Physical Science GED Practice

Physical Science GED Practice

Physical science (chemistry and physics) makes up 40% of the GED Science subject test. Test your knowledge with these physical science GED practice questions (answer key at the end of the post). Also check out these tips for GED Science success.

Physical Science GED Practice Questions

1. How many total atoms of hydrogen are in one molecule each of H2O and C6H12O6?

A) 2
B) 7
C) 12
D) 14

2. An ion has 12 protons and 14 neutrons. This ion will have an overall positive charge if its number of electrons equals

A) 11
B) 12
C) 13
D) 14

Questions 3-4 are based on the information and table below.
Phases of Matter
Solid, liquid, and gas are the three main states of matter. The molecules in solids are held together by very strong bonds; therefore, they have the most densely packed, slowest-moving particles. Gas molecules, on the other hand, are held together by weak bonds, so gases have the least densely-packed, fastest-moving particles.

Matter can undergo physical changes to convert from one phase to another.

A change from a... ... to a... is called...
solid liquid melting
solid gassublimation
liquid solid freezing

Exothermic and Endothermic Reactions
An exothermic reaction is a process in which heat is released and chemical bonds are formed. An endothermic reaction is one in which heat is absorbed and chemical bonds are broken.

3. Which of these processes results in a substance with slower-moving molecules after the change?

A) Melting
B) Sublimation
C) Vaporization
D) Condensation

4. Which of these is an exothermic reaction?

A) Melting
B) Freezing
C) Vaporization
D) Sublimation

5. 0 degrees Kelvin (0K) is a temperature with a special name—absolute zero. Absolute zero is the lowest possible temperature—the temperature at which all motion would theoretically cease. Absolute zero is equal to -273°C. If water boils at 100°C, what is the boiling point of water on the Kelvin temperature scale?

Question 6 is based on the following information and illustration.
Energy is defined as the ability to do work. The total energy of a system is made up of potential energy and kinetic energy. Potential energy is stored energy based on position and the potential to perform work. Kinetic energy is energy due to motion.
Physical Science GED Practice: Roller Coaster- Magoosh
Based on image by GDJ.

6. At which point on the roller coaster does the car have the greatest amount of potential energy?

A) A
B) B
C) C
D) D

7. Newton’s Second Law of Motion states that acceleration is directly proportional to the net force if the mass is constant. Therefore, assuming mass remains the same, if the net force decreases, acceleration will

A) increase
B) decrease
C) stay the same

Question 8 is based on the information and diagram below.
A lever is a type of simple machine that makes it easier to move a load. A lever consists of a beam balanced on a fixed point called a fulcrum. There are three types of levers:

  • Class A: The fulcrum is in the middle of the beam, with effort applied on one end and the load resting on the other end.
  • Class B: The load is in the middle. Effort is applied on one side of the load and the fulcrum is located on the other.
  • Class C: Effort is applied in the middle. The load is on one side and the fulcrum is located on the other.

Physical Science GED Practice: Lever- Magoosh
Image by Koltepranita.

8. Which type of lever is shown in the diagram?
A) Class A
B) Class B
C) Class C

Answer Key

1. D
The number in a subscript after each letter in a chemical formula indicates the number of atoms of that element in a single molecule. A molecule of H2O has 2 hydrogen (H) atoms, and a molecule of C6H12O6 has 12 hydrogen atoms. 2 + 12 = 14.

2. A
An ion is an atom with an unequal number of protons and electrons, giving it a positive or a negative charge. Normally, an atom has an equal number of positively-charged protons as negatively-charged electrons, giving the atom an overall neutral charge. In an ion, however, some electrons have either been gained or lost, which throws off the balance and gives the ion a charge. If there are more protons than electrons, the ion will have a positive charge (and be called a cation). If there are more electrons than protons, the ion will have a negative charge (and be called an anion). In this case, we’re looking for a positive charge, so we need a number of electrons that is less than the number of protons, which is 12. The only choice less than 12 is 11.

3. D
Condensation involves a slowing-down of molecules. Condensation is the process of a gas turning into a liquid. Gas molecules move more quickly than liquid molecules, so the phase change results in slower movement.

4. B
Freezing is the process of a liquid turning into a solid. Since a solid has stronger bonds than a liquid, bonds are being formed rather than broken in this process. An exothermic reaction creates molecular bonds.

5. 373K
The size of Celsius degrees and Kelvin degrees are equal, so you only need to use addition to solve. The question tells you that 0K = -273°C, so to convert from Celsius to Kelvin, you need to add 273. The boiling point of water in Celsius is 100°C, so the boiling point of water in Kelvin is 100 + 273 = 373K.

6. A
At the highest point of the roller coaster, the car would briefly stop. When not in motion, it would have total potential energy and not kinetic energy. As the car then began its descent, that potential energy would be converted to kinetic energy. On the next, lower hill, the car would again have some potential energy but inertia would keep it moving, so it would still maintain kinetic energy.

7. B
The question states that acceleration and force are directly proportional. If two things are directly proportional, they move in the same direction. So if one increases, the other also increases, and if one decreases, the other also decreases. In this case, the force decreases, so acceleration will also decrease.

8. A
The diagram shows a lever with the fulcrum in the center and effort applied on one end to lift a load on the other end. This matches with the given description of a Class A lever.


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    Sarah is an educator and writer with a Master’s degree in education from Syracuse University who has helped students succeed on standardized tests since 2008. She loves reading, theater, and chasing around her two kids.