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2 years ago

Help I don’t know the answer

Mathematics

1 answer:

Marrrta [24]2 years ago

6 0

Answer:

15 ft

Step-by-step explanation:

cause

24/8=3

5×3=15

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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

PLEASE HELP ASAP!!! CORRECT ANSWERS ONLY PLEASE!!!

balu736 [363]

x equals 4 and y equals 5 . so the formula would be 5x+12y=80 and if we need 4 of the small boxes we sub x for 4 and we get 5(4) =20. Next, 80 minus 20 is 60, and the equation would now be 12y=60. we now divide both sides by 12 and we get left with y=5. 5x + 12y = 80 5(4) + 12(5)=80 20+60=80. That is all. I hope that doesn't sound confusing

5 0

3 years ago

Lettets a, b, c, and d are angle measures Which should equal 105 to prove false g

GrogVix [38]

Answer:

a equals 105°

Step-by-step explanation:

angles in a straight line add up to 180°

a+75=180

a=180-75

a=105°

4 0

3 years ago

3.006 rounded to the nearest tenth

Ann [662]

3.006 rounded to the nearest tenth is 3.0. This is due to the fact that the 6 rounded up will mean that the current 0 becomes 1, but this will not be carried to the tenth when rounding up.

3 0

3 years ago

Read 2 more answers

20 points and Brainliest if answered and explained!

Rasek [7]

What you need to know for this case is that the sum of the internal angles of a triangle is 180 °
We then have the following equation that is given by:
(2x) + (3x) + (4x) = 180
Clearing x we have:
9x = 180
x = 180/9
x = 20
Therefore we have:
m∠A = (40) °
m∠B = (60) °
m∠C = (80) °
Answer:
B) m∠B = 60 °

6 0

3 years ago