An experiment is designed to test what color of light will activate a photoelectric cell the best. the photocell is set in a circuit that "clicks" in response to current. the faster the current, the more clicks per minute. in this experiment, the number of clicks in one minute is recorded for each color of light shining on the photocell. to change the color of light, a different color of cellophane is placed over the same flashlight and the flashlight is then located a specific distance from the photocell. in the above experiment, which factor is the independent variable? the number of clicks the color of the light the original source of the light the photocell

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas. in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

14. many depressants reduce small muscle control, making it harder for a. you to steer b. your mind to consider complex problems c. the eye to scan, focus, or stay still d. the kidneys to filter alcohol out of the bloodstream

Liv sheldon given the balanced equation for an organic reaction: c2h2 + 2cl2 → c2h2cl4 this reaction is best classified as *