Review Exam 2 1.Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.23% abundance), X-29 (28.976 amu, 4.67% abundance), and X-30 (29.974 amu, 3.10% abundance). Calculate the atomic weight of X. A) 28.09 amu B) 48.63 amu C) 27.16 amu D) 28.97 amu E) 86.93 amu 2.What is the mass of 4 atom(s) of copper in grams? A) 254.2 g B) 2.37 10 21 g C) 9.57 10 24 g D) 6.022 10 23 g E) 4.22 10 22 g 3.Phosphoric acid can be prepared by reaction of sulfuric acid with phosphate rock according to the equation: Ca3(PO4)2 + 3H2SO4 3CaSO4 + 2H3PO4 How many oxygen atoms are there in 1.75 ng of Ca3(PO4)2? A) 3.40 10 12 B) 1.36 10 13 C) 8.43 10 15 D) 2.72 10 22 E) 2.72 10 13 4.How many atoms of hydrogen are present in 7.63 g of ammonia? A) 2.70 10 23 B) 1.52 10 24 C) 1.38 10 25 D) 8.09 10 23 E) 1.12 10 20 5.The molar mass of an insecticide, dibromoethane, is 187.9 g/mol. Its molecular formula is C2H4Br2. What percent by mass of bromine does dibromoethane contain? A) 42.52% B) 2.14% C) 85.05%
D) 12.78% E) 6.39% 6.You take an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen) with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of aspirin is between 170 and 190 g/mol. The molecular formula of aspirin is A) C6H8O5 B) C9H8O4 C) C8H10O5 D) C10H6O4 7.Vitamin C contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H by mass. The molar mass of vitamin C has been found to be about 180 g/mol. The molecular formula for vitamin C is: A) C2H3O2 B) C3H4O3 C) C4H6O4 D) C6H8O6 E) C14H18 8.Which of the following equations is not balanced? A) 4Al + 3O2 2Al2O3 B) C2H6 + O2 2CO2 + 3H2O C) 2KClO3 2KCl + O2 D) 4P4 + 5S8 4P4S10 E) P4 + 5O2 P4O10 9.What is the sum of the coefficients of the following equation when it is balanced using smallest whole numbers? A) 5 B) 6 C) 7 D) 8 E) 9 NaNH2 + NaNO3 NaN3 +NaOH + NH3 10.You heat 3.869 g of a mixture of Fe3O4 and FeO to form 4.141 g Fe2O3. The mass of oxygen reacted is A) 0.272 g B) 0.476 g
C) 1.242 g D) 1.000 g 11.Phosphoric acid can be prepared by reaction of sulfuric acid with phosphate rock according to the equation: Ca3(PO4)2 + 3H2SO4 3CaSO4 + 2H3PO4 Suppose the reaction is carried out starting with 129 g of Ca3(PO4)2 and 97.4 g of H2SO4. Which substance is the limiting reactant? A) Ca3(PO4)2 B) H2SO4 C) CaSO4 D) H3PO4 12.Consider the fermentation reaction of glucose: A 1.00-mole sample of C6H12O6 was placed in a vat with 100 g of yeast. If 32.3 grams of C2H5OH was obtained, what was the percent yield of C2H5OH? A) 35.1% B) 17.5% C) 100% D) 32.3% 13.Which of the following is a strong acid? A) HF B) KOH C) HClO4 D) HClO E) HBrO 14.Which of the following is not a strong base? A) Ca(OH)2 B) KOH C) NH3 D) LiOH E) Sr(OH)2 15.A 16.4-g sample of HF is dissolved in water to give 2.0 10 2 ml of solution. The concentration of the solution is:
A) 0.82 M B) 0.16 M C) 0.08 M D) 4.1 M E) 8.2 M 16.How many grams of NaCl are contained in 350. ml of a 0.287 M solution of sodium chloride? A) 16.8 g B) 5.87 g C) 11.74 g D) 100.5 g 17.What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H2SO4? A) 19 ml B) 0.33 ml C) 1.1 10 3 ml D) 2.9 ml E) 6.0 ml 18.Phosphoric acid, H3PO4, is a triprotic acid. What is the total number of moles of H + available for reaction in 2.50 L of 0.700 M H3PO4? A) 0.233 mole B) 2.10 mole C) 0.583 mole D) 3.00 moles E) 5.25 moles 19.The following reactions ZnBr2(aq) + 2AgNO3(aq) Zn(NO3)2(aq) + 2AgBr(s) KBr(aq) + AgNO3(aq) AgBr(s) + KNO3(aq) are examples of A) oxidation-reduction reactions B) acid-base reactions C) precipitation reactions D) A and C 20.Which of the following compounds is soluble in water? A) Ni(OH)2 B) K3PO4 C) BaSO4
D) CoCO3 E) PbCl2 21.Consider an aqueous solution of calcium nitrate added to an aqueous solution of sodium phosphate. What is the formula of the solid formed in the reaction? A) Ca(PO4)2 B) CaPO4 C) Ca3(PO4)2 D) Ca3(PO3)2 22.You mix 55 ml of 1.00 M silver nitrate with 25 ml of 0.84 M sodium chloride. What mass of silver chloride should you form? A) 3.0 g B) 6.0 g C) 3.3 g D) 6.6 23.When solutions of carbonic acid and copper(ii) hydroxide react, which of the following are spectator ions? A) hydrogen ion B) carbonate ion C) copper(ii) ion D) hydroxide ion 24.Sulfamic acid, HSO3NH2 (molar mass = 97.1 g/mol), is a strong monoprotic acid that can be used to standardize a strong base: A 0.165-g sample of HSO3NH2 required 19.4 ml of an aqueous solution of KOH for a complete reaction. What is the molarity of the KOH solution? A) 0.00170 M B) 8.76 M C) 0.0876 M D) 0.0330 M 25.In the reaction 2Cs(s) + Cl2(g) 2CsCl(s), Cl2 is A) the reducing agent B) the oxidizing agent
C) oxidized D) the electron donor E) two of these 26.Which of the following are oxidation-reduction reactions? I. PCl3 + Cl2 PCl5 II. Cu + 2AgNO3 Cu(NO3)2 + 2Ag III. CO2 + 2LiOH Li2CO3 + H2O IV. FeCl2 + 2NaOH Fe(OH)2 + 2NaCl A) III B) IV C) I and II D) I, II, and III E) I, II, III, and IV 27. Balance the following oxidation-reduction reaction using the oxidation number method: Fe 3+ + I Fe 2+ + I2 In the balanced equation, the coefficient of Fe 2+ is A) 1 B) 2 C) 3 D) 4 27.The MnO4 is often used to analyze for the Fe 2+ content of an aqueous solution via the reaction MnO4 (aq) + Fe 2+ (aq) + H + (aq) Fe 3+ (aq) + Mn 2+ (aq) + H2O(l) What is the ratio of Fe 2+ : MnO4 in the balanced equation? A) 1 : 1 B) 2 : 1 C) 3 : 1 D) 4 : 1 E) 5 : 1 28.Which of the following would represent the greatest pressure? A) 0.680 atm B) 517 mmhg C) 11.4 psi D) 62106 Pa E) 14.1 in Hg
29.Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container 1 is 1.30 L, and it contains 6.70 mol of the gas. The volume of container 2 is 2.33 L. How many moles of the gas are in container 2? A) 12.0 mol B) 20.3 mol C) 0.452 mol D) 3.74 mol 29.A gas sample is heated from -20.0 C to 57.0 C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.140 atm, what is the final pressure? A) 0.0477 atm B) 0.177 atm C) 0.411 atm D) 0.242 atm E) 0.0811 atm 30.A sample of gas is in a 50.0-mL container at a pressure of 645 torr and a temperature of 25 C. The entire sample is heated to a temperature of 35 C and transferred to a new container whose volume is 98.7 ml. The pressure of the gas in the second container is about: A) 457 torr B) 316 torr C) 1.32 10 3 torr D) 65 torr E) 338 torr 31.The mass of 1.12 liters of gas Y at STP is found to be 6.23 g. The molar mass of gas Y is A) 56.0 g/mol B) 89.0 g/mol C) 125 g/mol D) 140. g/mol E) 157 g/mol 32.It is found that 250. ml of a gas at STP has a mass of 0.700 g. What is the molar mass? A) 62.7 g/mol B) 2.80 g/mol C) 15.9 g/mol D) 11.2 g/mol E) 128 g/mol 33.At 1000 C and 10. torr, the density of a certain element in the gaseous state is element is:. The
A) F B) He C) Na D) Zn E) Hg 34.Oxygen gas, generated by the reaction is collected over water at 27 C in a 1.55-L vessel at a total pressure of 1.00 atm. (The vapor pressure of H2O at 27 C is 26.0 torr.) How many moles of KClO3 were consumed in the reaction? A) 0.0608 moles B) 0.0912 moles C) 0.0405 moles D) 0.0434 moles E) 1.50 moles 35.The partial pressures of CH4, N2, and O2 in a sample of gas were found to be 135 mmhg, 508 mmhg, and 571 mmhg, respectively. Calculate the mole fraction of nitrogen. A) 20.4 B) 0.470 C) 0.418 D) 0.751 E) 0.359