Question

1) 1) To convert a given number of moles into the number of atoms, one would multiply by which of the following factors? A) 1.66 x 10-24 atoms/1 mol B) 1 mol/6.022 x 1023 atoms C) molar mass D) 6.022 x 1023 atoms/1 mol E) 1 mol/1.66 x 10-24 atoms 2) Consider the following precipitation reaction. Which of the following correctly identifies the spectator ions in this reaction? Na2S(aq) + CuSO4(aq) → Na2SO4(aq) + CuS(s) A) Na+ and SO42- B) Na+, 52-, Cu2+, and S042- C) Na2+, 52-, Cu2+, and SO42- D) Cu2+ and 52- E) There are no spectator ions present. 3) Prozac, a drug prescribed to treat depression, has the formula C17H18F3NO. If a patient was administered 15.0 mg of Prozac, how many moles of Prozac did he receive? [Molar mass: Prozac, 309.36 g/mol) A) 2.92 x 1019 mol B) 4.85 x 10-5 mol C) 48.5 mol D) 20.6 mol E) 4640 mol 4) Consider the hypothetical reaction: 3A2 + 2B - C + 2D When 25 g of reactant A and 34 g of reactant B are combined, the theoretical yield of product C is 31 g. If the actual yield of product C is 19 g, what is the percent yield of C? A) 56% B) 85% C) 53% D) 76% E) 61%

Answer 1

We know that 1 mole of any substance contains Avogadro's number of atoms/molecules. To convert number of moles into atoms, we multiply the following factor Moles * 6.022 x 1023 atoms/mol Option D is the right answer. (2) Totalionic equation is 2 Na+ (aq) + 5-2 (aq) + Cu+2 (aq) + S04-(aq) -------> 2 Na+ (aq) + S04-2 (aq) + Cus (s) Net ionic equation is Cu+2 (aq) + 5-2 (aq) -------> Cus (s) The spectatorions are: Nat (aq), s04-(aq) Option A is the right answer.

(3) Mass = 15.0 mg = 0.015 g Molar mass = 309.36 g/mol Number of moles = mass/mol.wt. = 0.015 g/(309.36 g/mol) = 4.85 x 10-5 mol Option B is the right answer. (4) Percent Yield = Actual yield/theoretical yield * 100 = 19/31*100 = 61.29 % Option E is the right answer.