Weekly Assignment #4: Matter, Physical and Chemical Properties and Changes, Elements and
Compounds, and Mixtures and Pure Substances
Directions: On a separate piece of paper please answer all of the following problems. You DO NOT need
to turn this paper in with you work.
DUE: Friday October 7th
1. We define ___________________ as anything that has mass and occupies space.
2. What states of matter are virtually incompressible to smaller volumes? Which state of matter is
compressible?
3. In which state of matter are the molecules essentially in a fixed position? In which states of matter
are the molecules able to move around freely?
4. What similarities are there between the liquid and gaseous states of matter? What differences are
there between these two states?
5. Copper is a reddish-brown metal that is easily stretched to make wires. These characteristics are
examples of (chemical or physical) properties of copper.
* (For problems 6 and 7) Aqueous solutions of the substance potassium dichromate are bright orange in
color. If potassium dichromate solution is added to an acidic solution of iron (II) sulfate, the orange
color of the potassium dichromate disappears, and the mixture takes on a bright green color as the
chromium (III) ion forms.
6. From the information above, indicate one PHYSICAL property of potassium dichromate in solution.
7. From the information above, indicate one CHEMICAL property of potassium dichromate in solution.
8. Describe on a microscopic basis, the changes that take place when an ice cube is heated strongly until
it melts and the water vaporizes. Why are these changes PHYSICAL and not CHEMICAL in nature?
9. Classify the following as physical or chemical changes:
a. Mothballs gradually vaporize in a closet
b. A French chef making a sauce with brandy is able to burn off the alcohol from the brandy,
leaving just the brandy flavoring
c. Hydrofluoric acid attacks glass, and is used to etch calibration marks on glass laboratory
utensils
d. A flash light battery corrodes and leaks on prolonged storage.
e. Whole milk curdles if vinegar is added to it
10. Elements cannot be broken down into simpler substances by __________________ means.
11. What does it mean to say that a given compound always has the same composition.
12. Give 3 examples of a heterogeneous mixture and three examples of a homogenous mixture.
13. Identify the following as mixtures or pure substances:
a. milk
b. the paper this homework assignment is printed on
c. a teaspoon of sugar
d. steel
14. Classify the following mixtures as homogeneous or heterogeneous.
a. gasoline
b. a jar of jelly beans
c. chunky peanut butter
d. margarine