. Since ammonia is also a base thus it cannot neutralize another base. In a neutralized mixture, slats are produced by equal contribution from both the acid and base. However, when a weak base is placed into another base their will be more OH- ions but very rare H+ ion. Thus mixture with excess of OH- will again be a base only.
A cart is pulled by a force of 250 N at an angle of 35° above the horizontal. The cart accelerates at 1.4 m/s2. The free-body diagram shows the forces acting on the cart.
The mass of the cart, to the nearest whole number, is kg?
Answer : The mass of the cart is, 146 Kg.
Solution : Given,
Force = 250 N
Angle = [tex]35^o[/tex]
Acceleration = [tex]1.4m/s^2[/tex]
Formula used :
[tex]F\times \cos \theta=m\times a[/tex]
where,
F = force
[tex]\theta[/tex] = angle
a = acceleration
m = mass of the cart
Now put all the values in the above formula, we get the mass of the cart.
[tex]250N\times \cos (35^o)=m\times (1.4m/s^2)[/tex]
[tex]m=146Kg[/tex]
Therefore, the mass of the cart is, 146 Kg.
What are the two parts of an atom?
Answer:
The nucleus and the electron cloud.
Explanation:
The protons and neutrons are in the nucleus and the electrons and in the electron cloud. Hope this helps!
What property do all of the group 18 elements have that make them stand out from other elements?
Aspirin is prepared by reacting salicylic acid with excess ethanoic anhydride. in an experiment, 50.05 g of salicylic acid was converted into 55.45 g of aspirin. what was the percentage yield
Final answer:
The percentage yield of aspirin is calculated by comparing the actual yield from the experiment to the theoretical yield determined by stoichiometry. Calculations are based on the molar masses of salicylic acid and aspirin and the stoichiometry of the reaction between them.
Explanation:
To calculate the percentage yield of aspirin from salicylic acid, first determine the theoretical yield and then compare it to the actual yield. The reaction between salicylic acid and ethanoic anhydride is given as:
C7H6O3 + (CH3CO)2O → C9H8O4 + CH3COOH
The molar mass of salicylic acid (C7H6O3) is 138.12 g/mol, and the molar mass of aspirin (C9H8O4) is 180.16 g/mol. If all 50.05 g of salicylic acid reacted, the maximum amount of aspirin that could be formed is calculated using stoichiometry:
Theoretical yield = (50.05 g of salicylic acid * 1 mol salicylic acid / 138.12 g salicylic acid) * (180.16 g aspirin / 1 mol aspirin)
From the actual experiment, 55.45 g of aspirin was obtained. Now, calculate the percentage yield:
Percentage yield = (Actual yield / Theoretical yield) * 100%
By inserting the values into this equation, the percentage yield can be found. Remember that a percentage yield above 100% is not practically possible, indicating that there may have been an error in the experiment or in calculating the yields.
How does the solubility of a gas change with decreasing temperature?
A bug travels at the rate of 3.0 miles per hour. How fast is this in um/nsec? Hint: 2.54cm = 1 inch and 1 mile = 5,280 feet
What does oxidation mean? what does reduction mean? which of them is endergonic and which is exergonic?
Answer:
1. Oxidation is when a molecule, atom or ion losses an Electron. 2. Reduction is when a molecule, atom or ion gains an electron. 3. endergonic means absorbing energy in the form of work whereas Exergonic means releasing energy in the form of work.
Explanation:
What is the overall fusion reaction that converts mass into other forms of energy in the sunâs core? what is the overall fusion reaction that converts mass into other forms of energy in the sunâs core? 3 helium nuclei become 1 carbon nucleus e = mc2 4 hydrogen nuclei become 1 helium nucleus 2 hydrogen nuclei become 1 helium nucleus?
The fusion reaction in the sun's core that converts mass into other forms of energy is known as the proton-proton chain reaction. This process involves the combination of four hydrogen nuclei to form one helium nucleus and the difference in mass is released as energy according to Einstein's equation E=mc^2.
Explanation:The overall fusion reaction that converts mass into energy in the core of the sun is known as nuclear fusion, specifically a process called the proton-proton chain reaction. This is a series of nuclear reactions which results in the combination of four hydrogen nuclei (protons) to form one helium nucleus, with the release of two positrons, two neutrinos (usually called solar neutrinos), and six photons. This is represented by the following reaction:
4H -> He + 2e+ + 2v + 6γ
The mass of the four hydrogen atoms is greater than that of the helium atom produced and, according to Einstein’s equation E=mc^2, the difference in mass is released as energy. The released energy powers the sun and produces the sunlight that we see.
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The sun's energy is generated from a complex process of nuclear fusion, called the proton-proton chain, where four hydrogen nuclei are transformed into a helium nucleus, releasing a significant amount of energy as per Einstein's equation E=mc².
Explanation:The overall nuclear fusion reaction that occurs in the sun involves the conversion of hydrogen nuclei (protons) into helium. This begins when high temperatures within the sun's core cause two protons to combine, forming a deuterium nucleus, an isotope of hydrogen with one proton and one neutron. Further, through a process called the proton-proton chain, more reactions occur which lead to the transformation of four hydrogen nuclei into one helium nucleus, releasing significant energy in the process.
Throughout this process, due to the conversion of mass into energy as postulated by Einstein's equation, E=mc², a tremendous amount of energy is released. Energy in fusion reactions is released in forms such as light (photons), neutrinos, and other particles. This overall process of fusion is the principal source of energy in the sun.
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A normal concentration of glucose, or sugar, in the blood is 95 mg/dl. how many grams of sugar would be present per liter of blood? show the conversion factors you use.
You are a stem cell therapist who is researching a stem cell therapy to help broken bones heal faster. This therapy involves injecting stem cells into broken bones. Which type of cells would you likely be injecting?
Answer: Osteoblasts!
Explanation:
They form bone.
Calculate the dipole moment for hf (bond length 0.917 å), assuming that the bond is completely ionic.
The dipole moment of HF can be calculated through the charge of an electron and bond length. Upon conversion into Debye, it's found to be approximately 4.4 D assuming the HF bond to be completely ionic.
Explanation:The dipole moment of a molecule depends on the difference in electronegativity between the atoms and the distance between the atoms' nuclei. In the case of HF (Hydrogen Fluoride), assuming the bond is completely ionic, we can calculate the dipole moment using the charge of an electron (1.60218 × 10-¹⁹ C) and the bond length (converted to meters).
The bond length of HF given is 0.917 angstroms, which is equivalent to 0.917 x 10-10m or 9.17 x 10-11m. This allows us to calculate the dipole moment in coulomb-meters (C.m) as (1.60218 × 10-¹⁹ C) * (9.17 x 10⁻¹¹m) = 14.69 x 10⁻³⁰ Cm.
We usually express dipole moments in Debyes. To convert C.m to Debye, we use the conversion factor where 1 Debye (D) = 3.336 x 10⁻³⁰ C.m, which gives us a dipole moment of approximately 4.4 D for HF.
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Which orbital would the electron of a ground state hydrogen atom occupy? 1s 1p 2p none of the above 0s?
In the ground state, a hydrogen atom's electron occupies the 1s orbital, which is the lowest energy state and has a spherically symmetrical probability distribution.
The electron of a ground state hydrogen atom would occupy the 1s orbital. The ground state refers to the lowest energy state available to an electron in an atom.
In hydrogen's case, this is the 1s state, which has n = 1 (the principal quantum number indicating the energy level) and l= 0 (the orbital angular momentum quantum number, which for s orbitals is always zero).
This state is also spherically symmetrical, meaning the electron probability distribution around the nucleus is even in all directions.
Furthermore, the energy order of orbitals shows that 1s is lower than 2s, 2p, 3s, etc., indicating that electrons fill the 1s orbital before any others when in the ground state.
The number of protons in the nucleus of an atom determines the species of the atom, i.e., the element to which the atom belongs. an atom has the same number of protons and neutrons. but the electron number cannot be used instead because
Answer:
its not electrons are negatively charged
Explanation:
When converting from kilometers to meters, the decimal is moved _______. a. three places to the left b. two places to the left c. three places to the right d. two places to the right.
Answer : The correct option is, (c) three places to the right
Explanation :
The conversion used is:
[tex]1km=1000m[/tex]
For example :
The conversion of 3.1 km into m.
As, [tex]1km=1000m[/tex]
So, [tex]3.1km=\frac{3.1km}{1km}\times 1000m=3100m[/tex]
From this we conclude that, when we are converting from kilometers to meters then decimal is moved three places to the right.
Hence, the correct option is, (c) three places to the right
Which element has the lowest mass per nuclear particle and therefore cannot release energy by either fusion or fission?
Final answer:
Iron (Fe) has the highest binding energy per nucleon, making it the most stable element and unable to release energy by fusion or fission.
Explanation:
The element that has the lowest mass per nuclear particle and cannot release energy by either fusion or fission is iron (Fe). Iron is the most stable element due to its highest binding energy per nucleon. Energy can be extracted by fusing elements lighter than iron, but once iron is formed, fusing heavier elements requires the addition of energy instead of releasing it. Similarly, fission reactions release energy with heavy, unstable nuclei that have low binding energies, such as uranium-235 or uranium-238. Since iron has a high binding energy and lies at the peak of the binding energy curve, it neither releases energy via fusion past this point, nor can it effectively release energy through fission.
The pharmacy stocks a 90% w/v solution of drug 'w'. you need to prepare 200ml of a 5mg/ml solution for a patient. what volume of the stock solution will you need?
The ph of a 0.55 m aqueous solution of hypobromous acid, hbro, at 25.0°c is 4.48. what is the value of ka for hbro?
Answer:
The value of dissociation constant for the hypobromous acid is [tex]1.993\times 10^{-9}[/tex].
Explanation:
The pH of the solution = 4.48
Concentration of hypobromous acid,[tex][HBrO]=c=0.55 M[/tex]
The equilibrium reaction for dissociation of HBrO (weak acid) is,
[tex]HBrO\rightleftharpoons OBr^-+H^+[/tex]
initially conc. c 0 0
At eqm. [tex]c(1-\alpha )[/tex] [tex]c\alpha [/tex] [tex]c\alpha [/tex]
First we have to calculate the concentration of value of degree of dissociation [tex]\alpha [/tex].
Expression for dissociation constant is given as:
[tex]k_a=\frac{(c\alpha )(c\alpha )}{c(1-\alpha )}=\frac{c(\alpha )^2}{(1-\alpha )}[/tex]..(1)
[tex][H^+]=c\alpha [/tex]
[tex]pH=4.48=-\log[H^+]=-\log[c\alpha ]=-\log[0.55 M\times \alpha ][/tex]
[tex]\alpha =6.0205\times 10^{-5}[/tex]
Substituting all the values in (1), we get the value of dissociation constant:
[tex]K_a=\frac{0.55 M(6.0205\times 10^{-5})^2}{(1-(6.0205\times 10^{-5}))}[/tex]
[tex]K_a=1.993\times 10^{-9}[/tex]
The value of dissociation constant for the hypobromous acid is [tex]1.993\times 10^{-9}[/tex].
A 0.55 M aqueous solution of HBrO has a pH of 4.48. The value of Ka for HBrO is 1.99 × 10⁻⁹.
HBrO is a weak acid according to the following equation.
HBrO ⇄ H⁺ + BrO⁻
Given the pH is 4.48, the concentration of H⁺ is:
[tex]pH = -log [H^{+} ]\\[H^{+} ] = antilog-pH = antilog-4.48 = 3.31 \times 10^{-5} M[/tex]
Given the initial concentration of the acid (Ca) is 0.55 M, we can calculate the acid dissociation constant (Ka) using the following expression.
[tex]Ka = \frac{[H^{+}]^{2} }{Ca} = \frac{(3.31 \times 10^{-5} )^{2} }{0.55} = 1.99 \times 10^{-9}[/tex]
A 0.55 M aqueous solution of HBrO has a pH of 4.48. The value of Ka for HBrO is 1.99 × 10⁻⁹.
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Write the net chemical equation for the production of aluminum from aluminum hydroxide and carbon. be sure your equation is balanced.
To produce aluminum from aluminum hydroxide and carbon, the balanced chemical equation is: 2 Al(OH)₃(s) + 3 C(s) → 2 Al(s) + 3 CO(g) + 3 H₂O(g). This ensures all elements are balanced.
To write the net chemical equation for the production of aluminum from aluminum hydroxide and carbon, we must consider the typical reaction: Al(OH)₃(s) + C(s) → Al(s) + CO(g) + H₂O(g)
First, note the elements involved: Aluminum (Al), Carbon (C), Oxygen (O), and Hydrogen (H). We start with the unbalanced equation: 2 Al(OH)₃(s) + 3 C(s) → 2 Al(s) + 3 CO(g) + 3 H₂O(g)Now let’s balance it:
There are 2 Al atoms on both sides.There are 6 O atoms on the left (from 2 Al(OH)₃) and 6 on the right (3 CO and 3 H₂O).There are 6 H atoms on the left (in 2 Al(OH)₃) and 6 H atoms on the right (in 3 H₂O).There are 3 C atoms on both sides.Therefore, the balanced equation is: 2 Al(OH)₃(s) + 3 C(s) → 2 Al(s) + 3 CO(g) + 3 H₂O(g)
How many liters of hydrogen gas are needed to react with CS2 to produce 6.5 L of CH4 at STP
Use complete sentences to explain how you determined the mass of oxygen in the compound produced in the virtual lab, and how the mass of each element can be used to determine the empirical formula of the compound.
Answer : To determine the mass of oxygen in the compound produced in the virtual lab, it should be weighed and subtracted from the total weight of the compound. The mass pf each element can be used to determine the empirical formula of the compound by finding out the molar ratios of the individual elements present in the compound. Molar ratios can be obtained by dividing elements by atomic masses of individual elements.
One has to spot the smallest moles of the elements present in the compound and then it has to be divided by rest of the elements in the compound to find the empirical formula of that compound.
Where are electrons in an atom located? moving outside the nucleus inside the nucleus attached to neutrons
The number of particles in 1 mole of hydrogen gas is ________.
Which of the following conditions increases the frequency of collisions without changing the energy or concentration of reactants?
A: increasing the surface area of the substance
B: adding more reactant molecules
C: increasing the temperature
D: increasing the pressure
Answer:
A: increasing the surface area of the substance
Explanation:
Joey was taking a chemistry test. one question asked him to write the electron configuration for polonium (po). he wrote it out like this: 1s22s22p63s23p64s23d104p65s24d105p66s25d106p4. joey’s teacher marked it wrong. why?
Polonium has an atomic number of 84 in the periodic table and is solid at 20 degrees Celsius. It is an alpha emitter which is used to extract a thin film for stainless steel. They are used for antistatic devices and a good source of heat for space machines. The correct electron configuration of a polonium atom is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p4. What is lacking in his configuration is the presence of the f sub shell. He should have added 4f14 before 5d10 because if he did not add it, it would give another element.
the graph below shows how solubility changes with temperature
Answer:
Option C) Na2SO4 and Na2HAsO4
Explanation:
The solubility of salts can be affected by many things (pH, temperature, etc), this is why when comparing the solubility of two or more salts it's important to establish the conditions.
In this case the graph was made for changes in Temperature, so the first thing is to identify the T=40°C and then, which curves cross at that point.
As can be seen, the red curve (Na2HAsO4) and the blue curve (Na2SO4 ) cross at 40°C indicating that those compounds have similar solubilities at that temperature.
If you are given an unknown liquid that is 1.0 L and has the mass of 500 grams which of the substance would it be. Distilled Water Density= 1.0g/cm^3, Propane density 0.494 g/cm^3, Salt Water density 1.025 g/cm^3 or Liquid Gold 17.31 g/cm^3?
The unknown liquid is most likely Propane.
To determine the identity of the unknown liquid, we calculate its density and compare it to the densities of known substances. Density is defined as mass divided by volume. Given that the mass of the unknown liquid is 500 grams and the volume is 1.0 L (which is equivalent to 1000 cm3), we use the formula:
Density = Mass / Volume
This gives us:
Density = 500 g / 1000 cm3 = 0.5 g/cm3
Comparing this value to the given options:
Distilled Water Density = 1.0 g/cm3
Propane Density = 0.494 g/cm3
Salt Water Density = 1.025 g/cm3
Liquid Gold Density = 17.31 g/cm3
The density of the unknown liquid (0.5 g/cm3) is closest to that of Propane (0.494 g/cm3), so the unknown liquid is most likely Propane.
Which of these solutions has the lowest freezing point?
0.25 M NaCl
0.5 M NaCl
1.0 M NaCl
1.5 M NaCl
2.0 M NaCl
Answer is: 2.0 M NaCl.
Change in freezing point from pure solvent (water) to solution (sodium chloride solution): ΔT = i · Kf · c.
Kf - molal freezing-point depression constant for water is 1.86°C/m.
c- molarity of the solution.
i - Van't Hoff factor.
Because molal freezing-point depression constant and Van't Hoff factor are the same for all five solutions, freezing point depends on molarity of the solution.
The higher is the molarity, the lower is freezing point.
The temperature at which the phase transition solid-liquid occurs is the melting point or the freezing point.
Answer : The correct option is, 2.0 M NaCl
Explanation :
Formula used for lowering in freezing point :
[tex]\Delta T_f=i\times k_f\times m[/tex]
where,
[tex]\DeltaT_f[/tex] = change in freezing point or freezing point depression
[tex]k_f[/tex] = freezing point constant
m = molality
i = Van't Hoff factor
As we know that the Van't Hoff factor for NaCl will be same for all given concentrations of NaCl and [tex]k_f[/tex] is the constant term. So, freezing point depression directly depends only on the molality of the solution.
That means the more the value of molality, the lower will be the freezing point and vice-versa.
From the given options, 2.0 M NaCl has the lowest freezing point.
Hence, the correct option is, 2.0 M NaCl
How many milliliters of sodium metal, with a density of 0.97 g/mL, would be needed to produce 34.5 grams of sodium hydroxide in the single replacement reaction below?
Unbalanced equation: Na + H2O ---> NaOH + H2
Answer:
35.567mL
Explanation:
Simple, density = mass/volume
Volume = mass/density
Which yields
34.5/0.97 = 35.567milliliters