1. Which of the following is not an example of a homogenous mixture? a. b. c. d. e. Homogenized milk A mixture of N2, H2 and NH3 A solution of gold in mercury A solution of potassium chloride in water Air 2. Which of the following pairs are allotropes: (a) red phosphorus and white phosphorus (b) dioxygen and ozone (c) diamond and graphite (d) deuterium and tritium (e) orthorhombic and monoclinic sulfur (f) liquid N2 and gaseous N2 a. b. c. d. e. a, b, c, d, e and f a and e only a, b, c, and e only a, c, and e only a, b, c, d, and e only 3. A 25 g sample of an unknown compound is reacted with water. The reaction goes to completion and the products are measured to have a total mass of 136 g. How much water reacted? a. b. c. d. e. 111 g 161 g 5g 25 g it cannot be determined from the information given 2 4. Sulfur and nitrogen form a number of binary compounds. Using the data below, and given that the formula of compound A is S4N4, what is a possible formula for compound B? A B Mass of N that combines with 1 g of S 0.4375 g 0.2188 g a. b. c. d. e. SN4 S5 N6 S4 N2 S2 N2 SN2 5. Which of the following postulates of Dalton’s theory of matter was later shown to be incorrect? (i) Elements consist of tiny indivisible particles called atoms. (ii) All atoms of a given element are identical in mass and other properties. (iii) Different elements have different kinds of atoms. (iv) Compounds are formed when atoms of unlike elements combine in small wholenumber ratios. (v) Atoms retain their identities in a chemical process and a chemical reaction merely changes the way in which the atoms are bonded together. a. b. c. d. e. (i) only (ii) only (i), (ii) and (iii) (i) and (ii) (ii), (iii) and (iv) 6. Thomson was able to determine the charge to mass ratio of the electron by which of the following? a. b. c. d. e. Varying the frequency of light incident on a metal plate Measuring the charge required to suspend a charged oil drop Observing the deflection of a cathode ray in magnetic and electric fields Observing the diffraction pattern of an electron beam Observing the visible light spectrum of an excited hydrogen atom 3 7. Which of the following statements about subatomic particles and atoms is incorrect? a. The electron is negatively charged, the proton has a positive charge that is equal in magnitude to that of the electron, and the neutron has zero charge. The mass of a proton is more than 1000 times greater than the mass of an electron. The volume occupied by the nucleus in an atom is much smaller than the volume occupied by the electrons. Evidence for the nucleus was first obtained experimentally by firing electrons at a sheet of gold foil. The nuclei of different elements contain different numbers of protons. b. c. d. e. 8. An isotope of an element has a mass number of 14 amu. What is the identity of the element if the isotope contains 8 neutrons? a. b. c. d. e. B Si C Li N 9. Ba2+ has a. b. c. d. e. 0 valence electrons and 54 core electrons 0 valence electrons and 56 core electrons 2 valence electrons and 52 core electrons 2 valence electrons and 54 core electrons 2 valence electrons and 56 core electrons 4 10. Select the list of elements that would respectively complete the following statements. ___ is an element that reacts violently with water at room temperature ___ is a metal that has 28 electrons as a 2+ ion. ___ is a red liquid at room temperature and atmospheric pressure ___ is ductile a. b. c. d. e. Li, Zn, Br, S Na, Ni, Br, Cu Na, Ni, Br, S Na, Zn, Br, Cu K, Zn, Se, S 11. Which of the following statements is FALSE? a. b. c. d. e. Sodium and potassium are alkali metals Oxygen is a halogen Nitrogen and phosphorus belong to the same Periodic Group Helium and argon are not very reactive Iron is a transition metal 12. Bromine has two naturally occurring isotopes: 79Br (atomic mass of 78.92, 50.69% abundant) and 81Br (atomic mass of 80.92, 49.31% abundant). How many signals should be observed if ions of naturally occurring Br2 are detected in a mass spectrometer? a. b. c. d. e. 0 1 2 3 4 13. 0.75 g of a compound contains 1.734 × 1022 molecules. What could be its molecular formula? a. b. c. d. e. CH C2H2 C2 N2 Te2 5 14. Which of the following samples contains the greatest number of atoms? a. b. c. d. e. 65 g CH4 700 g SOCl2 750 g CaBr2 280 g CO 800 g Kr 15 Consider the formation of ammonia from the reaction of N2 with H2. How much N2 would be required to react completely with 1.50 mol of H2? a. b. c. d. e. 14.0 g 28.0 g 42.0 g 56.0 g 126 g 16. Aluminum and bromine react according to the following equation: 2Al + 3Br2 → 2AlBr3 What mass of AlBr3 is formed if 21.4 g of Al and 14.6 g of Br2 are allowed to react, assuming 100% yield? a. b. c. d. e. 212 g 16.2 g 24.4 g 36.5 g 36.0 g 17. How much water is produced when 5.0 g of glucose (C6H12O6) burns in 26 g of O2? a. b. c. d. e. 14.64 g 30.00 g 3.00 g 0.50 g 0.17 g 6 18. The empirical formula of a group of compounds is CHCl. Lindane, a powerful insecticide, is a member of this group. The molar mass of lindane is 290.8 g mol-1. How many atoms of carbon does a molecule of lindane contain? a. b. c. d. e. 2 3 4 6 1 19. Glutathione consists of carbon, hydrogen, oxygen, nitrogen, and sulfur. When 0.2528 g of glutathione is burned in an excess of oxygen, 0.3620 g of carbon dioxide and 0.1261 g of water are formed. Glutathione is 13.68% nitrogen by mass and 10.44% sulfur by mass. Its molar mass is between 300 and 310 g mol–1. What is the molecular formula for glutathione? a. b. c. d. e. C10H18N3O4S2 C11H18N3O3S2 C10H18N4O3S2 C10H17N3O6S C10H30N4O4S 20. What is the percentage by mass of nitrogen in magnesium nitrate? a. b. c. d. e. 19.92 % 16.22 % 12.66 % 18.89 % 24.08 % 7 21. Carbon monoxide (CO) will react with oxygen (O2) to form carbon dioxide (CO2). How many liters of carbon dioxide can be formed from 1.5 L of carbon monoxide (with excess oxygen) if all the gas volumes are measured the same temperature and pressure? a. b. c. d. e. 0.15 L 0.5 L 0.75 L 1.5 L 3.0 L 22. Which of the following compounds has the most covalent character? a. b. c. d. e. KI KBr KCl HCl HI 23. Which of the following has the smallest radius? a. b. c. d. e. As3– Se2– Br– Rb+ Sr2+ 24. Which of the following statements about lattice energies is false? a. b. c. d. The magnitude of the lattice energy is greatest for small and highly charged ions. The magnitude of the lattice energy of Al2O3 is larger than that for MgO. The magnitude of the lattice energy of K2O is larger than that for MgO. The lattice energy is the energy change associated with the formation of an ionic solid from gaseous ions. The energy change associated with the formation of the gaseous ions from an ionic solid is of equal magnitude but opposite sign to that for the formation of an ionic solid from gaseous ions. e. 8 25. Given the following bond energies C–H (413 kJ mol–1), Cl–Cl (239 kJ mol–1), F–F (154 kJ mol–1), C–F (485 kJ mol–1), C–Cl (339 kJ mol–1), H–F (565 kJ mol–1), H–Cl (427 kJ mol–1) Estimate the energy change, ΔE, for the reaction of 1 mole of CH4 with Cl2 and F2 according to the following equation CH4 + 2Cl2 + 2F2 → CF2Cl2 + 2HF + 2HCl a. b. c. d. e. –1194 kJ +1194 kJ –202 kJ +202 kJ –1010 kJ