Silver tarnish (Ag_2S) can be removed by immersing silverware in a hot solution

Question

Silver tarnish (Ag_2S) can be removed by immersing silverware in a hot solution of baking soda (NaHCO_3) in a pan lined with aluminum foil; however, foul-smelling hydrogen sulfide gas (H_2S) is produced. Which one of the following reactions does not represent part or all of what is happening? When the volume of a gas is increased, the energy separation between microstates increases. remains unchanged decreases becomes infinite. disappears. Given the following data, determine the rate law for the reaction

Explanation / Answer

1. Reaction a) and e) do not occur in the process of removing of silver tarnish.

Explanation- Only following chemical reactions is occurring.

3 Ag2S(s) + 2 Al(s) + 3 H2O 6 Ag(s) + Al2O3(s) +3 H2S

The reaction itself is actually an electrochemical reaction – essentially, tiny electric current flows between the silver and the aluminium when they are in contact, and the silver in silver sulphide is reduced to form Ag, whilst the aluminium is oxidized to form Al3+ ion

3 Ag+ + 3 e– 3 Ag

Al Al3+ + 3e

Combining these two half equations gives us the full redox equation for the reaction-

Al + 3 Ag+ Al3+ + 3 Ag

2. Option a) when the volume of gas increased, the energy separation between microstates increases.

Explanation-The larger the volume available to the gas, the greater the number of microstates its thermal energy can occupy.

3. Option d) is correct.

Explanation NH4+(aq) + NO2-(aq) ---------à N2(g) + 2 H2O(l)

Rate = k[NH4+]n[NO2-]m

In Experiment 1 and 3rate doubles when concentration of NO2- doubles

m = 1 (first order)

Experiment 2 and 3 rate doubles when concentration of NH4+ doubles

n = 1 (first order)

Overall Reaction Order m + n = 2 so overall reaction is second order

Rate = k[NH4+][NO2-]

4. Option a) is correct

q = m c (T2-T1)

Since c is given in units of J/mol, you should convert the volume of water into moles:

25.00 mL X (1 g/mL) X (1 mol/18.0 g) = 1.39 mol H2O.

q = (1.39 mol) (75.38 J/mol) (95.0 - 10.0) = 8890 J or 8.89 kJ)

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.