The half life of a certain substance is 28 years. how long will it take for a sample of this substance to decay to 78% of its orginal amount.

Which of the following best explains why the end of a spoon sticking out of a cup of hot water also gets hot? question 7 options: the heat from the hot water is conducted through the spoon handle the hot water heats the air surrounding the upper part of the spoon. the hot water causes a physical change in the spoon handle. the hot water causes a chemical reaction to take place in the spoon.

List four observations that indicate that a chemical reaction may be taking place

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