Question

1. at what temperature does water boil at sea level (standard atmospheric pressure)?

a. 0°c
b. 100°c
c. 273 k
d. 212°f

1. which phase change involves the absorption of heat energy from the surroundings?

a. melting
b. freezing
c. sublimation
d. boiling

1. a teacher is investigating the impact of class size on student performance. in this study, the independent variable is:

a. the grade level of the students
b. the student performance
c. the size of the class
d. the subject being taught

1. a chef is experimenting with different cooking times to determine how it affects the tenderness of a steak. the dependent variable in this experiment is:

a. the cooking time
b. the type of steak
c. the tenderness of the steak
d. the cooking temperature

1. a biologist is investigating the growth of a particular species of plant under controlled conditions. the temperature in the growth chamber is maintained at a constant value. what is the constant in this experiment?

a. the type of plant species
b. the growth rate of the plant
c. the temperature in the growth chamber
d. the amount of water provided to the plant

Explanation:

1. At standard atmospheric pressure, water boils at 100°C (212°F or 373 K). 273 K is the freezing - point of water in Kelvin. So the correct answers are b. 100°C and d. 212°F.
2. Melting (solid to liquid), sublimation (solid to gas), and boiling (liquid to gas) are endothermic processes that absorb heat from the surroundings. Freezing (liquid to solid) is an exothermic process. So the answers are a. Melting, c. Sublimation, d. Boiling.
3. In an experiment investigating the impact of class size on student performance, the independent variable is the factor that is being changed or manipulated, which is the size of the class. So the answer is c. The size of the class.
4. In an experiment where a chef is determining how cooking time affects the tenderness of a steak, the dependent variable is the variable that is being measured or observed, which is the tenderness of the steak. So the answer is c. The tenderness of the steak.
5. A constant in an experiment is a variable that is kept the same throughout. Since the temperature in the growth chamber is maintained at a constant value, it is the constant. So the answer is c. The temperature in the growth chamber.

Answer:

1. b. 100°C, d. 212°F
2. a. Melting, c. Sublimation, d. Boiling
3. c. The size of the class
4. c. The tenderness of the steak
5. c. The temperature in the growth chamber