Modified - Science Semester Exam

Front

What happens to the size of a balloon when heat energy is removed?

Back

The balloon shrinks because the molecules come closer together.

Front

What is the molecular arrangement of a substance when heat energy is added?

Back

The molecules are farther apart.

Front

How many carbon atoms are in the formula 3C2H6?

Back

3 carbon atoms.

Front

What does it mean when the temperature of a substance remains constant during a phase change?

Back

The substance is undergoing a change in state, but its temperature does not change.

Front

What evidence did Alfred Wegener use to support his theory of continental drift?

Back

He used glacier scars, fossil evidence, and climate evidence.

Front

What is the relationship between predator and prey populations?

Back

If a disease strikes the predator population, the prey population (e.g., rabbits) will likely increase.

Front

What is heat energy?

Back

Heat energy is the energy that comes from the temperature of matter.

Front

What happens to molecules in a gas when heat energy is added?

Back

The molecules move faster and spread apart.

Front

What is the significance of constant temperature during a phase change?

Back

It indicates that the substance is changing from one state to another, such as solid to liquid.

Front

What is the formula for calculating the number of molecules in a compound?

Back

Count the coefficients and subscripts in the chemical formula.