VP#3: Balancing equations and the Law of Conservation of Matter

What is a chemical equation?

• A chemical equation shows what and how much is involved in a chemical reaction.

• A chemical equation is a representation of a physical or chemical change.

• A chemical equation describes the color of a substance.
• A chemical equation is a recipe for cooking.

What does the law of conservation of mass state about matter in a chemical reaction?

• Matter can be created or destroyed.

• Matter changes its form but is not created or destroyed.

• Matter is only created during a reaction.

• Matter is only destroyed during a reaction.

Why do we balance chemical equations?

• To increase the speed of the reaction.
• To change the state of the reactants.
• To determine the temperature of the reaction.
• To ensure the amounts of atoms at the start and end of the reaction are equal.

What do the subscripts in the chemical equation mean?

• Subscripts indicate the temperature of a reaction.
• Subscripts show the charge of each element in a compound.
• Subscripts represent the state of matter for each element.
• Subscripts represent the number of atoms of each element in a molecule.

The coefficients in the chemical equations are ______________ to each of the atoms in the molecule.

• applied
• ignored
• removed
• altered

What is the first step in balancing a chemical equation?

• Count the number of atoms in the product.

• Change the subscripts of the elements.

• Write the unbalanced equation.

• Add coefficients to balance the equation.

Why should you never change the subscripts in a chemical equation?

• It makes the equation look messy.

• It changes the identity of the substances.

• It makes balancing easier.

• It is not allowed in chemistry.

What is the least common multiple of 3 and 5?

• 12
• 10
• 15
• 20

How do you balance bromine in the reaction with aluminum?

• Add a coefficient of 2 to bromine.

• Add a coefficient of 3 to bromine.

• Find the least common multiple of 2 and 3.

• Change the subscript of bromine to 6.

What is the final step after balancing a chemical equation?

• Remove all coefficients to simplify the equation.

• Add more coefficients to the product side.

• Check your work to ensure both sides are balanced.

• Change the subscripts to match the coefficients.