Hello :)
Based on the information I received reading the picture, the answer should be “B”
Explanation: if I am wrong I’m very sorry. But that should be the answer
Answer:
Q = 2647 J
Explanation:
Specific heat capacity is the amount of energy required by one Kg of a substance to raise its temperature by 1 °C.
In thermodynamics the equation used is as follow,
Q = m Cp ΔT
Where;
Q = Heat = ?
m = mass = 660 g
Cp = Specific Heat Capacity = 0.3850 J.g⁻¹.°C⁻¹
ΔT = Change in Temperature = 23.35 °C - 12.93 °C = 10.42 °C
Putting values in eq. 1,
Q = 660 g × 0.3850 J.g⁻¹.°C⁻¹ × 10.42 °C
Q = 2647 J
Answer:
C. CH3COOH, Ka = 1.8 E-5
Explanation:
analyzing the pKa of the given acids:
∴ pKa = - Log Ka
A. pKa = - Log (1.0 E-3 ) = 3
B. pKa = - Log (2.9 E-4) = 3.54
C. pKa = - Log (1.8 E-5) = 4.745
D. pKa = - Log (4.0 E-6) = 5.397
E. pKa = - Log (2.3 E-9) = 8.638
We choose the (C) acid since its pKa close to the expected pH.
⇒ For a buffer solution formed from an acid and its respective salt, we have the equation Henderson-Hausselbach (H-H):
- pH = pKa + Log ([CH3COO-]/[CH3COOH])
∴ pH = 4.5
∴ pKa = 4.745
⇒ 4.5 = 4.745 + Log ([CH3COO-]/[CH3COOH])
⇒ - 0.245 = Log ([CH3COO-]/[CH3COOH])
⇒ 0.5692 = [CH3COO-]/[CH3COOH]
∴ Ka = 1.8 E-5 = ([H3O+].[CH3COO-])/[CH3COOH]
⇒ 1.8 E-5 = [H3O+](0.5692)
⇒ [H3O+] = 3.1623 E-5 M
⇒ pH = - Log ( 3.1623 E-5 ) = 4.5
Answer:
Explanation:
When a salt is dissolved , it increases the boiling point . Increase in boiling point depends upon number of ions . So it is a colligative property .
.19 m AgNO₃ . Each molecule will ionize into two ions . So effective molar concentration is 0.19 x 2 = .38 m
0.17 m CrSO4.Each molecule will ionize into two ions . So effective molar concentration is 0.17 x 2 = .34 m
0.13 m Mn(NO₃)₂. Each molecule will ionize into three ions . So effective molar concentration is 0.13 x 3 = .39 m
0.31 m Sucrose(nonelectrolyte). Molecules will not ionize . So effective molar concentration is 0.31 x 1 = .31 m
Higher the molar concentration , greater the depression in boiling point .
So lowest boiling point is 0.13 m Mn(NO₃)₂.
second highest boiling point is 0.19 m AgNO3.
Third lowest boiling point is 0.17 m CrSO4
Highest boiling point or lowest depression 0.31 m Sucrose.
a . 4
b . 1
c . 2
d . 3
