Answers to Study Guide
1. C
A solid is dense because the atoms are packed closely together. This also explains why it cannot
be compressed.
2. C
Lucky Charms are an uneven mixture. You can clearly see the different types of matter in it, so it
must be heterogeneous.
3. A
It’s a physical change because the water never changes into a different chemical. It was H20 the
whole time. These changes are also easily reversible.
4. A.
“Breaking down” means there is a chemical change going on. Food being digested goes through
a chemical change (think about what is…left over. It’s clearly a completely different type of
matter than what you ate). The other three choices are physical changes.
5. B
Material Safety Data Sheet
6. D
Intensive properties are properties that do not change depending on the amount of matter
present. Remember: “Intensive properties are too intense to change.” None of the answer
choices would change depending on the amount of matter.
7. A
Extensive properties are properties that change depending on the amount of matter present. B,
C and D are intensive, and do not change.
8. A
Lemonade is homogeneous because it is an even mixture. The pasta and sauce is an uneven
mixture, so it is heterogeneous.
9. B
There are two types of pure substances: elements and compounds. If more than one element
makes up that pure substance, it must be a compound.
10. C
Chlorine is on the periodic table, so it is an element.
11. A
Compounds are “chemical combos.” They also have a chemical formula. Answers A and C both
have a formula, but only A shows that there is more than one element bonded together.
Saltwater is a homogeneous mixture. An oak tree is made of many compounds and mixtures.
12. B
This is one is kind of tough. Color change is one of the signs of a chemical change. You may be
thinking that the matter (hair) didn’t turn into a different type of matter – and you are right;
however, the pigment in the cells that gives the hair its color goes through a chemical change.
(This is similar to the leaves changing color (which is also a chemical change). The leaves don’t
turn into a different type of matter, but the chlorophyll in the cells goes through a chemical
change)
13. D
The atoms of liquids and gases move around freely, so they take the shape of their container.
14. D
Cooking is a chemical change. In fact, that is one reason we cook our food: our bodies handle
the chemicals of cooked food better than raw food.