Chemical and Physical Changes

A different chemical substance is formed when...

• a cloth is cut
• a cup breaks
• a candle burns
• a piece of chalk falls apart

When water in an open pan is heated for a long time, it becomes

• a solid
• a vacuum
• a gas
• dew

Which object is most likely to rust?

• an iron nail
• a plastic comb
• a glass marble
• a paper cup

Which of the following is an example of MELTING?

• stirring some sugar in water until you cannot see the sugar
• heating a pan of water until the water is all gone
• heating a block of ice until the ice turns to water
• cooling water in the freezer until the water becomes solid

David added a little baking soda to a beaker that contained vinegar.  Bubbles started coming from the mixture as a gas was released.  The gas was evidence that

• the mixture was starting to boil.
• the air in the flask contracted.
• a chemical reaction took place.
• the vinegar and baking soda expanded.

Iron is most likely to rust when it is

• damp
• dry
• painted
• covered with grease

An example of a liquid turning into a gas is

• a chocolate bar melting
• an ice cream cone dripping
• a stick of butter getting warm
• steam escaping from a cup of hot chocolate

Use the table to answer this question.              
Vinegar is an acid that bubbles when it interacts with calcite.  Which mineral contains calcite?

• limestone
• sandstone
• granite
• gneiss

If you dissolved a lot of salt in some water in a large flat dish and put the dish in bright sunlight on a hot day, what would be left in the dish after a long time?

• dry salt
• water with no salt
• the same salty water as before
• nothing

Mark is observing a burning candle.  He notices that the candle wax makes a pool and dribbles down the side of the candle, where it hardens again.  The candle was has undergone

• a physical change
• a chemical change
• a physical and a chemical change
• the formation of a new substance