Chemistry, 25.07.2020 06:01 NikolaiSolokov

You are given 10.00 mL of a solution of an unknown acid. The pH of this solution is exactly 2.18. You determine that the concentration of the unknown acid was 0.2230 M. You also determined that the acid was monoprotic (HA). What is the pKa of your unknown acid

Answers: 3

Show answers

Answers

Answer from: myaaa13754

pKa=3.70

Explanation:

Hello,

In this case, given the information, we can compute the concentration of hydronium given the pH:

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

$[H^+]=10^{-pH}=10^{-2.18}=6.61x10^{-3}M$

Next, given the concentration of the acid and due to the fact it is monoprotic, its dissociation should be:

$HA\rightleftharpoons H^++A^-$

We can write the law of mass action for equilibrium:

$Ka=\frac{[H^+][A^-]}{[HA]}$

Thus, due to the stoichiometry, the concentration of hydronium and A⁻ are the same at equilibrium and the concentration of acid is:

$[HA]=0.2230M-6.61x10^{-3}M=0.2164M$

As the concentration of hydronium also equals the reaction extent (). Thereby, the acid dissociation constant turns out:

$Ka=\frac{(6.61x10^{-3})^2}{0.2164}\\ \\Ka=2.02x10^{-4}$

And the pKa:

$pKa=-log(Ka)=-log(2.02x10^{-4})\\\\pKa=3.70$

Regards.

Answer from: Quest

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

Write 15 uses of a mercury barometer along with its characterestics

Answer from: Quest

answer: a tank of height h is filled with water and sits on the ground. water squirts from a hole at a height y above the ground and has a range r. for two y values, 0 and h, r is zero. determine the value of y for which the range will be a maximum.

explanation: