Which best describes the definition for the atomic mass of an element
a. it is a ratio based on the mass of the carbon 12 atom
b. it is a weighted average of the masses of an elements isotopes
c. it is twice the number of protons in one atom of the element
d. it is the sum of the protons and neutrons in one atom of the element

The agent of mechanical weathering in which rock is worn away by the grinding action of other rock particles is call

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?