Chapter 9

1. Why did the defense maintain that Kenny Richey probably did not start the fire of which he was accused? He had no matches on him to start a fire. He hadn't taken the gasoline or paint thinner. He had no gasoline or paint thinner residue on him, and had a broken hand, making it hard to handle and spread such liquids. He had no past arrests for arson.

2. What ingredients are needed for a fire? a fuel source oxygen gas heat all of the above

3. What is heat? a mass form transferred from object to object upon contact an energy form transferred from object to object upon contact a mass–energy transfer when hot and cold objects come into contact an energy form transferred from hot to cold objects when they come in contact with each other

4. When two or more objects touch and reach the same temperature, this condition is called static equilibrium thermal equilibrium dynamic equilibrium isotonic equilibrium

5. What is the SI unit of heat energy? the joule the calorie the coulomb the oC

6. What is another term for a smoke explosion? a limiting thrust a vapor blow a back draft a fire triangle

7. Why are some wood-based smokes white and others black? It depends on the completeness of the burning. It depends upon the water content of the wood being burned. It depends on the color of the wood being burned. It depends on the size of the wood being burned.

8. The complete combustion of wood has carbon dioxide as one of its products. True False

9. Balancing a combustion equation should be done in what elemental order? C-H-O H-O-C O-H-C C-O-H

10. Which is the balanced equation for the complete combustion of ethanol (C2H5OH) in oxygen gas? C2H5OH + 7 O2 2 CO2 + 3 H2O 2 C2H5OH + 6 O2 4 CO2 + 6 H2O 2 C2H5OH + 7/2 O2 4 CO2 + 6 H2O C2H5OH + 7 O2 4 CO2 + 6 H2O

11. Which is the balanced equation for the complete combustion of methanol (CH3OH) in oxygen gas? 2 CH3OH + O2 2 CO2 + 4 H2O 2 CH3OH + 3 O2 2 CO2 + 4 H2O CH3OH + 3 O2 2 CO2 + 2 H2O CH3OH + 3 O2 CO2 + 4 H2O

12. The complete combustion of methane gas (CH4) in oxygen gas is what? CH4 + 2 O2 CO2 + 2 H2O 2 CH4 + 2 O2 2 CO2 + 2 H2O CH4 + 2 O2 2 CO2 + 2 H2O 2 CH4 + 2 O2 CO2 + 2 H2O

13. What is the oxidation number of chlorine in MgCl2? –2 –1 +1

14. In water, what is the oxidation state of oxygen? –2 +1 +2

15. To what does the term oxidation refer? the gain of electrons the movement of electrons the loss of electrons the reduction of electrons

16. Why is heat needed to initiate combustion? Energy is needed to start the fuel–oxygen reaction. Liquids and solids need to be converted to vapors. neither of the above both of the above

17. What do all exothermic reactions produce? heat light smoke fumes

In an exothermic reaction energy diagram, what is the relationship between the reactants' and the products' energies? The products are higher than the reactants. The reactants are higher than the products. Both reactants and products are the same energy. The reactants are always higher than the activation energy.

19. Endothermic processes always give off heat at the completion of the reaction. True False

20. What physical change occurs at the melting point of a material? liquid becomes gas solid becomes liquid liquid becomes solid solid becomes gas

21. How is specific heat defined? the amount of heat needed to raise 1 mole of material 1oF the amount of heat needed to raise 1 g of material 1oF the amount of heat needed to raise 1 mole of material 1oC the amount of heat needed to raise 1 g of material 1oC

22. In the temperature vs. heat diagram below what does a plateau represent? an equilibrium adjustment the loss of heat the addition of heat a phase change

23. How much higher is the specific heat of water than of the metals listed in Table 1? (p. 281) at least four times at least eight times at least ten times It is not higher at all.

24. The amount of energy required to convert a liquid to a gas is known as what? the heat of conversion the heat of vaporization the heat of gasification the heat of nebulization

25. What is the heat of fusion? the heat needed to melt a solid completely. the heat required to join two metals. the heat needed to separate two metals. the heat required to melt a fuse.

26. How much heat is evolved when a 35 26. How much heat is evolved when a 35.0 g sample of copper increases from 25.0oC to 35.5oC? 472.0 J 139.7 J 262.5 J 13.3 J

27. When a 213.0 g sample of aluminum is raised in temperature from 22.0oC to 95.0oC, what amount of heat is produced?(p.281) 13,994 J 18,211 J 4,217 J 15,549 J

28. When a 500. 0 g sample of silica glass changes temperature from 23 28. When a 500.0 g sample of silica glass changes temperature from 23.0oC to 50.0oC, what amount of heat is involved?(p.281) 18,750 J 10,125 J 8,625 J 25,000 J

29. What does the following graph represent? Exothermic reaction Endothermic reaction Erythrothermic reaction A lame roller coaster ride

30. What does the following graph represent? Exothermic reaction Endothermic reaction Erythrothermic reaction A lame roller coaster ride

31.How does a flashover spread? across the ceiling of a room where a fire exists through the ventilation system of a house across the floor of a room where a fire exists through other combustible material in a room where a fire exists

32. What physical change occurs at the melting point of a material? liquid becomes gas solid becomes liquid liquid becomes solid solid becomes gas

endothermic reaction exothermic reaction exergonic reaction In chemical reactions between substances, energy is either released or absorbed. 33. Read the statement given above. What type of chemical reaction occurs when the product of a reaction is colder than the reactants? endothermic reaction exothermic reaction exergonic reaction catalyzed reaction

endothermic reaction exothermic reaction exergonic reaction In chemical reactions between substances, energy is either released or absorbed. 34. Study the statement given above. What type of chemical reaction occurs when energy must be provided for the reaction to take place? endothermic reaction exothermic reaction exergonic reaction catalyzed reaction

35.The graph below illustrates what type of reaction? endothermic exothermic exergonic unable to determine from the information given

36. Water cools from 4°C to –4°C 36.Water cools from 4°C to –4°C. During this time, what happens to the motion of the molecules? The motion of the molecules stops.  The motion of the molecules increases.  The motion of the molecules decreases.  The motion of the molecules remains the same.

Potential energy diagram 37. -120 kJ -40 kJ + 160 kJ + 40 kJ

38. The specific heat of aluminum is about 0. 90 J/g oC 38. The specific heat of aluminum is about 0.90 J/g oC. The specific heat of water is about 4.184 J/g o C. If you have the same number of grams of aluminum and water, compare the amount of heat it would take to get the same temperature change. The aluminum will need more heat added They both will require the same amount of heat The water will need more heat added Not enough information is given

50oC and 3 min 50oC and 5 min 110oC and 4 min 110oC and 14 min 39. Starting as a solid, then liquid, and then gas, a sample of a substance is heated at a constant rate. The graph below shows the changes in temperature of this sample. What is the melting point of the sample and the total time required to completely melt the sample after it has reached its melting point? 50oC and 3 min 50oC and 5 min 110oC and 4 min 110oC and 14 min