Here are the answers to your questions:
8. A reaction that produces heat is an endothermic reaction.
B) False
(An endothermic reaction absorbs heat, while an exothermic reaction produces heat.)
9. Does Fiona's data support the law of conservation of matter, and why?
a) Yes, because the mass of the reactants is the same as the mass of the products in her data.
(Law of conservation of matter states that mass is not created or destroyed in a chemical reaction.)
10. What would happen if a scuba tank (a rigid, sealed gas cylinder) heats up?
a) The pressure exerted by the gas in the tank would increase.
(According to the ideal gas law, pressure increases with temperature in a closed system.)
11. Classify each change listed below as either a chemical or physical change in matter.
- Liquid water boiling and becoming steam - b. Physical Change
- Silver metal tarnishing and becoming silver sulfide - a. Chemical Change
- Paper burning - a. Chemical Change
- Bending copper wire - b. Physical Change
- Dissolving salt in water - b. Physical Change
- Iron rusting to become iron oxide - a. Chemical Change
12. Is this chemical reaction balanced: 1N2 + 3H2 - 2NH3?
True
(The number of atoms of each element is the same on both sides of the equation.)