The minimum wage is increased by 1.7%. It was originally £6.10. How much is the minimum wage now?

Calculate the pH of a buffer solution made by mixing 300 mL of 0.2 M acetic acid, CH3COOH, and 200 mL of 0.3 M of its salt sodiu

Lesechka [4]

Answer:

Approximately $4.75$ .

Step-by-step explanation:

Remark: this approach make use of the fact that in the original solution, the concentration of $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ are equal.

${\rm CH_3COOH} \rightleftharpoons {\rm CH_3COO^{-}} + {\rm H^{+}}$

Since $\rm CH_3COONa$ is a salt soluble in water. Once in water, it would readily ionize to give $\rm CH_3COO^{-}$ and $\rm Na^{+}$ ions.

Assume that the $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ ions in this solution did not disintegrate at all. The solution would contain:

$0.3\; \rm L \times 0.2\; \rm mol \cdot L^{-1} = 0.06\; \rm mol$ of $\rm CH_3COOH$ , and

$0.06\; \rm mol$ of $\rm CH_3COO^{-}$ from $0.2\; \rm L \times 0.3\; \rm mol \cdot L^{-1} = 0.06\; \rm mol$ of $\rm CH_3COONa$ .

Accordingly, the concentration of $\rm CH_3COOH$ and $\rm CH_3COO^{-}$ would be:

$\begin{aligned} & c({\rm CH_3COOH}) \\ &= \frac{n({\rm CH_3COOH})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}$ .

$\begin{aligned} & c({\rm CH_3COO^{-}}) \\ &= \frac{n({\rm CH_3COO^{-}})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}$ .

In other words, in this buffer solution, the initial concentration of the weak acid $\rm CH_3COOH$ is the same as that of its conjugate base, $\rm CH_3COO^{-}$ .

Hence, once in equilibrium, the $\rm pH$ of this buffer solution would be the same as the ${\rm pK}_{a}$ of $\rm CH_3COOH$ .

Calculate the ${\rm pK}_{a}$ of $\rm CH_3COOH$ from its ${\rm K}_{a}$ :

$\begin{aligned} & {\rm pH}(\text{solution}) \\ &= {\rm pK}_{a} \\ &= -\log_{10}({\rm K}_{a}) \\ &= -\log_{10} (1.76 \times 10^{-5}) \\ &\approx 4.75\end{aligned}$ .

7 0

3 years ago

Express 80 as the product of its prime factors.<br> Write the prime factors in ascending order.

stepan [7]

Answer:

the answer of that is 16 x 5

Step-by-step explanation:

7 0

2 years ago

HELP ASAP BEING TIMED! If Triangle J K L is congruent to Triangle B C A, which statement must be true?

Vlada [557]

Answer:

Choice C

Step-by-step explanation:

This is like a matching question. Here's what I mean by this. We know Triangle BCA and Triange JKL are congruent. So, what we have to do is match the side lengths together.

So the first side of BCA matches with JKL, the second side of BCA matches with JKL, the third side of BCA matches with JKL.

So first side:

BC is congruent to JK

So second side:

CA is congruent to KL

So third side:

JL is congruent to BA

The third side is one of our answer choices.

That answer choice is C.

3 0

2 years ago

0 A pigeon can fly at a speed of 84 kilometers per hour. How long does it take the pigeon to fly 7 kilometers

QveST [7]

The miles per hour is 84 kilometers per 60 minutes (7:5 ratio) so if we take seven kilometers times the ratio 5/7 we get 5 minutes

7 0

3 years ago

The square root of -12 × the square root of -9 (THIS IS AN ALGEBRA 2 QUESTION)

nlexa [21]

Answer:

$\sqrt{-12} = 2\sqrt{3} i\\\sqrt{-9}= 3i\\3i * 2\sqrt{3}i = -6\sqrt{3$

Step-by-step explanation:

5 0

3 years ago