a 0.175 m weak acid acid solution has ph of 3.25 find ka for the acid

Answers

Answer 1
The acid dissociation constant or Ka is a value used to measure the strength of a specific acid in solution. For a general dissociation of an acid solution,

HA = H+ + A-

we express Ka as follows:

Ka = [H+] [A-] / [HA]

Where the terms represents the concentrations of the acid and the ions. Assuming that the weak acid in the problem is HA, we first calculate for the concentration of H+ from the pH.

pH = - log [H+]
3.25 = - log [H+]
[H+] = 0.0005623 M

By the ICE table, we can calculate the equilibrium concentrations,
        HA      =      H+            +        A-
I      0.175           0                         0
C      -x               +x                      +x
 --------------------------------------------------
E  .174438    0.0005623       0.0005623

Ka = (0.0005623) (0.0005623) / .174438
Ka = 1.81x10^-6
Answer 2
Final answer:

To find the Ka value for the weak acid, we can use the given pH and concentration of the acid solution. The Ka value is calculated using the equation Ka = ([H3O+][A-])/[HA].

Explanation:

To find the value of Ka for the weak acid, we can use the given pH and concentration of the acid solution. We know that the pH is a measure of the concentration of H3O+ ions in a solution, so we can use the pH to calculate the [H3O+] concentration. From the given pH of 3.25, we can determine that the [H3O+] concentration is 10^(-pH). So, [H3O+] = 10^(-3.25) M.

Now, the equilibrium equation for the dissociation of the weak acid is HA(aq) + H2O(l) -> H3O+(aq) + A-(aq). Since we know the [H3O+] concentration, we can assume that the [HA] concentration is equal to the [H3O+] concentration. So, [HA] = [H3O+] = 10^(-3.25) M.

The Ka value is calculated using the equation Ka = ([H3O+][A-])/[HA]. Substituting the given values, Ka = (10^(-3.25)^2)/10^(-3.25). Simplifying this expression gives us the value of Ka for the acid.


Related Questions

Which process does not involve a chemical change? 1. cleaning the shower with lime away 2. burning charcoal on the grill 3. boiling water 4. digesting food?

Answers

3. Boiling water is just a physical change because the only change is in the state of matter and not in the chemical structure of the water.

H2O(l)-->H2O(g)

Final answer:

Boiling water does not involve a chemical change, unlike cleaning the shower with lime away, burning charcoal on the grill, and digesting food.

Explanation:

The process that does not involve a chemical change is boiling water.

Boiling water is a physical change because it does not result in the formation of new substances. When water is boiled, it changes from a liquid to a gas, but the chemical composition of water remains the same.

On the other hand, cleaning the shower with lime away, burning charcoal on the grill, and digesting food all involve chemical changes. Cleaning the shower with lime away involves a chemical reaction to remove lime deposits. Burning charcoal on the grill involves the combustion of carbon compounds. Digesting food involves the breakdown of complex molecules into simpler ones by enzymes in the digestive system.

4). How does the Stoichiometry of a reaction (balanced equation) affect reaction Rate?


Answers

The stoichemistry is to do with the conservation of mass in a chemical reaction so that the mass of the reactants equals the mass of the products. The reaction rate will be affected in such a way that the reaction will proceed at such a rate as required to produce an equal  amount of product so that as the product amount approaches the reactant amount then the rate of the reaction should slow down.

The sugar substitute aspartame is composed of two ________ acids. question 1 options:

Answers

Aspartame is an artificial sweetener that is added to food and beverages as a substitute to table sugar or sucrose. It is apparently 200 times sweet than sucrose. It is also more preferable especially in the food industry because its sweetness lasts longer than sucrose does. Aspartame is a methyl ester from two acidic amino acids, aspartic acid and phenylalanine. It also constitute a small portion of methanol. The composition is 40% aspartic acid, 50% phenylalanine and 10% methanol. This compound was accidentally discovered by James Schlatter when he was trying to test an anti-ulcer drug.

The sugar substitute aspartame is composed of two amino acids.

Aspartame is made from the amino acids aspartic acid and phenylalanine. It is a methyl ester of a dipeptide. Aspartame is 180 times sweeter than sugar and is used as a sugar substitute.

Specifically, aspartame is a methyl ester of a dipeptide made from the amino acids aspartic acid and phenylalanine. These amino acids naturally occur in proteins and contribute to the sweetening properties of aspartame, which is approximately 180 times sweeter than table sugar. Aspartame is widely used in foods and beverages as a non-toxic sugar substitute.

What mass of zinc oxide would be produced by the thermal decomposition of 375 grams of zinc carbonate?
162 grams
44 grams
243 grams
250 grams

Answers

Zinc carbonate has the chemical formula : ZnCO3 and the equation for thermal decomposition is:
ZnCO3 .................> ZnO + CO2
1 mole of ZnCO3 produces one mole of ZnO

From the periodic table:
molar mass of zinc = 65.38 gm
molar mass of carbon = 12 gm
molar mass of oxygen = 16 gm

molar mass of ZnCO3 = 65.38 + 12 + 3(16) = 125.38 gm
molar mass of ZnO = 65.38 + 16 = 81.38 gm

125.38 gm of ZnCO3 produces 81.38 gm of ZnO, therefore:
mass of ZnO in 375 gm = (375 x 81.38) / 125.38 = 243.4 gm

Based on the above calculations, the correct answer is 243 grams


Answer:

C.) 243 grams

Explanation:

I got it right on founders edtell

What is the effect of an insoluble impurity, such as sand, on the observed melting point of a compound?]?

Answers

The effect of an insoluble impurity, such as sand, on the observed melting point of a compound would be none. It will not depress or elevate the melting point of the compound. Instead, it would affect the reading if you are trying to determine the melting point of the compound. This is because you might be missing  the actual melting point of the compound since you will be waiting for the whole sample to liquify. You would not be able to determine exactly that temperature because of the insoluble impurity would have a different melting point than that of the compound.

Final answer:

The presence of an insoluble impurity such as sand in a compound causes a lower observed melting point and a broader melting range, known as melting point depression. The impurity disrupts the crystal lattice, lowering the energy required for the substance to melt, and physically hinders a uniform melting process.

Explanation:

Effect of Insoluble Impurities on Melting Point

The presence of an insoluble impurity, such as sand, in a compound can alter its melting point. Typically, the observed melting point of a compound with impurities is lowered and the range over which melting occurs is broadened. This phenomenon is known as melting point depression, which is akin to freezing point depression. The introduction of an insoluble impurity disrupts the orderly crystal lattice of a pure substance, thereby requiring less energy to break the intermolecular forces among the molecules when heat is applied. Consequently, the substance starts to melt at a lower temperature.

When a compound undergoes melting, impurities like sand do not integrate into the crystal lattice. Instead, they remain as separate entities. As the majority component (for instance, a pure chemical) begins to melt, it may form small pools of liquid, which do not contain the impurity. Since the sand is insoluble, it doesn't contribute to the solution phase and hence doesn't affect the liquid's composition or properties directly. However, the presence of the sand broadens the range over which the compound melts because it can physically hinder the melting process. This leads to a melting range rather than a sharp melting point.

In practice, the presence of impurities can be identified by a melting point that is lower than expected for the pure compound and by a broader range of temperatures over which melting occurs, which is indicative of a less pure substance. Such a broad range is due to the impure solid melting at various temperatures, influenced by the amount and distribution of the impurity.

Give the common name for the structure. ethyl isopropyl ketone tert-butyl ethyl ketone sec-butyl ethyl ketone ethyl isobutyl ketone isobutyl methyl ketone

Answers

The structure for this question is attached. I think the correct answer would be the fourth option. The common name of the structure would be ethyl isobutyl ketone. Other name would be 2-methyl-3-pentanone. It has a chemical formula of C7H14O or (CH3)2CHCH2C(O)CH2CH3. It is classified as an aliphatic ketone and is used as a solvent and a reagent in laboratory experiments. It is a VOC or volatile organic compound. This compound can also be found at times in normal human biofluids and in feces for about 25% of the population. At normal conditions, it exists as a solid compound. 
Final answer:

Common names for ketones include the names of the alkyl groups attached to the carbonyl group followed by 'ketone'. Ethyl methyl ketone is an example with an ethyl group and a methyl group.

Explanation:

The common names for ketones are typically derived by naming the alkyl groups attached to the carbonyl group, followed by the word ketone. For the ketones listed:

Ethyl isopropyl ketone refers to a ketone with an ethyl group and an isopropyl group attached to the carbonyl.Tert-butyl ethyl ketone has a tertiary butyl group and an ethyl group attached.Sec-butyl ethyl ketone consists of a secondary butyl group and an ethyl group attached.Ethyl isobutyl ketone has an ethyl group and an isobutyl group attached.Isobutyl methyl ketone, also known as 3-methyl-2-butanone, has an isobutyl group and a methyl group attached.

For example, the ketone with four carbon atoms, with an ethyl group and a methyl group on either side of the carbonyl, is commonly known as ethyl methyl ketone.

A can of hairspray has a volume of 684 mL and contains 6.43 g of carbon dioxide as the propellant what is the pressure inside the can at 25°C

Answers

Use ideal gas equation

pV = n RT => p = nRT / V

T = 25 + 273.15 K = 298.15 K

V = 684 ml = 0.684 l

R = 0.0821 atm * l / (K*mol)

n = mass / molar mass =

molar mass of CO2 = 12 g/mol + 2*16 g/mol = 44 g/mol

n = 6.43 g / 44 g/mol = 0.14614 mol

=> p = 0.14614 mol * 0.0821 atm*l /(K*mol) * 298.15K / 0.684 l = 5.23 atm

Answer: p = 5.23 atm

A compound is found to be 30.45% n and 69.55 % o by mass. if 1.63 g of this compound occupy 389 ml at 0.00°c and 775 mm hg, what is the molecular formula of the compound?

Answers

1) mass composition

N: 30.45%
O: 69.55%
   -----------
   100.00%

2) molar composition

Divide each element by its atomic mass

N: 30.45 / 14.00 = 2.175 mol

O: 69.55 / 16.00 = 4.346875

4) Find the smallest molar proportion

Divide both by the smaller number

N: 2.175 / 2.175 = 1

O: 4.346875 / 2.175 = 1.999 = 2

5) Empirical formula: NO2

6) mass of the empirical formula

14.00 + 2 * 16.00 = 46.00 g

7) Find the number of moles of the gas using the equation pV = nRT

=> n = pV / RT = (775/760) atm * 0.389 l / (0.0821 atm*l /K*mol * 273.15K)

=> n = 0.01769 moles

8) Find molar mass

molar mass = mass in grams / number of moles = 1.63 g / 0.01769 mol = 92.14 g / mol

9) Find how many times the mass of the empirical formula is contained in the molar mass

92.14 / 46.00 = 2.00

10) Multiply the subscripts of the empirical formula by the number found in the previous step

=> N2O4

Answer: N2O4

The molecular formula of the compound given the percentages and conditions is determined to be N₂O₄ by converting mass percentages to moles, using the ideal gas law to find molar mass, and then refining the empirical formula.


Finding the Molecular Formula:

To determine the molecular formula of the compound with 30.45% nitrogen (N) and 69.55% oxygen (O) by mass, we will follow several steps:

Determine the empirical formula:
Molar masses: N = 14.01 g/mol, O = 16.00 g/mol
Convert mass percentages to moles:
N: 30.45 g / 14.01 g/mol = 2.174 mol
O: 69.55 g / 16.00 g/mol = 4.347 mol
Find the simplest ratio:
N: 2.174 / 2.174 = 1
O: 4.347 / 2.174 = 2

Empirical formula: NO₂Find the molecular weight using the ideal gas law:
P = 775 mm Hg = 1.019 atm, V = 389 mL = 0.389 L, T = 0.00°C = 273.15 K
Use PV = nRT: n = PV/RT = (1.019 atm * 0.389 L) / (0.0821 atm·L/mol·K * 273.15 K) = 0.0174 mol
Molar mass: 1.63 g / 0.0174 mol = 93.68 g/molDetermine the molecular formula:
Empirical formula mass: 14.01 g/mol (N) + 2 * 16.00 g/mol (O) = 46.01 g/mol
Molecular formula mass / Empirical formula mass: 93.68 g/mol / 46.01 g/mol ≈ 2
Molecular formula: (NO₂)₂ = N₂O₄

The molecular formula of the compound is N₂O₄.

Compute the mass percent of carbon, hydrogen, nitrogen, and oxygen in caffeine, C8H10N4O2

Answers

Molar mass of caffeine: 194

Carbon percentage: 12*8 / 194 = 49%

Hydrogen: 10 / 194 = 5%

Nitrogen: 14*4 / 194 = 29%

Oxygen: 16*2 / 194 = 16%
mass percentage of C = 49.48%
mass percentage of H =5.19%
mass percentage of N =28.86
mass percentage of O = 16.48

What is the ph of a solution of 0.50 m acetic acid?

Answers

You need to use the Ka for the acetic acid and the equilibrium equation.

Ka = 1.85 * 10^ -5

Equilibrium reaction: CH3COOH (aq) ---> CH3COO(-) + H(+)

Ka = [CH3COO-][H+] / [CH3COOH]

Molar concentrations at equilibrium

CH3COOH         CH3COO-     H+

 0.50  - x                  x                 x

Ka = x*x / (0.50 - x) = x^2 / (0.50 - x)

Given that Ka is << 1 => 0.50 >> x and 0.50 - x ≈ 0.50

=> Ka ≈ x^2 / 0.50

=> x^2 ≈ 0.50 * Ka = 0.50 * 1.85 * 10^ -5 = 0.925 * 10^ - 5 = 9.25 * 10 ^ - 6

=> x = √ [9.25 * 10^ -6] = 3.04 * 10^ -3 ≈ 0.0030

pH = - log [H+] = - log (x) = - log (0.0030) = 2.5

Answer: 2.5

Which of these are equal to 6.02 x 1023 particles?

12.01 g carbon (C)

44.08 g of silicon dioxide (SiO2)

16 g of ozone (O3)

16.04 g of carbon tetrahydride (CH4)

Answers

16.04 g of carbon tetrahydride (CH4) and 12.01 g carbon (C)

Answer:

Carbon and carbon tetrahydride (methane).

Explanation:

Hello,

In this case, it is not necessary to compute the particles for all the given masses, it is enough by knowing each substance's moles by knowing their molar mass and subsequently proof they equals 1 mole as long as 1 mole equals 6.022x10²³ which is the Avogadro's number; in such a way, the molar masses are:

[tex]M_C=12.01g/mol\\M_{SiO_2}=60.08g/mol\\M_{O_3}=48g/mol\\M_{CH_4}=16.04g/mol[/tex]

Therefore, the two cases are carbon and carbon tetrahydride or methane as shown below:

[tex]ParticlesC=12.01gC*\frac{1molC}{12.01gC}*\frac{6.022x10^{23}particlesC}{1molC} =6.022x10^{23}particlesC\\ParticlesCH_4=12.01gCH_4*\frac{1molCH_4}{12.01gCH_4}*\frac{6.022x10^{23}particlesCH_4}{1molCH_4}=6.022x10^{23}particlesCH_4[/tex]

Best regards.

Consider the total ionic equation below.

Ba2++2NO3-+2Na++CO2/3- >>>>>> BaCO3 +2Na++2NO3-

Which is the net ionic equation for the reaction?

Answers

Ba²⁺(aq) + CO₃²⁻(aq) → BaCO₃(s)

Answer;

Ba²⁺(aq) + CO₃²⁻(aq) → BaCO₃(s)

Explanation;

Ionic equation is a chemical equation that is written only showing the ions that have changed state in the course of a reaction. The rest ions called spectator ions are not involved in the reaction and do not change state thus they are not included when writing ionic equations.

-Aqueous compounds ionize in water to form corresponding ions, while precipitates, gases and pure liquids do not.

In our case; The only ions involved are Ba²⁺ and Co3²⁻, the rest are spectator ions, that is, NO3⁻ and Na⁺.

Thus the ionic equation will be;

Ba²⁺(aq) + CO₃²⁻(aq) → BaCO₃(s)

How many molecules are there in a 1.27kg sample of lithium carbonate

Answers

[tex] 1.04 \times 10^{25} [/tex]

To calculate the number of molecules in a 1.27kg sample of lithium carbonate, convert the mass to grams, calculate the molar mass, convert the mass to moles, and then multiply by Avogadro's number to find the number of molecules. The calculation results in approximately 1.035 x 10²⁵ molecules. We use three significant figures for the final answer.

The question asks how many molecules are there in a 1.27kg sample of lithium carbonate. To find the number of molecules, we first need to calculate the number of moles in 1.27 kg of lithium carbonate and then use Avogadro's number to find the number of molecules.

Convert the mass of the sample from kilograms to grams.

Calculate the molar mass of lithium carbonate (Li₂CO₃).

Use the molar mass to convert the mass of lithium carbonate to moles.

Multiply the number of moles by Avogadro's number (6.02 x 1023 molecules/mol) to find the number of molecules.

Let's perform the calculations:

1.27 kg = 1270 g.

The molar mass of Li₂CO₃ is approximately 73.89 g/mol (Li: ~6.94 g/mol, C: ~12.01 g/mol, O: ~16.00 g/mol x 3).

The number of moles of Li2CO3 in 1270 g is 1270 g
divided by 73.89 g/mol = approximately 17.19 mol.

The number of molecules in 17.19 mol is 17.19 mol x 6.02 x 10²³ = 1.035 x 10²⁵ molecules.

Note that we have limited our final answer to three significant figures based on the precision of the given mass.

Is distilled water homogeneous or heterogeneous?

Answers

it is neither, it is a pure substance.

Final answer:

Distilled water is a homogeneous mixture, as it is a pure substance with a uniform composition throughout. It is produced by distillation, a process that removes impurities and results in water with consistent properties.

Explanation:

Distilled water is an example of a homogeneous mixture, or more precisely, a pure substance. In the distillation process, water is boiled to produce vapor, which is then condensed back to a liquid form. This process removes impurities and dissolved minerals, resulting in water that is uniform in composition throughout. Distilled water has the same properties and composition in every part of the sample, indicating that it is indeed homogeneous. Unlike heterogeneous mixtures, where components can be physically separated and are not evenly distributed, distilled water's uniformity does not allow for such separation as it is a single compound, H2O, throughout its entirety.

What pressure (in atm) will a sample of o2 gas occupy at 100.0 ml, if o2 has a volume of 25.00 ml at 2.0 atm?

Answers

Assuming that the O2 gas acts like an ideal gas, we find the following expression to be approximates of the behaviour of this gas:

P V = n R T                   ---> 1

where,

P = pressure exerted by the gas

V = volume occupied

n = number of moles

R = universal gas constant

T = absolute temperature

Further, we assume that the number of moles and the temperature are constant, hence reducing equation 1 into the form:

P V = k                         ---> 2

where k is a constant. Therefore we can equate two states:

P1 V1 = P2 V2

Since P1, V1 and V2 are given and we are to look for P2:

25 mL * 2 atm = 100 mL * P2

P2 = 0.5 atm

The sample of [tex]{{\text{O}}_2}[/tex] gas at volume 100 mL will occupy a pressure of  

[tex]\boxed{{\text{0}}{\text{.5 atm}}}[/tex]

Further explanation:

Ideal gas:

An ideal gas contains a large number of randomly moving particles that are supposed to have perfectly elastic collisions among themselves. It is just a theoretical concept, and practically no such gas exists. But gases tend to behave almost ideally at a higher temperature and lower pressure.

Ideal gas law is considered as the equation of state for any hypothetical gas. The expression for the ideal gas equation of gas is as follows:

[tex]{\text{PV}}={\text{nRT}}[/tex]                …… (1)                                                                         

Here,

P is the pressure of the gas.

V is the volume of gas.

n denotes the number of moles of gas.

R is the gas constant.

T is the temperature of gas.

Boyle’s law:

It is an experimental gas law that describes the relationship between pressure and volume of the gas. According to Boyle's law, the volume of the gas is inversely proportional to the pressure of the system, provided that the temperature and the number of moles of gas remain constant.

If the temperature and number of moles of gas are constant then the equation (1) will become as follows:

[tex]{\text{PV}}={\text{constant}}[/tex]                  …… (2)                                                                                                        

Or it can also be expressed as follows:

[tex]{{\text{P}}_1}{{\text{V}}_1}={{\text{P}}_2}{{\text{V}}_2}[/tex]                        …… (3)                                                                                        

Here,

[tex]{{\text{P}}_1}[/tex] is the initial pressure.

[tex]{{\text{P}}_2}[/tex] is the final pressure.

[tex]{{\text{V}}_1}[/tex] is the initial volume.

[tex]{{\text{V}}_2}[/tex] is the final volume.

Rearrange the equation (3) for [tex]{{\text{P}}_2}[/tex]  , and we get,

[tex]{{\text{P}}_2}=\frac{{{{\text{P}}_1}{{\text{V}}_1}}}{{{{\text{V}}_2}}}[/tex]                      …… (4)                                                                                 

[tex]{{\text{P}}_1}[/tex] is 2.0 atm.

[tex]{{\text{V}}_1}[/tex] is 25 mL.

[tex]{{\text{V}}_2}[/tex] is 100 mL.

Substitute the values of [tex]{{\text{P}}_1}[/tex] , [tex]{{\text{V}}_1}[/tex] and [tex]{{\text{V}}_2}[/tex]  in equation(4).

[tex]\begin{aligned}{{\text{P}}_2}&=\frac{{\left( {{\text{25 atm}}}\right)\times\left({{\text{2 mL}}}\right)}}{{\left({{\text{100 mL}}}\right)}}\\&={\text{0}}{\text{.5 atm}}\\\end{aligned}[/tex]

Learn more:

1. How many atoms of hydrogen are present in 2.92g of a water molecule: https://brainly.com/question/899408

2. Identify the intermolecular forces present between given molecules: https://brainly.com/question/10107765

Answer details:

Grade: Senior school

Subject: Chemistry

Chapter: Ideal gas equation.

Keywords: ideal gas, pressure, volume, temperature, number of moles, initial, final, equation, 25 atm, 2 mL, 100 mL, and 0.5 atm.

What is the volume of 55 L of gas initially at 500 K and 4.25 atm when conditions change to STP?

Answers

The general gas law equation that is formed by combining the three laws of Boyle, Charle and Guy Lussac is written as:
(PV/T)1 = (PV/T)2
STP conditions means that T= 273 kelvin and P = 1 atmospheric pressure
Based on the above rule, we calculate V2 as follows:
(4.25*55)/500 = (1*V)/273
V2 = 127.599 liters

Extra notes:
Boyles law: volume and pressure of a certain mass of gas are inversely proportional provided that the temperature is constant
Charle's law: volume and temperature of a certain mass of gas are directly proportional provided that the pressure is constant
Guy Lussac's law: pressure and temperature of a certain mass of gas are directly proportional provided that the volume is constant

Calculate the ph of a 0.060 m carbonic acid solution, h2co3(aq), that has the stepwise dissociation constants ka1 = 4.3 × 10-7 and ka2 = 5.6 × 10-11.

Answers

1) First dissociation

H2 CO3    =    H(+) + HCO3(-)          Ka1 = 4.3 * 10^ -7

0.06 - x              x          x

Ka1 = x^2 / (0.06 - x) = 4.3 * 10^ - 7

A low Ka => x << 0.06 => 0.06 -x ≈ 0.06

=> Ka1 ≈ x^2 / 0.06 => x^2 ≈ 0.06 * Ka1 = 0.06 * 4.3 * 10^-7

=> x ≈ √[ 2.58 * 10 ^ -8] = 1.606 * 10^ - 4 = 0.0001606

2) Second dissociation

          HCO3(-)    =   H(+) + CO3(2-)         Ka2 = 5.6 * 10^ - 11

0.0001606 - y            y             y

Ka2 ≈ y^2 / 0.0001606 => y = √[0.0001606 * 5.6* 10^ -11]

y = 9.48 * 10^ -8

3) [H+] = x + y = 1.607 * 10^ -4

4) pH = - log [H+] = 3.79

Answer: 3.79
Final answer:

To calculate the pH of a 0.060 M carbonic acid solution, first, consider the first dissociation of the H2CO3. Calculate [H+] by taking the square root of Ka1 x [H2CO3]. Finally, express [H+] in terms of pH. The calculated pH is 3.69.

Explanation:

To calculate the pH of a 0.060 M carbonic acid solution, we have to consider the stepwise dissociation of the carbonic acid, denoted by its dissociation constants Ka1 and Ka2. To see how this works, let's look at the first dissociation of H2CO3:

H2CO3(aq) =  H+(aq) + HCO3- (aq)

Ka1 = [H+][HCO3-]/[H2CO3]

Given, [H2CO3] = 0.060 M and Ka1 = 4.3 × 10-7, we can solve for [H+]. According to the ICE (Initial, Change, Equilibrium) approach, we approximate [H+] by the square root of Ka1 x [H2CO3]. Therefore, [H+] = √(4.3 × 10^-7 × 0.060) = 2.04 x 10^-4. We may ignore the second dissociation (Ka2) as it contributes negligibly to [H+].

Finally, we express [H+] in terms of pH. pH is the negative log to the base 10 of [H+], hence, pH = -log[H+] = -log(2.04 x 10^-4) = 3.69

Learn more about pH calculation here:

https://brainly.com/question/36153729

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The nuclide as-76 has a half-life of 26.0 hours. if a sample of as-76 weighs 344 g, what mass of as-76 remains after 538 minutes?

Answers

The amount of substance after t hours with the given half-life can be calculated through the equation,

                     A(t)  = A(o) x (0.5)^(t/h)

where A(t) is the amount after t hours, A(o) is the original amount, h is the half-life.

Substituting the known values from the given,

It must be noted that the number of minutes should be converted first to hours by dividing it by 60. 

                  A(t) = (344 g) x (0.5)^((538/60)/26))
                       A(t) = 270.86 g
Thus, the amount of as-76 after 538 minutes is approximately 270.86 g. 

The mass of [tex]\(\text{As-76}\)[/tex] remaining after 538 minutes is approximately [tex]\( 270.38 \text{ g} \).[/tex]

To determine the remaining mass of [tex]\(\text{As-76}\)[/tex] after 538 minutes given its half-life of 26.0 hours, we can use the concept of radioactive decay.

First, convert the given time from minutes to hours:

[tex]\[ 538 \text{ minutes} \times \frac{1 \text{ hour}}{60 \text{ minutes}} = 8.97 \text{ hours} \][/tex]

Next, we use the formula for radioactive decay:

[tex]\[ N(t) = N_0 \left( \frac{1}{2} \right)^{\frac{t}{t_{1/2}}} \][/tex]

Plug in the values:

[tex]\( N_0 = 344 \text{ g} \)[/tex][tex]\( t = 8.97 \text{ hours} \)[/tex][tex]\( t_{1/2} = 26.0 \text{ hours} \)[/tex]

Calculate the fraction of the substance remaining after 8.97 hours:

[tex]\[ N(t) = 344 \left( \frac{1}{2} \right)^{\frac{8.97}{26.0}} \][/tex]

First, compute the exponent:

[tex]\[ \frac{8.97}{26.0} \approx 0.344 \][/tex]

Now calculate the remaining mass:

[tex]\[ N(t) = 344 \left( \frac{1}{2} \right)^{0.344} \][/tex]

[tex]\[ N(t) = 344 \times 0.786 \][/tex]

[tex]\[ N(t) \approx 270.38 \text{ g} \][/tex]

So, the mass of [tex]\(\text{As-76}\)[/tex] remaining after 538 minutes is approximately [tex]\( 270.38 \text{ g} \).[/tex]

Compare the temperature dependence of the conductivity for metals and intrinsic semiconductors. briefly explain the difference in behavior

Answers

Conductance decreased when increase in temperature of conductor



But conductance increase when increase in temperature of semiconductor...........

How many carbon atoms are in the longest chain?

Answers

 The answer is 9. The \ / and | are my best representations of the c-c bonds in yahoo. 
Start your numbering from the long chain neartest the bottom of the page and it goes like this: 
1 is very start( the furthest down carbon) 
2 is the only carbon connected to the first carbon \ 
3 is the only carbon connected to the second carbon | 
4 is the only carbon connected to the third carbon \ 
5 is the carbon chain pointing up | 

Then start going right. 
6 is the carbon to the right of 5 / 
7 is the carbon to the right of 6 \ 
8 is the carbon to the right of 7 / 
9 can be either of the 2 single lines coming off of 8( it doesn't matter which one because each will result in a carbon bond with a methyl bond off of it) 

That is all there is too it. My guess is that this is what you did when you got 8 but you forgot to count the very first carbon. I hope this helps.

What is the reducing agent in the following reaction?

2Na + 2H2O → 2NaOH + H2

Answers

Na is the reducing agent since it is being oxidized

Answer: [tex]Na[/tex]

Explanation:

Oxidation reaction : When there is a loss of electrons and thus an increase in oxidation number.

[tex]M\rightarrow M^{n+}+ne^-[/tex]

Reduction reaction : when there is a gain of electrons and thus a decrease in oxidation number.

[tex]M^{n+}+ne^-\rightarrow M[/tex]

Sodium metal has gone under oxidation, as its oxidation state is changing from 0 in [tex]Na[/tex] to +1 in [tex]NaOH[/tex]

[tex]H^+[/tex] ion has gone under reduction, as its oxidation state is changing from +1 in [tex]H^+[/tex] to 0 in [tex]H_2[/tex]

Those chemical agents which get oxidized itself and reduce others is called reducing agents. Thus [tex]Na[/tex] is a reducing agent here.

Which is an endothermic process?


the process in which a substance loses heat energy



the process in which a substance loses kinetic energy



the process in which the molecular motion of a substance decreases



the process in which a substance gains energy


Answers

Answer: Option (d) is the correct answer.

Explanation:

Endothermic process is a process in which energy or heat is absorbed by reactant species.

For example, melting of ice cubes is an endothermic process as it is absorbing heat from the surrounding and gives a cooling effect.

Thus, we can conclude that the process in which a substance gains energy is an endothermic process.

Answer:

The process in which a substance gains energy.

Explanation:

In an endothermic process, a system absorbs energy from the surroundings, therefore increasing its internal energy.

Which is an endothermic process?

the process in which a substance loses heat energy. NO. This is an exothermic process because energy is transferred from the system to the surroundings.the process in which a substance loses kinetic energy. NO. According to the Law of Conservation of Energy, the total energy of an isolated system remains constant, that is, it cannot be created nor destroyed, only transferred and transformed from one form to another. In this case, kinetic energy lost by the substance is gained by the surroundings, so it is an exothermic process.the process in which the molecular motion of a substance decreases. NO. This is connected to the previous option. If molecular motion decreases it is because kinetic energy is being lost and transferred to the environment, in an exothermic process.the process in which a substance gains energy. YES. This coincides with the definition of an endothermic process.

At what temperature will 0.100 molal (M) NaCl(aq) boil?
Kb= 0.51 C kg mol^-1

Answers

The increase of the boling point of a solution is a colligative property.

The formula for the increase of the normal boiling point of water is:

ΔTb = Kb * m

Where m is the molallity of the solution and Kb is the molal boiling constant in °C/mol.

ΔTb = 0.51 °C / m * 0.100 m = 0.051 °C.

So, the new boiling temperature is Tb = 100°C + 0.051°C = 100.051 °C.

Answer: 100.051 °C

A student pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. She then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. The student performs the experiment one more time but this time she stirs the mixture rapidly. In order to get the best results, the student should: A.keep the temperature of the water constant for all three trials B.repeat each trail multiple times C.use the same water container for all three trails D.all of above

Answers

the answer is d all of the above

Answer:

All of the above.

Explanation:

The stirring provides an aid to dissolve. So as compared to a not stirred solution the stirred and vigorously stirred solution will show rapid and more solubility of salt.

In order to study any phenomenon or an experiment we should perform the experiment with same conditions in all the trials. It minimizes the errors.

so we have to keep temperature constant, and the same water container in all the three trials. It gives accuracy to the result

Now the repetition is again required but for precision.

When titrating a strong monoprotic acid and koh at 25°c, the ph will be less than 7 at the equivalence point. ph will be greater than 7 at the equivalence point. titration will require more moles of base than acid to reach the equivalence point. ph will be equal to 7 at the equivalence point. titration will require more moles of acid than base to reach the equivalence point?

Answers

By definition titraion of a monoprotic acid with means that the equivalence point implies netrality of the solution, which is pH = 7.

So, the answer is that pH will be equal to 7 at the equivalence.

Given that the acid is monoprotic and KOH has one OH- radical per molecule of KOH, the titration will require the same number of moles of acid than base to reach the equivalence point, as you can see in this equation, representing the monoprotic acid as HA:

 HA + KOH = K(+) + A(-) + H2O => 1 mol HA per 1 mol KOH.

Answer:

yes

Explanation:

because u right

How many milliliters of 0.100 m naoh are needed to neutralize 50.00 ml of a 0.150 m solution of acetic acid (ch3cooh), a monoprotic acid?

Answers

The neutralization reaction is

NaOH + CH3COOH = Na(+) + CH3COO(-) + H2O

At the neutralization point all the CH3COOH will have reacted, so you are only interested in the reactant ratio:

1 mol of NaOH reacts with 1 mol of CH3COOH.

The formula of molarity is M = n / V => n = M*V

=> M1 * V1 = M2 * V2 => V2 = M1 * V1 / M2

=> V2 = 50.00 ml * 0.150 M / 0.100 M = 75 ml

Answer: 75 ml

Note: M1 = 50.00 ml

          V1 = 0.150 M

         M2 = 0.100 M

Asked: V2?

Answer: First, first realize the reaction:

               NaOH + CH3COOH = Na (+) + CH3COO (-) + H2O

              Second, enter all known numbers into the molarity formula:

                M = n / V

                 n = M * V

                M1 * V1 = M2 * V2

                V2 = M1 * V1 / M2

                V2 = 50.00 ml * 0.150 M / 0.100 M

                V2 = 75 ml

So, the NaOH needed to neutralize 50.00 ml of a solution of 0.1150 m of acetic acid (ch 3 co) is 75 ml.

Further Explanation

In chemistry, molarity (abbreviated M) is one measure of the concentration of the solution. The molarity of a solution expresses the number of moles of a substance per liter of solution. For example, 1.0 liter of solution contains 0.5 mol of compound X, so this solution is called a 0.5 molar (0.5 M) solution. Generally, the concentration of aqueous aqueous solutions is expressed in molar units. The advantage of using molar units is the ease of calculation in stoichiometry because the concentration is expressed in moles (proportional to the actual number of particles). The disadvantage of using this unit is inaccuracy in volume measurement. Also, the volume of a liquid changes with temperature, so the molarity of the solution can change without adding or reducing any substances. Also, in a solution that is not very thin, the molar volume of the substance itself is a function of concentration, so the molarity-concentration relationship is not linear.

A neutralization reaction is a reaction where acids and bases react in aqueous solution to produce salt and water. The liquid sodium chloride that is produced in a reaction is called salt. Salt is an ionic compound consisting of cations from bases and anions from acids. Salt is an ionic compound that is not an acid or a base.

Strong-base Strong Acid Reaction

When the same amount of strong acid such as hydrochloric acid is mixed with a strong base such as sodium hydroxide, the result is a neutral solution. The reaction product does not have the characteristics of either acid or base.

Reactions Involving Weak Acids or Weak Bases

Reactions where at least one component is weak generally do not produce a neutral solution.

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Grade: College

Subject: Chemistry

keywords: molarity

261 nm to millimeters

Answers

the answer is 0.000261 millimeters

In the metric system, a millimeter measures length. The word "milli" is derived from the Latin word "mille," which means one thousandth. A millimeter is therefore one-thousandth of a meter. A millimeter is represented by the letter "mm." Here 261 nm is 0.000261 millimeters.

A nanometer is a length measurement that is one billionth of a meter. The nanometer is denoted by the sign "nm" in the international system of units, sometimes known as SI units. One nanometer can be represented as 1 x 10⁻⁹ meters in scientific notation.

Here,

1 mm = 1000000 nm

261 nm = 0.000261 mm

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0.000261 millimeters

Matter is neither created nor destroyed in a chemical reaction

Answers

This is true according to the Law of Conservation of Mass.

Hope this helps! :)

Write the net ionic equation for the equilibrium that is established when potassium hypochlorite is dissolved in water.

Answers

Final answer:

When potassium hypochlorite is dissolved in water, it dissociates into potassium ions and hypochlorite ions. Thus, the net ionic equation for this process is: KClO(s) -> K+(aq) + ClO-(aq).

Explanation:

The net ionic equation represents the actual reaction happening in solution, excluding the spectator ions. When potassium hypochlorite (KClO) is dissolved in water, it dissociates completely into potassium ions (K+) and hypochlorite ions (ClO-).

So, the complete ionic equation is: KClO(s) -> K+(aq) + ClO-(aq).

The net ionic equation is the same as the complete ionic equation because there are no spectator ions in this case. Thus, the net ionic equation for the equilibrium that is established when potassium hypochlorite is dissolved in water is: KClO(s) -> K+(aq) + ClO-(aq)

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The net ionic equation for the equilibrium established when potassium hypochlorite dissolves in water involves only the hypochlorite ion reacting with water to form hypochlorous acid and hydroxide ion.

When potassium hypochlorite (KClO) is dissolved in water, it dissociates into potassium (K+) ions and hypochlorite (ClO-) ions.

Potassium is a spectator ion and does not participate in the equilibrium reaction that is established in the solution. Therefore, the net ionic equation for the equilibrium when potassium hypochlorite is dissolved in water only involves the hypochlorite ion and water.

The equation is as follows:

ClO-(aq) + H2O(l) ---> HClO(aq) + OH-(aq)

This equation represents the equilibrium between the hypochlorite ion and the hypochlorous acid and hydroxide ion in aqueous solution.

Mercury has an atomic mass of 200.59 amu. calculate the mass of 3.0 x 10^10 atoms

Answers

To determine mass of the given number of atoms of mercury, we need a factor that would relate the number of atoms to number of moles. In this case, we use the Avogadro's number. It is a number that represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. The number of units could be atoms, molecules, ions or electrons. To convert into mass, we use the given amu of mercury since it is equal to grams per mole. We calculate as follows:

3.0 x 10^10 atoms ( 1 mol / 6.022 x 10^23 atoms ) ( 200.59 g / 1 mol ) = 9.99x10^-12 g Hg
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