Physical vs. Chemical Changes

What is a physical change?

• A change that affects chemical properties

• A change that only affects physical properties

• A process that forms new substances

• A chemical reaction.

What is a chemical change?

• A change that affects physical properties

• A change that affects chemical properties and forms a new substance

• A process that does not involve a chemical reaction

• A change that only affects appearance.

Fill in the blank: A chemical reaction is a process by which the atoms of one or more substances are rearranged to form ________.

• different substances.

• the same substances.

• a mixture of reactants.

• a complete set of unchanged elements.

What are chemical reactions represented by?

• Equations

• Symbols

• Numbers

• Letters

In the chemical equation 2Na(s) + Cl2(g) → 2NaCl(s), what are the reactants?

• 2NaCl(s)

• 2Na(s) and Cl2(g)

• Cl2(g) and 2NaCl(s)

• 2Na(s) and 2NaCl(s)

Fill in the blank: In a chemical reaction, reactants are the starting substances, also known as "ingredients."

• reactants

• products

• compounds

• elements

What does the coefficient in a chemical equation tell us?

• The type of reaction

• The number of each substance needed

• The temperature of the reaction

• The color of the substances

Fill in the blank: In the chemical equation 2Na(s) + Cl2(g) → 2NaCl(s), the coefficient '2' in front of Na indicates that 2 Na atoms are needed for this reaction, but only ___ Cl2 molecule is needed.

• 1

• 2

• 3

• 4

What does the notation (s) represent in a chemical equation?

• A) Solid

• B) Liquid

• C) Gas

• D) Aqueous

What does the notation (l) represent in a chemical equation?

• A) Solid

• B) Liquid

• C) Gas

• D) Aqueous