Law of Conservation of Matter Spiral Review

20g of sugar is stirred into a beaker containing 100 g of water. After the sugar has completely dissolved, the solution is put on the scale. What is the mass of the solution ?

• 20 g

• 80 g

• 100 g

• 120 g

Compare the box on the left containing the reactants in a chemical reaction. Which box on the right is the correctly represents the products according to the Law of Conservation of Mass?

• A

• B

• C

• D

Based on the Law of Conservation of Matter, describe the relationship between the mass of the reactants and the mass of the products.

• The mass of the reactants equals the mass of the products.

• The mass of the reactants is less than the mass of the products.

• 
  The mass of the products is always greater than the mass of the reactants.

• The mass of the reactants is greater than the mass of the products; some mass is lost when atoms recombine.

Erica and Jim are given a closed container of ice. They find the mass of the container and ice to be 28.0 grams. The container of ice is left on the lab table overnight. The next day, Erica and Jim observed the container. All of the ice had melted. They place the container back on the balance and found the mass to be

• more than it was since the ice had melted.

• the same as it was the day before.

• more than it was since a new compound was formed.

• 
  less than it was since the container was full of liquid.

The law of conservation of matter tells us that the total number of atoms does not change in a chemical reaction and thus mass is conserved. Select ALL of the reactions that obey the law of conservation of matter.

• 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

• 
  8 H₂S + 8 Cl₂ → S₈ + 16 HCl

• 
  CH₄ + 2 O₂ → CO₂ + H₂O

• 
  HCl + K₂CO₃ → KCl + H₂O + CO₂

• 2 Al(OH)₃ + 3 H₂SO₄ → Al₂(SO₄)₃ + 6 H₂O