Chemistry, 28.07.2019 07:00 elysabrina6697

Calculate the ph after 0.020 mol hcl is added to 1.00 l of each of the four solutions below.

Answers: 1

Show answers

Answers

Answer from: Jacques1b

The pH of the solutions after adding 0.02mol of HCl will be 1.7, 1.69, 1.7, and 6.4 respectively.

pH is used to measure the alkalinity and acidity of the solutions. pH 7 is neutral.

For solution A,

$\bold {Kb =\dfrac {[OH^-][HONH3+]}{[NH2OH]} }$

put the value and solve it for [OH]

$\bold {[OH^-] = 6.6x10^-^5 M }$

$\bold{ pOH = -log[OH]}\\\\\bold{ pOH = -log(6.6x10^-^5)}\\\\\bold {pOH = 4.18}}\\$

Since, pH = 14 - pOH

pH = 9.82

Since, $\bold{[H^+] = 0.02}$

$\bold {pH = -log (0.02)}\\\bold {pH = 1.7}$

For Solution B

$\bold {Ka [HONH_3Cl ]= 9.09x10^-7 }\\\\\bold {Ka = \dfrac { [H+][HONH2]} { [HONH3+]}}$

Since, $\bold { [H^+] = 6x10^-^4 }$

So, pH = $\bold {pH = -log (6x10^-4) = 3.22}$

The new pH will be

$\bold {pH = -log (6x10^-4+0.02)}\\\bold {pH = 1.69}$

$\bold{[H^+] = 0.02}\\\bold {pH = -log (0.02)}\\\bold {pH = 1.7}$

(D) Since, $\bold {HONH_2}$ and $\bold {HONH_3Cl}$ are at same concentration.

So, $\bold {pH = pKa}$

$\bold {Pka = -log Ka}\\\\\bold {pKa = -log 9.09x10^-7}\\\\\bold{ pKa = 6.04}\\\\\bold{ pH = 6.04}$

Therefore, The pH of the solutions after adding 0.02mol of HCl will be 1.7, 1.69, 1.7, and 6.4 respectively.

To know more about pH

link

Answer from: meiyrarodriguez

A) according to this reaction:
by using ICE table:
NH2OH(aq) + H2O(l) → HONH3+(aq) + OH-
initial 0.4 M 0 0
change -X +X +X
Equ (0.4-X) X X

when Kb = [OH-][HONH3+]/[NH2OH]
when we have Kb = 1.1x10^-8 so,
by substitution:
1.1x10^-8 = X^2/(0.4-X) by solving this equation for X

∴X = 6.6x10^-5 M
∴[OH] = 6.6x10^-5 M
when POH = - ㏒[OH]
∴POH = -㏒(6.6x10^-5)= 4.18
∴PH = 14 - POH = 14 - 4.18
= 9.82
when PH = -㏒[H+]
∴[H+] = 10^9.82 = 1.5x10^-10 M+0.02molHcl
= 0.02
∴ the new value of PH = -㏒(0.02)
∴PH = 1.7

B) according to this reaction:
by using ICE table:
HONH3+(aq) → H+(aq) + HONH2(aq)
intial 0.4 0 0
change -X +X +X
Equ (0.4-X) X X

when Ka HONH3Cl = 9.09x10^-7
and Ka = [H+][HONH2] / [HONH3+]

So by substitution and we can assume [HONH3+] = 0.4 as the value of Ka is so small so,
9.09x10^-7 = X^2 / 0.4 by solving for X
∴ X = 6 x 10 ^-4
∴[H+] = 6x10^-4
PH = -㏒[H+]
= -㏒ (6x10^-4) = 3.22
when [H+] = 6x10^-4 + 0.02 m HCl
∴new value of PH = -㏒(6x10^-4+0.02)
= 1.69
C) when we have pure H2O and PH of water = 7
So we can get [H+] when PH = -㏒[H+]
∴[H+] = 10^-7 + 0.02MHCl
= 0.02
∴new value of PH = -㏒0.02
PH = 1.7
d) when HONH2 & HONH3Cl have the same concentration and Hcl added to them so we can assume that PH=Pka
and when we have Ka for HONH3Cl = 9.09x10^-7
So we can get the Pka:

Pka = -㏒Ka
= -㏒9.09x10^-7
= 6.04
∴PH = 6.04
and because of the concentration of the buffer components, HONH2 & HONH3Cl have 0.4 M and the adding of HCl = 0.02 M So PH will remain very near to 6

Answer from: Quest

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."

Answer from: Quest

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary

Another question on Chemistry

Chemistry, 22.06.2019 09:00

Astudent is asked to identify and element that is pale yellow brittle solid and does not conduct electricity. at which location in this periodic table would the element most likely be found?

Answers: 2

Answer

Chemistry, 22.06.2019 18:30

How many moles of bromine are needed to produce 3.23 moles of potassium bromide

Answers: 1

Answer

Chemistry, 22.06.2019 22:30

Why is the bottom layer of a trophic pyrimid the

Answers: 2

Answer

Chemistry, 23.06.2019 01:00

Which statement best describes isomers? a. isomers are alcohols that have the same functional group. b. isomers have at least one carbon-carbon double bond. c. isomers have the same molecular formula but different structural properties.

Answers: 1

Answer

You know the right answer?

Calculate the ph after 0.020 mol hcl is added to 1.00 l of each of the four solutions below....

Questions