All categories

3 years ago

A buffer is prepared containing 0.75 M NH3 and 0.20 M NH4 . Calculate the pH of the buffer using the Kb for NH3. g

Chemistry

1 answer:

denis-greek [22]3 years ago

3 0

Answer:

pH=8.676

Explanation:

Given:

0.75 M $NH_{3}$

0.20 M $NH_{4}$

The objective is to calculate the pH of the buffer using the kb for $NH_3$

Formula used:

$pOH=pka+log\frac{[salt]}{[base]}\\$

pH=14-pOH

Solution:

On substituting salt=0.75 and base=0.20 in the formula

$pOH=-log(1.77*10^{-5})+log\frac{0.75}{0.20}\\ =4.75+0.5740\\ =5.324$

pH=14-pOH

On substituting the pOH value in the above expression,

pH=14-5.324

Therefore,

pH=8.676

You might be interested in

A metal melts at 450 degrees celsius. Is this property of the metal classified as chemical or physical?

Romashka-Z-Leto [24]

It's a physical property because it doesn't change the element of the metal.
does this make sense?

8 0

3 years ago

How many milliliters of a 0.285 M HCl solution are needed to neutralize 249 mL of a 0.0443 M Ba(OH)2 solution?

meriva

Answer:

$\large \boxed{\text{77.4 mL}}$

Explanation:

Ba(OH)₂ + 2HCl ⟶ BaCl₂ + H₂O

V/mL: 249

c/mol·L⁻¹: 0.0443 0.285

1. Calculate the moles of Ba(OH)₂

$\text{Moles of Ba(OH)$_{2}$} = \text{0.249 L Ba(OH)}_{2} \times \dfrac{\text{0.0443 mol Ba(OH)}_{2}}{\text{1 L Ba(OH)$_{2}$}} = \text{0.011 03 mol Ba(OH)}_{2}$

2. Calculate the moles of HCl

The molar ratio is 2 mol HCl:1 mol Ba(OH)₂

$\text{Moles of HCl} = \text{0.011 03 mol Ba(OH)}_{2} \times \dfrac{\text{2 mol HCl}}{\text{1 mol Ba(OH)}_{2}} = \text{0.022 06 mol HCl}$

3. Calculate the volume of HCl

$V_{\text{HCl}} = \text{0.022 06 mol HCl} \times \dfrac{\text{1 L HCl}}{\text{0.285 mol HCl}} = \text{0.0774 L HCl} = \textbf{77.4 mL HCl}\\\\\text{You must add $\large \boxed{\textbf{77.4 mL}}$ of HCl.}$

8 0

3 years ago

The volume of a gas at 2.0 atm is 3.0 L. What is the volume of the gas at 1.5 atm at the same temperature?

pshichka [43]

Answer:

4 L

Explanation:

Ideal gas law is P1V1T2=P2V2T1

V2=P1V1/P2

T is not necessary to add since it is constant.

6 0

2 years ago

Five gases combined in a gas cylinder have the following partial pressures: 3. 00 atm (N2), 1. 80 atm (O2), 0. 29 atm (Ar), 0. 1

Helen [10]

The total pressure of the gaseous mixture has been 5.37 atm. Thus, option D is correct.

The partial pressure has been defined as the pressure exerted by each gas in the mixture.

According to the Dalton's law of partial pressure, the total pressure of gas has been the sum of the partial pressure of the gases in the mixture.

The given partial pressure of gases in the mixture has been: