Does every scientific method begin with an observation? explajn.

If an atom has a mass number of 23, which of the following is always true? The number of protons in the nucleus does not equal the number of neutrons. The atomic number is less than 11. The atom is not an isotope.

What happens if heat flows into matter when no change of state is involved? a. both thermal energy and temperature increase b. both thermal energy and temperature decrease c. thermal energy decreases, temperature increases d.

Which mission saw the first american spacewalk

A substance that is formed in a chemical reaction is a A product B reactant C solvent D Mixture

Seasons are a result of: Earth's rotation on its axis Earth's tilt on its axis global air circulation patterns global humidity circulation patterns

The weight of an object varies inversely with the second power of the distance from the center of Earth. The radius of Earth is approximately 4000 miles.

The chemical reaction of oxygen with other substances is called A. erosion. B. oxidation. C. exfoliation. D. acidification.

Find the net charge of a system consisting of 6.16*106 electrons and 7.68*106 protons. Express your answer using three significant figures. Qnet = 2.43*10-13 C

A motorist is driving at 20m/s when she sees that a traffic light 200m ahead has just turned red. She knows that this light stays red for 15s, and she wants to reach the light just as it turns green again. It takes her 1.

Does sound move as a longitudinal or transverse wave in a medium?