Physical and Chemical Changes

Which is a chemical change?

• Frying an egg
• Boiling water
• Breaking a glass cup
• Crushing a piece of bread

Which best explains why burning leaves is a chemical change?

• The leaves emit light during the change.
• The temperature of the leaves increases.
• The shape of the leaves changes.
• The leaves turn to ashes.

Which example shows a new substance being formed?

• a candle burning
• a shoelace being tied
• 
  a pipe being cut in half
• a block of ice melting

Water is boiled and turns to vapor. The vapor is cooled and changes back into water. Which best describes what has occurred?

• a physical change, because the matter changed its state
• a chemical change, because the matter changed its state
• 
  a physical change, because a new substance was formed
• a chemical change, because a new substance was formed

A piece of wood is sawed into several small pieces. This is an example of what kind of change?

• physical
• chemical
• electrical
• mechanical

Physical and chemical properties can be used to classify substances. Which of these shows a chemical property?

• Silver melts.
• Magnesium burns.
• Sulfur is a yellow solid.
• Aluminum conducts heat.

Which of these is an example of a new substance being formed?

• a nail rusting
• a wall being painted
• water changing to steam
• paper being folded

Which change is most likely to produce a new substance?

• a piece of paper burning
• sugar dissolving into water
• glass breaking into many pieces
• water boiling and creating steam

A student placed an egg in a container of vinegar.
Bubbles formed on the shell of the egg, and after three days, the shell was gone. Which observation made by the student indicated a chemical change took place?

• The bubbles were produced as the shell reacted with the acid.
• The vinegar solution remained clear.
• The temperature of the vinegar remained the same.
• 
  The shape of the egg remained oval.

Which statement best describes why baking a cake is an example of a chemical change?

• The process takes place in an oven.
• The process requires heat energy.
• 
  The process cannot be reversed.
• The process can be repeated.