For each image, select the state of matter represented.

Your job is to determine the concentration of ammonia in a commercial window cleaner. In the titration of a 25.0 mL sample of th

ruslelena [56]

Answer:

The initial concentration of ammonia is 0.14 M and the pH of the solution at equivalence point is 5.20

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$ .....(1)

Molarity of HCl solution = 0.164 M

Volume of solution = 23.8 mL = 0.0238 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$0.164M=\frac{\text{Moles of HCl}}{0.0238L}\\\\\text{Moles of HCl}=(0.146mol/L\times 0.0238L)=0.0035mol$

The chemical equation for the reaction of ammonia and HCl follows:

$NH_3+HCl\rightarrow NH_4^++Cl^-$

By Stoichiometry of the reaction:

1 mole of HCl reacts with 1 mole of ammonia

So, 0.0035 moles of HCl will react with = $\frac{1}{1}\times 0.0035=0.0035mol$ of ammonia

Calculating the initial concentration of ammonia by using equation 1:

Moles of ammonia = 0.0035 moles

Volume of solution = 25 mL = 0.025 L

Putting values in equation 1, we get:

$\text{Initial concentration of ammonia}=\frac{0.0035mol}{0.025L}=0.14M$

By Stoichiometry of the reaction:

1 mole of ammonia produces 1 mole of ammonium ion

So, 0.0035 moles of ammonia will react with = $\frac{1}{1}\times 0.0035=0.0035mol$ of ammonium ion

Calculating the concentration of ammonium ion by using equation 1:

Moles of ammonium ion = 0.0035 moles

Volume of solution = [23.8 + 25] mL = 48.8 mL = 0.0488 L

Putting values in equation 1, we get:

$\text{Molarity of ammonium ion}=\frac{0.0035mol}{0.0488L}=0.072M$

To calculate the acid dissociation constant for the given base dissociation constant, we use the equation:

$K_w=K_b\times K_a$

where,

$K_w$ = Ionic product of water = $10^{-14}$

$K_a$ = Acid dissociation constant

$K_b$ = Base dissociation constant = $1.8\times 10^{-5}$

$10^{-14}=1.8\times 10^{-5}\times K_a\\\\K_a=\frac{10^{-14}}{1.8\times 10^{-5}}=5.55\times 10^{-10}$

The chemical equation for the dissociation of ammonium ion follows:

$NH_4^+\rightarrow NH_3+H^+$

The expression of $K_a$ for above equation follows:

$K_a=\frac{[NH_3][H^+]}{[NH_4^+]}$

We know that:

$[NH_3]=[H^+]=x$

$[NH_4^+]=0.072M$

Putting values in above expression, we get:

$5.55\times 10^{-10}=\frac{x\times x}{0.072}\\\\x=6.32\times 10^{-6}M$

To calculate the pH concentration, we use the equation:

$pH=-\log[H^+]$

We are given:

$[H^+]=6.32\times 10^{--6}M$

$pH=-\log (6.32\times 10^{-6})\\\\pH=5.20$

Hence, the initial concentration of ammonia is 0.14 M and the pH of the solution at equivalence point is 5.20

5 0

2 years ago

Where does secretion occur in the nephron?

grin007 [14]

Inside the glomerular capsule at the glomerulus

7 0

2 years ago

Potassium and fluorine are both halogens?

andreev551 [17]

Answer:

false, Potassium and fluorine are not halogens.

only fluorine here is halogen.

potassium is an alkali earth metal it doesn't comes under category of halogens, but fluorine

is a non metal which comes under halogen family.

7 0

2 years ago

At a consent tempture the pressure on a 2.5 l ballon is increased from 2.4 atm to 5.8 atm. what is the new volume?

marissa [1.9K]

Answer:

1.034 L

Explanation:

P1 V1 = P2 V2

P1 V1 / P2 = V2

2.4 (2.5) / 5.8 = V2 = 1.034 L

8 0

1 year ago

PLZ HELP I DONT KNOW HOW TO DO THIS!!!

koban [17]

#1 The Correct Answer is D

D) The Distance Traveled by The Wave During One Full Cycle.

Ex. frequency, wavelength, amplitude and wave speed. Amplitude is measured in metres (m). The greater the amplitude of a wave then the more energy it is carrying. The wavelength, λ, of a wave is the distance from any point on one wave to the same point on the next wave along.

(The symbol is a Greek letter, 'lambda'.)


#2 The Correct Answer is B

B) Police Siren

Ex.Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave. Slinky waves, water waves, stadium waves, and jump rope waves are other examples of mechanical waves; each requires some medium in order to exist.

7 0

3 years ago