Powers 7th Assessment PS1-5

First & Last Name

1. The Law of Conservation of Mass means

• Mass = chemical reaction + 5
• Total number of atoms does not change after a chemical reaction, and because of this, mass is conserved
• Structure of molecules stays the same between reactants and products in a chemical reaction
• Mass changes after a chemical reaction

2. If you combine two substances

• The combined weight will be greater than the weight of each individual substance.
• The combined weight will be the same as the weight of the two individual substances.
• The combined weight will decrease.
• The combined weight will increase.

3. When a chemical reaction occurs by adding two substances together

• The state of matter changes from solid to liquid
• The weight of the new substance will increase
• A new substance is created
• The weight of the result will decrease

4. Regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved.

• true
• false

5. We know that matter is conserved in a chemical reaction because

• Mass is conserved
• The total number of atoms in the product is the same as the atoms in the combined reactants
• We can demonstrate this by counting the atoms before and after a reaction
• We can make a model to show that matter is conserved
• All if the above

6. Look at this equation. H2 + O2 = H2O

• Mass is not conserved
• Mass is conserved. The atoms are just rearranged in the product
• We cannot tell by looking at this equation