Thermal energy #3

What happens to the molecules of a substance as it gets cooler?

• The molecules shrink

• The molecules expand

• The molecules move faster

• The molecules move slower

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit
• Invisible
• Transformed, changed
• None of the above

How many grams of coal were present at the start of the chemical change?

• Unknown

• 100 g

• 200 g

• 50 g

A chemical reaction that releases energy _________ and a chemical reaction that absorbs energy is called _____________.

• exothermic; endothermic

• endothermic; exothermic

• exothermic; accumulative

• liberal; endothermic

If 10 grams of water are added to 5 grams of salt, how much salt water will be made?

• 2 grams
• 5 grams
• 10 grams
• 15 grams

Which of the models of a chemical reaction best represents the Law of Conservation of Mass?

• A

• B

• C

• D

Where is potential energy the highest?

• W 
• X
• Y
• Z

Where is kinetic energy the highest?

• W 
• X
• Y
• Z

substance that exists after a chemical reaction

• product

• reactant

• reactivity

• relation