1. Which of the following statements about exothermic reactions is accurate?

A. The activation energy and the energy released from the reaction are the same.

B. The energy needed to activate an exothermic reaction is primarily thermal energy.

C. The energy given off is primarily in the form of thermal energy.

2. When a candle burns, it releases energy in the form of light and heat into the environment. This type of reaction is

A. endothermic B. exothermic C. catalytic

3. Which of the followingnottrue of a hydrate? A. A hydrate has water molecules chemically attached to its atoms.

B. A hydrate has water written into its chemical formula. C. A hydrate is an ionic compound dissolved in water.

4. Forces inside the nucleus of an atom can cause changes that release particles and energy.

A. True B. False

5. When protons are too far apart to be attracted by the strong force, they are still repelled by which force?

A. weak force B. electromagnetic force C. atomic repulsion

6. The following chemical reaction shows the decomposition of water to form hydrogen gas and oxygen gas: 2H2O(l) 2H2(g) + O2(g)

If 10.0 grams of water reacted and 8.89 grams of O2formed, how many grams of H2would also be formed?

A. 0.11 grams B. 1. 11 grams C. 0.889 grams

7. In a single-displacement reaction A. one or more substances combine to form another substance. B. an element replaces another element in a compound to produce a new

molecule. C. one substance breaks down into two or more substances

8. An oxidation reaction is shown in a chemical equation by which of the following?

A. Energy must be released as a substance decomposes. B. It must show the formation of a precipitate. C. It most often shows a substance combining with oxygen.

9. What is the chemical formula of the covalent compound sulfur dioxide? A. SO2

B. SO C. S2O2

10. A change of one element to another through nuclear decay is called A. nuclear radiation.

B. transmutation. C. nuclear fusion.

11. The covalent compound named triphosphorous dioxide is represented by which of the following chemical formulas?

A. P3O2B. P2O3C. P7O2

12. How do hydrogen and oxygen combine to form a stable water molecule? A. they share electrons

B. hydrogen loses an electron to oxygen C. oxygen loses an electron to hydrogen

13. An ionic bond is A. an atom that has lost a neutron.

B. a compound with a neutral charge. C. formed when the atoms lose or gain quarks.

14. Which of the following radiation detection methods uses a superheated liquid? A. cloud chamber

B. bubble chamber C. electroscope

15. A radioactive material has a half-life of 10 years. If you start with 200 g of the material how much of the original amount will remain after 30 years?

A. 100 g B. 60 g C. 25 g

16. When magnesium combines with oxygen to form an ionic bond, what is the formula of the compound? Recall that magnesium metal atoms have two electrons in their outer level and oxygen atoms have six outer-level electrons.

A. Mg6O2B. Mg2O6C. MgO

17. Choose the correct coefficients to balance the following equation. ___ H2SO4(l) + ___ Al(OH)3(l) ___H2O (l) + ___ Al2(SO4)3(aq)

A. 2, 3, 3, 1 B. 3, 2, 6, 2 C. 3, 2, 6, 1

18. When the radioactive material polonium decays, it undergoes transmutation and turns into lead. It also releases alpha particles of radiation.

A. True B. False

19. Compounds formed when elements combine often have properties unlike those of its individual elements.

A. True B. False

20. When more energy is required to create the reaction than is released by the reaction, we call this a(n)

A. endothermic energy. B. catalytic reaction. C. endergonic reaction.

21. Nuclear fission and nuclear fusion can best be described by which of the following?

A. Fission takes place in the Sun, while fusion is used to run most nuclear power reactors.

B. Fission involves bringing smaller nuclei together, while fusion involves splitting heavier nuclei into smaller pieces.

C. Fission and fusion are both capable of releasing tremendous amounts of energy that can be determined with Einstein's equation:E = mc2.

22. In a nonpolar bond

A. electrons are shared unequally, resulting in a slightly positive end and a slightly negative end.

B. electrons are shared equally by both atoms. C. the number of positive charges equals the number of negative charges.

23. Which of the following best describes how a Geiger counter works?

A. When radiation enters this gas-filled tube, it knocks electrons off the gas particles, resulting in an electric current that is transmitted via a charged wire to a counting mechanism.

B. Radioactive sources are placed close to tumors. This radiation will damage the tumor while minimizing damage to the surrounding tissue.

C. Neutrons emitted from a split nucleus cause other nuclei to split and emit additional neutrons, and a chain reaction occurs.

24. Which of the following reactions describes the process by which hydrogen and oxygen form water?

A. single-displacement reaction B. precipitate reaction C. synthesis reaction

25. How many atoms does the formula of cadmium nitrate Cd(NO3)2contain?

A. 6 B. 8 C.9

26. When nonmetals form ions, they always lose electrons and metals always gain electrons.

A. True B. False

27. The rate of reaction is only affected by a chemical's temperature and concentration, the amount of surface area exposed, and the level of agitation do not affect it.

A. True B. False

28. Which of the following reasons best explain why noble gases rarely combine with other elements to form compounds.

A. They are gases. B. Their atoms are much too large. C. Their outer energy levels are full.

29. The weak force is the force that holds atoms together in a compound. A. True B. False

30. A neutral ionic compound contains ions with different charges that combine in specific amounts so that the positive charges are exactly equal to the negative charges.

A. True B. False

31. When hydrogen peroxide changes to water and oxygen in the reaction 2H2O2(aq) 2H2O(l) + O2(g), what type of reaction does this represent?

A. decomposition B. synthesis C. double-displacement

32. Why are nuclear tracers useful in medicine and scientific research?

A. Tracers absorb background radiation.

B. Tracers form new detectable chemical bonds with other atoms to help

scientists detect them more easily.

C. Tracers emit detectable radiation and behave chemically like their non-

radioactive isotopes.

33. What is the ratio of carbon atoms to oxygen atoms in the chemical formula C12H22O11(cane sugar)?

A. 2 to 1 B. 12 to 11 C. 6 to 11

34. Which of these is a reason a catalyst is added to a chemical reaction? A. to stabilize a substance

B. to speed up a reaction C. to prevent a compound from forming

35. The attraction that forms between atoms when they share electrons is known as a covalent bond. The neutral particle that forms as a result of this electron sharing is called a molecule.

A. True B. False

36. How many electrons are found in the outer level of an atom of calcium? (Calcium is found in group 2 on your periodic table.)

A. 1 B. 2 C.6

37. The following balanced equation shows one of the reactions between stomach acid (HCl) and a common commercial antacid: 2HCl(aq) + CaCO3(s)

CaCl2(aq) + CO2(g) + H2O(l).

What number results from adding the value of all the coefficients in this equation?

A. 2 B. 3 C.6

38. The radioactive isotope I-131 is used medically in thyroid investigations. This isotope has a half-life of approximately 8 days. Starting with 14 grams of I- 131, how much would remain after 24 days?

A. 3. 5 grams B. 1. 75 grams C. 7 grams

39. An inhibitor will speed up a chemical reaction by increasing the activation energy needed to start the reaction.

A. True B. False

40. Jessica wants to test the law of conservation of mass by performing an experiment with charcoal. Which of the following instruments would she use to weigh her materials?

A. ammeter B. volumetric flask C. triple-beam balance

41. A polar covalent bond can best be described by which of the following statements?

The bond will have one side that is slightly positive and another side that is slightly negative.

CCl4is an example of a molecule with polar covalent bonds.

The attraction for electrons between two atoms with a polar covalent bond is equal.

42. Using the partial activity list given, determine which element would be able to react with zinc ions from a solution.

A. aluminum B. copper C. iron

43. In which method of radiation detection are the vapor trails of alpha and beta particles visible as they travel?

A. positron emission tomography B. bubble chamber C. cloud chamber

44. Which of the following is a stable element, with eight electrons in its outer energy level?

A. hydrogen B. sodium C. argon

45. Which of these isnotevidence of a chemical reaction? A. A piece of zinc placed in acid raises the temperature of the acid.

B. An ice cube melts into liquid water. C. An antacid table produces bubbles of gas when placed in water.

46. How do you indicate that a substance in an equation is a gas?

A. (aq) B. (s) C. (g)

47. Which of the following explains why ionic compounds generally have high melting points?

A. They share each other's electrons, strong forces develop that require large amounts of heat to break apart.

B. In an ionic solid, oppositely charged ions are strongly attracted to each other throughout the crystal.

C. They are frequently in a gas form, and this is particularly difficult to melt.

48. What is always true in covalent bonding?

A. The number of positive charges must equal the number of negative charges.

B. The electrons are shared between the atoms, either equally or unequally. C. Only one pair of electrons is shared between the atoms.

49. In synthesis reactions, substances break down into two or more substances. A. True

B. False

50. Which of these would penetrate a car door made of aluminum? A. alpha particles

B. beta particles C. gamma rays