Unit B Section 1.3

Question 1

physical change?

Answer 1

A physical change is one in which a material changes from one state to another. The material can also physically change back into its original state.

Question 2

chemical change?

Answer 2

A chemical change occurs when two or more materials react and create new materials. The new materials have completely different properties from the original substances.

Question 3

Evidence of Chemical Change

Answer 3

• Change in colour (bleach)
• Change in odour (striking match)
• Formation of a solid or gas(vinegar+baking s=CO2 gas)
• Release or absorption of heat energy (gasoline in car)

Question 4

Freeze-drying? (example of controlling matter)

Answer 4

Freeze-drying is a way to preserve foods so that they can be eaten for months, you have to do is add hot water

-The result is that about 98% of the water in the original food item is removed.

Question 5

U.S. Army, makes freeze-dried food?

Answer 5

“Meal, Ready to Eat” (also referred to as an MRE) is
heated in a special package called a “Flameless Ration Heater.” This makes MREs especially useful for soldiers, astronauts, and mountain climbers.

Question 6

How do chemicals made from corn can be used to make soda pop bottles, remove paint or nail polish, and fuel some cars?

Answer 6

Corn is put through a chemical change called fermentation.