Chemistry Answers

Calculate the Standard Gibbs free energy change for the following reaction at 25 degree celcius.

CaCO₃ + 2HCI(g) > CaCI₂(s) + CO₂(g) + H₂O(I)

ΔG⁰_f (kJ/mol) 1129 -95.3 -750.2 -394.4 -237.2

Solve the following problems.

1. A voltaic cell is based on a Co2+ /Co half-cell and an AgCl/Ag half-cell.

a. What reaction occurs at the anode?

b. What is the standard cell potential?

2. Using the standard reduction potentials, calculate the standard emf for each of the following reactions:

a. 2Al3+ + 3Cd ⟶ 2Al + 3Cd2+

b. Cr + 2Cr3+⟶3Cr2+

c. H2 + I2 ⟶ 2H+ + 2I

Determine if each of the following redox reactions is spontaneous or not.

1. Cu + 2Ag+ ⟶ Cu2+ + 2Ag

2. Al3+ + Fe ⟶ Al + Fe2+

3. Zn + Ni2+ ⟶ Zn2+ + Ni

4. 3Pb + 2Au3+ ⟶ 3Pb2+ + 2Au

5. Hg + Pb2+⟶ Hg2+ + Pb

Determine if each of the following redox reactions is spontaneous or not.

1. Cu + 2Ag+ ⟶ Cu2+ + 2Ag

2. Al3+ + Fe ⟶ Al + Fe2+

3. Zn + Ni2+ ⟶ Zn2+ + Ni

4. 3Pb + 2Au3+ ⟶ 3Pb2+ + 2Au

5. Hg + Pb2+⟶ Hg2+ + Pb

AH-453 kJ/mol-rxn P4010(S) + 6H₂O(1)-4H3PO4(aq) How many grams of P4010(S) would have to react to produce 167 kJ of energy?

The metals in Group IIIA, IVA and VA of the periodic table are not transition metals. However, all but 1 have variable charges. What element in Group IIIA, Period 3 has a fixed charge, and what is that charge?

What is the PH of a solution whose hydroxide

-3

ion (OH) is 0.003 moldm

How can you separate a mixture of salt, sand and water, stating the technique or principle of the separation?

Which of the following statement(s) about atoms is/are correct?

a. Atoms compose matter

b. Atoms are the basic building block of nature

c. All of the above statements are true

d. An atom is the smallest identifiable unit of an element

How is Dalton's law illustrated in experiment evaluation of the Gas Law constant?