What do these two changes have in common?
a slice of banana turning brown
grilling a hamburger
A: Both are chemical changes.
B: Both are caused by heating.
C: Both are caused by cooling.
D: Both are only physical changes.
Step 1: Think about each change.
A slice of banana turning brown is a chemical change. The part of the banana in contact with the air reacts with oxygen and turns into a different type of matter.
Grilling a hamburger is a chemical change. Heat from the grill causes the matter in the meat to change. Cooked meat and raw meat are different types of matter.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are chemical changes. They are not physical changes.
Both are chemical changes.
Both changes are chemical changes. The type of matter before and after each change is different.
Both are caused by heating.
Cooking a hamburger is caused by heating. But a slice of banana turning brown is not.
Both are caused by cooling.
Neither change is caused by cooling.