8th Grade Science Released Tests

Tearing paper is an example of a —
1. physical change
2. chemical change
3. chemical reaction
4. solution
A substance made up of two or more elements that have been chemically combined is called —
1. an atom
2. a compound
3. an element
4. a mixture
Because zinc can combine with other substances but cannot be changed into a simpler substance by an ordinary chemical process, zinc is classified as —
1. a compound
2. a mixture
3. an element
4. an acid
A student makes a drawing of a carbon atom. Which of these should the student show in the nucleus of the atom?
1. Ions
2. Protons
3. Electrons
4. Molecules
Which of the following elements belongs to the family indicated?
1. Nitrogen belongs to the halogen family.
2. Helium belongs to the noble gas family.
3. Calcium belongs to the alkali family.
4. Sodium belongs to the alkaline earth family
Which picture illustrates the structure of a molecule of water?
Which of these substances is an element?
1. Steel
2. Chlorine
3. Plastic
4. Sugar
After fishing in the ocean, a student left his fishing gear in the sun to dry. Later, he noticed that small white crystals had formed on the rod, reel, and fishing line. Which of these is the best explanation of what occurred?
1. The water evaporated from the fishing gear, and sand was attracted to it.
2. The fish that were caught left scales on the fishing gear.
3. The salt in the ocean water reacted with the fishing gear and caused it to rust.
4. The water evaporated from the fishing gear, and salt from the ocean was left behind.
In the chemical formula for ammonia, , what does the subscript 3 represent?
1. The number of nitrogen and hydrogen atoms in each molecule of ammonia
2. The number of hydrogen atoms in each molecule of ammonia
3. The number of ammonia molecules that will bond together
4. The number of nitrogen atoms in each molecule of ammonia
Mercury is a liquid metal that is used in many thermometers. The mercury in the thermometer rises because it —
1. is sucked upward by vacuum
2. expands when heated
3. is compressed by air pressure
4. increases in density when heated
Which of these will cause water to change to ice?
1. Removing heat from the water
2. Stirring the water
3. Adding salt to the water
4. Putting the water in the sunlight
Which process is a physical change?
1. Rusting iron
2. Burning coal
3. Tarnishing silver
4. Melting ice
Expansion joints such as these are put on bridges because the concrete expands and contracts. This happens when —
1. chemicals get on the concrete
2. the temperature changes
3. the amount of light changes
4. the concrete gets wet
Which of the following is a physical property of copper?
1. Ductile, can be drawn into a wire
2. Liquid at room temperature
3. Readily reacts with water to form an acid
4. Readily reacts with oxygen
Which of these elements has an atomic number of 14?
1. N
2. Al
3. Si
4. P
Several centuries ago, men called alchemists tried to transform common metals into gold. Even though they tried many different chemical and physical methods, they never succeeded because —
1. they could not heat common metals to extremely high temperatures
2. the common metals they worked with were not pure
3. they did not add the correct material to the common metal
4. elements cannot be changed to other elements by physical or chemical means
The atom is composed of electrons, protons, and neutrons. What is the electric charge on the neutron?
1. -1
2. +1
3. 0
4. +2

8th Grade Science Released Tests - Matter Review 1