What mass of benzoic acid would you dissolve in 350.0 mL of water to produce a solution with a pH = 2.85?

The mass of the benzoic acid involved is 1.3 g.

What is pH?

The pH shows the degree of acidity or alkalinity of the solution. We have been told that the pH of this solution is 2.85. We have the reaction;

C6H5COOH ⇄C6H5COO- + H^+

Ka = [C6H5COO-] [H^+]/[C6H5COOH]

[H^+] = Antilog (-2.85) = 1.4 * 10^-3 M

6.3 x 10-5 = [1.4 * 10^-3]^2/ [C6H5COOH]

[C6H5COOH]  =  [1.4 * 10^-3]^2/ 6.3 x 10-5

[C6H5COOH]  = 1.96 * 10^-6/6.3 x 10-5

= 3.1 * 10^-2 M

number of moles = concentration * volume

number of moles = mass/molar mass

mass/molar mass = concentration * volume

mass = concentration * volume * molar mass

mass = 3.1 * 10^-2 M * 0.35 L * 122 g/mol

mass = 1.3 g

14.1391 g

Explanation:

The pH of a solution is defined as the negative of the hydrogen ion's concentration.

Thus,

pH = - log [H⁺]

Given that:

pH = 2.85

2.85 = - log [H⁺]

So,

[H⁺] = 0.0014125 M

Also, benzoic acid exists in equilibrium in water as:

C₆H₅COOH ⇄ C₆H₅COO⁻ + H⁺   Ka = 6.3×10⁻⁵

The ICE table is:

C₆H₅COOH ⇄ C₆H₅COO⁻ + H⁺

At t = 0             a                        0             0

At t = teq         a-x                        x            x

The expression for Ka is:

Ka = 6.3×10⁻⁵ = [C₆H₅COO⁻][H⁺] / [C₆H₅COOH]

Also,

6.3×10⁻⁵ = x.x / (a-x)

x = [H⁺] = 0.0014125 M

6.3×10⁻⁵ = (0.0014125)² / (a-0.0014125)

Solving, a = 0.3308 M

Given volume = 350.0 mL = 350.0×10⁻³ L

So, Moles of benzoic acid = Concentration×Volume

Moles = 0.3308×350.0×10⁻³ = 0.11578 moles

Mass = Molar mass × moles

Molar mass of benzoic acid = 122.12 g/mol

So,

Mass = 122.12 g/mol × 0.11578 moles = 14.1391 g

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What is the waste product of photosynthesis?
a. O2
b. CO2
c. H2O
d. C6H12O6

Answer : The correct option is, (a)

Explanation :

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During photosynthesis process, the carbon dioxide reacts with water in the presence of sunlight to gives glucose and oxygen as a byproduct.

In the photosynthesis reaction, carbon dioxide and water molecule are the reactants and glucose and oxygen are the products.

The balanced chemical reaction will be,

From the balanced reaction we conclude that the carbon dioxide and water are the reactants which are present on the left side in a reaction and glucose and oxygen are the products which are present on the right side in the reaction.

Hence, in the photosynthesis the waste product is .

Plants produce oxygen.  So the answer is A. O2

Which property of an unsaturated solution of sodium chloride in water remains the same when more water is added to the solution? (1) density of the solution (2) boiling point of the solution (3) mass of sodium chloride in the solution (4) percent by mass of water in the solution

(3)Mass of Sodium Chloride in the solution

What volume is equivalent to 12.0 m3?

i think 12000 is the answer

A compound decomposes by a first-order process. if 25.0% of the compound decomposes in 60.0 minutes, the half-life of the compound is _________. a. 65 minutes
b. 198 minutes
c. 120 minutes
d. 145 minutes
e. 180 minutes

Half-life is the time needed for a radioactive to decay half of its weight. The formula to find the half-life would be:

Nt= N0 (1/2)^ t/h

Nt= the final mass
N0= the initial mass
t= time passed
h= half-life

If 25.0% of the compound decomposes that means the final mass would be 75% of initial mass. Then the half-live for the compound would be:
Nt= N0 (1/2)^ t/h
75%= 100% * (1/2)^ (60min/h)
3/4= 1/2^(60min/h)
log2 3/4 = log2 1/2^(60min/h)
0.41503749928 = -60min/h
h= -60 min / 0.41503749928= 144.6min

3) Explain the difference between CO2 and C204.