Understanding Chemical Reactions: Balancing Equations and Energy Calculations

1. Spring Benchmark #2 Review

2. Identify the coefficients to properly balance the following equation: Na + AuCl3 NaCl + Au • 3,3,1,1 • 3,1,3,1 • 1,3,1,3 • 1,1,3,3

3. Identify the potential energy of the products. • A. 50 kJ • B. 200 kJ • C. 100 kJ • D. 150 kJ

4. 2H2 + O2 2H2O If 3.25 moles of hydrogen react with oxygen, how many grams of water can be produced? A. 100 g B. 117 g C. 29.25 g D. 58.5 g

5. Calculate the enthalpy change for the reaction. • A. 200 kJ • B. 50 kJ • C. 100 kJ • D. 250 kJ

6. What effect does a catalyst have on a reaction? • A. lowers the activation energy required • B. decreases enthalpy • C. increases enthalpy • D. no change

7. Write the reaction for the combustion of propane (C3H8).

8. 10 In any chemical reaction, the mass of the products is ___ the mass of the reactants. • Greater than • Less than • Equal to • None of the above

9. Na + AuCl3 NaCl + Au • Identify the type of reaction shown above. A. Single replacement B. synthesis C. Double replacement D. decomposition

10. Identify the melting point of the substance at 73 atm. • A. 216.6 K • B. 304.25 K • C.197.5 K • D. 0 K

11. 10 Balance the following equation:___K + ___O2 __ K2O • 4,1,2 • 4,2,1 • 1,1,1 • 2,4,1

12. 10 Which gas composes the greater percentage of the atmosphere? • Helium • Hydrogen • Nitrogen • Oxygen

13. 10 The instrument used to measure temperature is the ___. • Balance • Thermometer • Barometer • Graduated cylinder

14. Identify the phase chage when the temperature changes from 197.5 K to 250 K if the pressure remains constant at 73 atm. • A. freezing • B. sublimation • C. Deposition • D. melting

15. 10 In the metric system, temperature is measured on the ___ scale. • Celsius • Fahrenheit • Cesium • Francium

16. Calculate the energy required to melt 45 g of ice. • Heat of fusion=334 • Heat of vaporization=2260 • A.101,700J • B.15030J • C.0.134J • D.6.65J

17. Regular Chem only • Identify the type of particle that can be blocked by concrete or lead • A. Alpha • B. Beta • C. Gamma

18. 10 A child notices her balloon is smaller inside her air conditioned house than outside in the sun. This is an example of ___ law. • Avogadro’s • Boyle’s • Charles’ • Graham’s

19. What is the normal sublimation point of the substance? A. 216.6 K B. 304.25 K C. 197.5 K D. 0 K

20. 10 According to Boyle’s law, the pressure of a gas will ___ when the volume decreases. • Increase • Decrease • Remain the same

21. 10 Air consists of ___. • One kind of gas • A mixture of several gases • A single compound • Only non-reactive gases

22. 10 All of the following are pressure units except • mm Hg • atm • kPa • K

23. 10 As the temperature increases, the motion of particles ___. • Increases • Decreases • Remains the same

24. 10 No molecular motion occurs ___. • At night • In the atmosphere • At absolute zero • At the freezing point

25. 10 Of the three states of matter, ___ is the highest energy. • Solid • Liquid • Gas

26. 10 Particles of matter in the ___ state are moving very quickly and do not form a definite pattern. • Solid • Gaseous • Atomic • Nuclear

27. 10 As the temperature in a tank of propane increases, the pressure ___. • Increases • Decreases • Remains constant • Decreases, then increases

28. 10 Because of its high heat capacity, the temperature of ___ changes slower than most substances. • Alcohol • Oil • Gasoline • Water

29. 10 STP is ___. • 0oC and 1 atm pressure • 0oK and 1 atm pressure • 25oC and 1 atm pressure • 273oC and 700 mm Hg

30. 10 The process by which a liquid is converted to a gas without boiling is • Precipitation • Evaporation • Condensation • Vaporization

31. 10 The __ the altitude, the lower the pressure. • Lower • Higher

32. 10 What volume will one mole of a gas occupy under STP? • 1 L • 22.4 L • 273 L • 293 L

33. 10 What idea can be used to explain both Boyle’s and Charles’ laws? • Atomic theory • Kinetic molecular theory • Law of conservation of matter • Law of conservation of energy

34. 10 Which law explains why bread rises when baked? • Avogadro’s • Boyle’s • Charles’ • Graham’s

35. 10 Which law explains why soft drinks “pop” when opened? • Avogadro’s • Boyle’s • Charles’ • Kelvin’s

36. 10 Any time physical or chemical changes occur, you also ___. • Have energy changes • Gain mass • Lose energy • Have color changes

37. 10 In a(n) __ reaction, energy is given off. • Endothermic • Exothermic • Isothermic

38. 10 The energy in compounds is held in the • Oxygen atoms • Hydrogen atoms • Chemical bonds between atoms • Water molecules

39. 10 The minimum energy needed to start a reactions is called the • Energy of formation • Lattice energy • Bond energy • Activation energy

40. 10 When chemicals are mixed in a test tube and the test tube becomes hotter, a __ reaction has occurred. • Exogenic • Exothermic • Endogenic • Endothermic

41. 10 A compound that speeds up a reaction without being consumed itself is a(n) • Additive • Catalyst • Raw material • Resource

42. 10 If you increase the temperature, the rate of reaction will • Increase • Decrease • Remain the same

43. 10 In chemical equations, “aq” means • In a water solution • A crystal • A pure compound • A gas

44. 10 In a combustion reaction, the products are • Hydrogen • Carbon dioxide and water • Oxygen and water • oxygen

45. 10 The chemicals on the left side of the arrow are called • Molecules • Reactants • Products • Sugar