Matter and Energy #1

Density is a property of matter?

• true

• false

The scientist spilled a few drops of dilute acid on a lab table. For safety purposes, the scientist sprinkled some baking soda onto the spill. Which observation would provide the best evidence that a chemical reaction occurred?

• The baking soda and acid combined, and bubbles formed.

• The baking soda absorbed the acid.

• Some of the baking soda dissolved in the acid.

• The acid evaporated, leaving only the baking soda.

A student observes some sugar as it is heated and burns. The student concludes that a chemical reaction has occurred. Which of the following observations about the burning sugar provides evidence of a chemical reaction?

• Heat is added to the sugar crystals.

• The sugar melts and becomes a liquid.

• The temperature of the sugar increases

• Gas is produced as the sugar turns black.

The chemical equation shown below represents a reaction that produces fuel for certain cars.

CO + H₂O ---> CO₂ + H₂

_{Which of these represents an element?}

• CO

• H₂O

• CO₂

• H₂

Weight is the measure of the pull of _____________ on an object.

• scale
• gravity
• mass
• force

When a gas becomes a liquid

• Evaporation
• Boiling
• Freezing
• Condensation

When a solid becomes a liquid

• Sublimation
• Evaporation
• Melting
• Freezing

What kind of energy?

• Thermal (kinetic) energy
• Chemical (kinetic) energy
• Chemical (potential) energy
• Mechanical (kinetic) energy

Dissolving salt is a

• Chemical change

• Physical change

The production of carbon dioxide gas when baking soda and vinegar reacted indicated a _____________.

• Chemical change

• Physical change