1. Atoms, Molecules, Pure Substances, & Mixtures
CRCT Prep
Part I

2. B. an element. C. a mixture. D. a compound.
A scientist combines oxygen and hydrogen to form water. This combination illustrates that water is
A. an atom.
B. an element.
C. a mixture.
D. a compound.

3. A. the atom B. the electron C. the nucleus D. the proton
Copper is an element that is sued in electrical wires. What is the smallest unit of copper that still maintains the characteristics of copper?
A. the atom
B. the electron
C. the nucleus
D. the proton

4. A. atom B. molecule C. neutron D. proton
What is the smallest particle of the element gold (Au) that can still be classified as gold?
A. atom
B. molecule
C. neutron
D. proton

5. Which of the following illustrations represents a pure substance?
A B.
C D.

6. Which formulas represent compounds?
A. O2, H2O2
B. CO2, H2O
C. H2, CO2
D. H2, O2

7. If different kinds of atoms are represented by different colored dots, which picture represents a sample of a compound?
A B.
C D.

8. If different kinds of atoms are represented by different colored dots, which picture below represents a mixture?
A B.
C D.

9. Which of the following is a compound?
A. oxygen
B. water
C. nitrogen
D. air

10. A mixture of powdered iron and sulfur reacts chemically when heated
A mixture of powdered iron and sulfur reacts chemically when heated. What will be formed?
A. a single element
B. two other elements
C. a solution
D. a compound

11. A solution in a dish contains 3
A solution in a dish contains 3.0 grams of salt dissolved in 100 grams of water. If 50 grams of the water evaporate, the solution is
A. a compound.
B. a mixture.
C. an element.
D. a solid.

12. Carbon dioxide is
A. an element.
B. a compound.
C. a solution.
D. a mixture.

13. A chemical change combining two elements results in
A. an atom.
B. a compound.
C. an element.
D. a mixture.