This diagram shows the chemical reaction that takes place when a candle is burning. What are the reactants in this reaction?

• Oxygen and candle wax

• Carbon dioxide and water (vapor)

• Oxygen and heat

• Dark zone and luminous zone

In this chemical reaction, iron and oxygen react to make iron oxide (rust). What is the product of the reaction?

• Iron

• Oxygen

• Iron and oxygen

• Iron oxide (rust)

How many hydrogen atoms are there on the reactant and product sides of the photosynthesis equation?

• Reactants (2 atoms), products (12 atoms)

• Reactants (6 atoms), products (12 atoms)

• Reactants (12 atoms), products (12 atoms)

• Reactants (6 atoms), products (6 atoms)

Is this equation balanced?

• Yes, it is balanced

• No, it is not balanced

• It is 50% balanced

• It is 75% balanced

Is this equation balanced?

• Yes, it is balanced

• No, it is not balanced

• Equations are always balanced

• It is 25% balanced

Butane is made out of four carbons and ten hydrogen. What is the molecular formula?

(The molecular formula shows all of the atoms in a molecule)

• CH₄

• C₂H₅

• C₄H₁₀

• Butane has no molecular formula

Glucose (sugar) is made of six carbon atoms, twelve hydrogen atoms, and 6 oxygen atoms. What is the empirical formula for glucose?

(The empirical formula is a ratio of the elements in a molecule)

• CH₂O

• C₆H₁₂O₆

• CHO

• Sugar is not real

What is the Law of Conservation of Mass?

• Matter can be created and destroyed

• Matter can't be created but it can be destroyed

• Matter can be created but not destroyed

• Matter can't be created and can't be destroyed

How can you tell that a chemical reaction is taking place in this picture?

• There is a change of color

• There is a change in temperature

• Bubbles have been formed

• A solid has been formed

How can you tell that a chemical reaction has taken place in this picture?

• Change of color

• Change of temperature

• Bubbles formed

• Solid formed