Chemistry Exam Questions and Problems, Exams of Chemistry

Download Chemistry Exam Questions and Problems and more Exams Chemistry in PDF only on Docsity! Exam 2 Page 1 of 3 1. Which one of the following statements is FALSE? (a) In ordinary chemical reactions, atoms are neither created nor destroyed. (b) Coefficients of chemical formulas can be changed in order to balance a chemical equation. (c) The substances produced by a chemical reaction are called products. (d) The notation “(s)” after a substance’s formula indicates that the substance is a solid. (e) The notation “(aq)” after a substance’s formula indicates that the substance is a liquid. 2. Which one of the following statements is FALSE? (a) Addition of electrons to a substance is an oxidation. (b) Removal of hydrogen from a substance is an oxidation. (c) Removal of oxygen from a substance is a reduction. (d) Conversion of H+ to H2 is a reduction. (e) Conversion of sodium metal to Na+ is an oxidation. 3. Which one of the following statements is FALSE? (a) The net ionic equation for the reaction of a strong acid with a strong base is: H+ (aq) + OH- (aq) → H2O (l) (b) A base is a substance that produces OH- ions when dissolved in water. (c) An acid is a substance that produces H+ ions when dissolved in water. (d) Aqueous solutions of strong bases conduct electricity. (e) A precipitate forms when a strong acid is dissolved in water. 4. Which one of the following statements is TRUE? (a) The limiting reactant is defined as the reactant with the lowest molecular mass. (b) The limiting reactant is defined as the reactant with the smallest mole ratio in the balanced equation. (c) The limiting reactant is defined as the reactant with the lowest number of moles. (d) The theoretical yield = (moles of product/moles of limiting reactant)*100 (e) All of the above are false. 5. Which of the following experiments would allow you distinguish whether a white solid was NaCl or NaNO3? (a) Conductivity test (b) Reaction with phenolphtalein (c) Reaction with AgNO3 (d) Solubility in water (e) Reaction with iodine 6. Which of the following experiments would allow you distinguish whether a white solid was sucrose or K2SO4? (a) Conductivity test (b) Reaction with phenolphtalein (c) Reaction with NaOH (d) Solubility in water (e) Reaction with iodine 7. Which of the following is a correctly balanced equation? (a) 2 FeSO3 + 3 Al → 2 Fe + Al3(SO3)3 (b) 2 FeSO3 + 2 Al → 2 Fe + Al2(SO3)3 (c) 3 FeSO3 + 2 Al → 3 Fe + Al2(SO3)3 (d) 3 FeSO3 + 3 Al → 3 Fe + Al3(SO3)2 (e) 3 FeSO3 + 4 Al → 3 Fe + 2 Al2(SO3)2 Exam 2 Page 2 of 3 Atomic masses: H 1.008, C 12.01, N 14.01, O 16.00, Na 22.99, S 32.00 Avogadro’s number: 6.022 x 1023 8. Based on qualitative solubility rules, which of the following would not be soluble in H2O? (a) K2CO3 (b) BaCl2 (c) Na3PO4 (d) AgNO3 (e) CaSO4 9. How many moles of O2 are required for the complete combustion of 1 mole of C4H8O2 to give CO2 and H2O? (a) 4 moles (b) 5 moles (c) 6 moles (d) 8 moles (e) 10 moles 10. The formula mass of (NH4)2SO3 is: (a) 98 (b) 100 (c) 112 (d) 116 (e) 132 11. The number of moles of sodium in 276 g of Na2SO4 is: (a) 0.972 (b) 1.94 (c) 2.19 (d) 3.89 (e) 4.38 12. The mass of a sample containing 1.56 moles of C6H8O6 is: (a) 275 g (b) 176 g (c) 156 g (d) 113 g (e) 88.6 g 13. The number of molecules in a 5.00 g sample of CO2 is: (a) 2.28 x 1022 (b) 6.84 x 1022 (c) 2.05 x 1023 (d) 5.30 x 1024 (e) 6.84 x 1024 14. The mass of a single atom of nitrogen-14 is: (a) 4.66 x 10-23 g (b) 2.33 x 10-23 g (c) 1.99 x 10-23 g (d) 1.66 x 10-23 g (e) 1.66 x 10-24 g 15. The molecular formula for a compound with a formula mass of 256 g/mol and an empirical formula of C5H4S2 is: (a) C5H4S2 (b) C7H12S5 (c) C10H8S4 (d) C12H16S3 (e) C15H12S6