Grade 12 Chemistry practice

What is on the worksheet

1. The given standard reduction potentials are 0.47 V for the cathode and -0.77 V for the anode. Find E°cell. Round to 3 decimal places if needed. Answer in V.

2. A hydrocarbon molecule contains 8 carbon atoms. In a complete-combustion model, all its carbon forms CO₂. How many moles of CO₂ come from 3.8 mol hydrocarbon? Round to 3 decimal places if needed. Answer in mol.

3. At 25 °C, use the dilute model pH + pOH = 14. A solution has pH 5.1. Find pOH. Round to 3 decimal places if needed.

4. A 168 g sample is 71% desired substance by mass. Find the desired substance mass. Round to 3 decimal places if needed. Answer in g.

5. For A ⇌ B, use Kc = [B]/[A]. Equilibrium concentrations are [A] = 2.4 and [B] = 2.8 mol/L. Find Kc. Round to 3 decimal places if needed.

6. The theoretical dry pure product mass is 68 g; the actual dry pure product mass is 38 g. Find percentage yield. Round to 3 decimal places if needed. Answer in %.

7. A 82 mL aliquot at 1.5 mol/L is diluted to 164 mL total without reaction or loss. Find the final concentration. Round to 3 decimal places if needed. Answer in mol/L.

8. Measured from the same origin, a spot travels 5 mm and the solvent front 37 mm. Find Rf. Round to 3 decimal places if needed.

9. A reactant concentration decreases from 0.68 to 0.52 mol/L in 59 s. Find its positive average disappearance rate. Round to 3 decimal places if needed. Answer in mol/(L·s).

10. A simple unbranched, noncyclic peptide contains 152 amino-acid residues. How many peptide links connect adjacent residues? Round to 3 decimal places if needed.

11. An aqueous solution has concentration 0.2 mol/L. A model aliquot has volume 289 mL. Find the solute amount. Round to 3 decimal places if needed. Answer in mol.

12. For the abstract reaction A + 2B → C, 32 mol A and 10 mol B are available. Assume complete consumption of the limiting reactant. Find the maximum amount of C. Round to 3 decimal places if needed. Answer in mol.

13. An ideal gas has initial pressure 200 kPa and volume 4.8 L. At fixed amount and temperature its volume becomes 5.5 L. Find the new pressure. Round to 3 decimal places if needed. Answer in kPa.

14. An ideal gas has initial pressure 113 kPa and volume 5.1 L. At fixed amount and temperature its volume becomes 9 L. Find the new pressure. Round to 3 decimal places if needed. Answer in kPa.

15. A hydrocarbon molecule contains 6 carbon atoms. In a complete-combustion model, all its carbon forms CO₂. How many moles of CO₂ come from 7 mol hydrocarbon? Round to 3 decimal places if needed. Answer in mol.

16. The given standard reduction potentials are 0.14 V for the cathode and -0.4 V for the anode. Find E°cell. Round to 3 decimal places if needed. Answer in V.

17. The theoretical dry pure product mass is 90 g; the actual dry pure product mass is 9 g. Find percentage yield. Round to 3 decimal places if needed. Answer in %.

18. The theoretical dry pure product mass is 106 g; the actual dry pure product mass is 34 g. Find percentage yield. Round to 3 decimal places if needed. Answer in %.

19. For one reaction as written, a bond model requires 609 kJ/mol to break bonds and releases 771 kJ/mol on forming bonds. Estimate ΔH. Round to 3 decimal places if needed. Answer in kJ/mol.

20. A model sample has mass 169 g and stated molar mass 33 g/mol. Find its amount. Round to 3 decimal places if needed. Answer in mol.