Chapter 4 Earth Chemistry Review Answer Key
SECTION 1 MATTER
Review
1.
first row: Electron second row, from left to right: +; –; none third row: in the nucleus
2.
Physical properties can be observed without chemical reactions. Chemical properties can be
observed only when a substance reacts with another substance.
3.
The atom’s mass number is 29. It is an atom of silicon. Silicon’s atomic number is 14, so all atoms
of silicon have 14 protons.
4.
Isotopes have the same number of protons, so their atomic numbers are equal. Isotopes have
different numbers of neutrons, so their mass numbers are different.
5.
They have the same number of valence electrons, and they have similar properties.
SECTION 2 COMBINATIONS OF ATOMS
Review
1.
second row, from left to right: compounds; mixtures third row, from left to right: covalent bonds;
ionic bonds; heterogeneous; homogeneous
2.
The reactants are hydrogen (H
2
) and oxygen (O
2
). The product is water (H
2
O). The equation is
balanced because there are four hydrogen atoms and two oxygen atoms on each side of the
equation.
3.
Possible answers: Coffee is an example of a homogeneous solution. Gravel is an example of a
heterogeneous solution.
Chapter 5 Minerals Review Answer Key
SECTION 1 WHAT IS A MINERAL?
Review
1.
Silicate minerals contain compounds of silicon and oxygen. Nonsilicate minerals do not.
2.
cubes, hexagonal prisms, and irregular shapes
3.
Possible answer: Diamonds are minerals. They are solid, they form naturally, and they form
crystals.
4.
sulfides
5.
Quartz is a silicate mineral, so quartz is made up of silicon-oxygen tetrahedrons. In a framework
silicate such as quartz, each silicon-oxygen tetrahedron shares four oxygen atoms with other
tetrahedrons. The tetrahedrons form a web, or framework. In a single-chain silicate such as
pyroxene, each tetrahedron shares two oxygen atoms with other tetrahedrons. The tetrahedrons
form long chains.
6.
They do not contain silicon. All silicate minerals contain silicon and oxygen bonded together.
SECTION 2 IDENTIFYING MINERALS
Review
Review
1.
cleavage only: mineral breaks along smooth, flat surfaces cleavage and fracture: describes how a
mineral breaks fracture only: mineral breaks along uneven surfaces
2.
If you scratched a piece of gold with a piece of talc, nothing would happen. The talc would not
scratch the gold. Both the calcite and the quartz would scratch the gold.
3.
A mineral may have many different colors, but its streak is always the same, no matter what its
color is.
4.
double refraction
Chapter 6 Rock