What do the group numbers mean on the periodic table?

Explain how you know that gasoline burning in a car engine is a chemical change.?

Describe the energy changes that place when the spring of a toy car is wound up and then released

In an inelastic collision, which of the following statements is always true? [A] Kinetic energy is conserved in the collision. [B] Momentum is conserved in the collision. [C] After the collision, the objects always merge into one.

A motor does 8000j of work in 20 seconds. What is the power of the motor

Which happens during the day at the beach? A. The water is warmer than the land, and air sinks over the water B. The water is cooler than the land, and air sinks over the water C. The water is warmer than the land, and air rises over the water D.

The acceleration of gravity means that for each second that passes, falling objects move 9.8 meters. A. True B. False

Explain, using numbered steps, how you could find the volume of a small, irregularly shaped rock.

Which of the following is not a receptor pair according to the opponent process theory? A. red versus green B. yellow versus blue C. black versus white D. yellow versus red

A scientist adds different amounts of salt to 5 bottles of water. He then measures how long it takes for the water to boil. what is the dependent variable in this experiment?

Bacteria which do not live in extreme conditions are found in this kingdom: