U1 L3 - Physical & Chemical Changes

Which of the following is a chemical change?

• Painting a door red
• Dissolving salt in water
• A banana decomposing
• Bending a nail

Which of the following is a physical change?

• Exploding a stick of dynamite
• Stretching a rubber band
• Rusting a nail
• Ripening of an apple

What happens to the identity of a substance during a physical change?

• It turns into something new
• It disappears
• It does not change
• It forms new compounds

A block of wood weighs 200g.  After being burned, the ashes weigh 50g.  What is the mass of the smoke that "burned off"?

• 50g
• 150g
• 200g
• 250g

Which is a chemical change?

• Boiling water into steam
• Dissolving sugar in water
• Milk spoiling
• Dyeing a T-shirt blue

Which is a physical change?

• Melting Butter
• Baking soda mixed with vinegar
• Burning a candle
• Fireworks exploding

A banana is frozen in liquid nitrogen.

• Physical
• Chemical

Liquid nitrogen boils into gas at -195 degrees C

• Physical
• Chemical

Which is NEVER a sign of a chemical change?

• Gas Production
• Color Change
• Odor Change
• Melting

The Law of Conservation of Mass says matter...

• can be created and destroyed
• can be created but not destroyed
• can be destroyed but not created
• cannot be created or destroyed