Front

What is the law of conservation of energy?

Back

The law of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another.

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances, often indicated by fizzing, foaming, or burning.

Front

How many atoms are in the reactants of the equation CH₄ + 2O₂ → CO₂ + 2H₂O?

Back

There are 9 total atoms on the reactant side (1 carbon atom and 8 oxygen and hydrogen atoms).

Front

What happens to thermal energy when a hot pan is placed on a cold counter?

Back

Thermal energy is transferred from the hot pan to its surroundings, including the counter and the air, until thermal equilibrium is reached.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance made of only one type of atom, while a compound is a substance formed when two or more different elements are chemically bonded together.

Front

What is an example of a physical change?

Back

Melting ice is an example of a physical change, as it changes from solid to liquid without altering its chemical structure.

Front

What is an example of a chemical change?

Back

Rusting of iron is an example of a chemical change, as it forms a new substance (iron oxide) through a chemical reaction.

Front

What is the definition of a molecule?

Back

A molecule is a group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.

Front

What is the role of a catalyst in a chemical reaction?

Back

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.