2. The digestive system performs chemical
and physical changes on food ingested.
Which of the following is a physical change
that occurs during human digestion?
• A Amylase in the saliva
breaks down starches.
• B Cells lining the stomach
release pepsin to break
down proteins.
• C Bile produced in the liver
breaks down lipids.
• D Molars pulverize food,
grinding it into a paste.
3. In the model of this
molecule, what does CH3
represent?
• A 1 carbon and
3 hydrogens
• B 3 carbons and
3 hydrogens
• C 1 calcium and
3 heliums
• D 3 chlorines
4. • Carbon
• Hydrogen
• Oxygen
• Answer: 3
How many elements are present in
the following reaction?
C3H8 + 5O2 -> 3CO2 + 4H2O
5. Which could be a description
of the subatomic particle
found at location X?
• A. It has mass but no
charge.
• B. It has no mass and a
positive charge.
• C. It has a large mass and a
negative charge.
• D. It has no mass and an
equal number of positive
and negative charges.
6. A student observes some sugar as it is heated and
burns. The student concludes that a chemical
reaction has occurred. Which of the following
observations about the burning sugar provides
evidence of a chemical reaction?
A. Heat is added to the
sugar crystals.
B. The sugar melts and
becomes liquid.
C. The temperature of
the sugar increases.
D. Gas is produced as
the sugar turns black.
7. In the diagram, a wind turbine is transferring energy
from the wind. Between which two steps in the diagram
is mechanical energy being converted into electrical
energy?
A. 1 and 2
B. 2 and 3
C. 3 and 4
D. 4 and 5
