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The compound methylamine, CH3NH2, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibrium

Veronika [31]

Answer:

Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]

Explanation:

According to Brönsted-Lowry acid-base theory:

An acid is a substance that donates H⁺.
A base is a substance that accepts H⁺.

When methylamine reacts with water, it behaves as a Brönsted-Lowry base, according to the following reaction.

CH₃NH₂(aq) + H₂O(l) ⇄ CH₃NH₃⁺(aq) + OH⁻(aq)

The basic equilibrium constant (Kb) is:

Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]

3 0

3 years ago

An analytical chemist is titrating of a solution of propionic acid with a solution of 224.9 ml of a 0.6100M solution of propioni

Svetllana [295]

Answer: The pH of acid solution is 4.58

Explanation:

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

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}$ .....(1)

For KOH:

Molarity of KOH solution = 1.1000 M

Volume of solution = 41.04 mL

Putting values in equation 1, we get:

$1.1000M=\frac{\text{Moles of KOH}\times 1000}{41.04}\\\\\text{Moles of KOH}=\frac{1.1000\times 41.04}{1000}=0.04514mol$

For propanoic acid:

Molarity of propanoic acid solution = 0.6100 M

Volume of solution = 224.9 mL

Putting values in equation 1, we get:

$0.6100M=\frac{\text{Moles of propanoic acid}\times 1000}{224.9}\\\\\text{Moles of propanoic acid}=\frac{0.6100\times 224.9}{1000}=0.1372mol$

The chemical reaction for propanoic acid and KOH follows the equation:

$C_2H_5COOH+KOH\rightarrow C_2H_5COOK+H_2O$

Initial: 0.1372 0.04514

Final: 0.09206 - 0.04514

Total volume of solution = [224.9 + 41.04] mL = 265.94 mL = 0.26594 L (Conversion factor: 1 L = 1000 mL)

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{salt}]}{[acid]})$

$pH=pK_a+\log(\frac{[C_2H_5COOK]}{[C_2H_5COOH]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of propanoic acid = 4.89

$[C_2H_5COOK]=\frac{0.04514}{0.26594}$

$[C_2H_5COOH]=\frac{0.09206}{0.26594}$

pH = ?

Putting values in above equation, we get:

$pH=4.89+\log(\frac{(0.04514/0.26594)}{(0.09206/0.26594)})\\\\pH=4.58$

Hence, the pH of acid solution is 4.58

7 0

4 years ago

Washing machines use a large amount of water. A student suggested that old pairs of stained jeans which have to be washed more f

sukhopar [10]

Answer:

C |||| It is not practical because it takes a huge amount of water to produce a new pair of jeans

Explanation:

If you're doing flvs then it's C.

5 0

3 years ago

Read 2 more answers

Simply parmanent tissue real life application please help it's for my project

WITCHER [35]

The simple tissues are parenchyma, sclerenchyma and collenchyma. Chlorenchyma is a parenchyma, having chloroplast. It is a simple permanent tissue, having chloroplast.

8 0

3 years ago

You have 55 grams of glucose(C6H12O6). How many grams of oxygen do you have?

zubka84 [21]

Answer:

Mass of oxygen in glucose = 29.3g

Explanation:

Mass of glucose given is 55grams.

We are to find the mass of oxygen in this compound.

In the compound we have 6 atoms of oxygen.

Solution

To find the mass of oxygen in glucose, we calculate the formula mass of glucose. We now divide the formula mass of the oxygen atom with that of the glucose and multiply by the given mass to find the unkown mass.

Atomic mass of C = 12g

H = 1g

O = 16g

Formula mass of C₆H₁₂O₆ = {(12x6) + (1x12) + (16x6)} = 180

Mass of O in glucose = $\frac{6x16}{180}$ x 55

= $\frac{96}{180}$ x 55

= 0.53 x 55

Mass of oxygen in glucose = 29.3g

8 0

3 years ago