How do you know a chemical change has occurred?

Explain what you think causes planets to have weaker or stronger gravity than Earth. Predict what gravity would be like on a planet with a mass equal to Earth's but a diameter half the size of Earth's.

423.3 mL of gas is at 49.2 C. It is compressed to a volume of 79 mL. What is the new temperture. Express your answer in Kelvin.

Which of the following is a contact force? A. Gravity B. Magnetism C. Friction D. Electrical force

If a ball has a velocity of 15 m/s and a kinetic energy of 225 J, what is the mass of the ball?

Heat given off by a fire in a fireplace is an example of a. conduction. b. radiation. c. insolation. d. convection.

Name 4 common chemical properties of matter

Why is photosynthesis so important to plants, and can't animals use it?

One way the government of Kim Jong-il controls the lives of the people who live in North Korea is by a. requiring every citizen to vote. b. controlling information its people receive from the outside world. c. enforcing free trade with other nations.

Give reasons 1) copper utensils and sheets become blackish after some days

Predict the spontaneity of a reaction (and the temperature dependence of the spontaneity) for each possible combination of signs for? H and? S (for the system).