*Physical Properties*
A student observes a rock. The rock has a mass of 75 grams, a volume of 25 mL, and a rough texture. Which of these is a physical property?
Answer: Mass, volume, and texture
Why: Physical properties can be observed or measured without changing the substance.
A student combines marbles and plastic beads in a container. Which statement best describes the result?
A. A new substance formed.
B. The materials formed a mixture.
C. The marbles changed into plastic.
D. The beads lost their physical properties.
Answer: B. The materials formed a mixture.
Why: The substances are combined but remain physically different.
A student stirs sugar into water until the sugar can no longer be seen. What type of mixture was created?
Answer: A solution
Which condition is necessary for electrical energy to flow through a simple circuit?
A. The circuit must be open.
B. The circuit must have a complete path.
C. The battery must be removed.
D. The wires cannot touch the battery.
Answer: B. The circuit must have a complete path.
An ice cube is left on a table and changes from a solid to a liquid. What process occurred?
Answer: Melting
Four objects are tested with a magnet. Three objects are attracted to the magnet, but one object is not. Which physical property is being investigated?
Answer: Magnetism
Why: Magnetism describes how a material responds to a magnet.
A student mixes paper clips and small pieces of plastic. Which property could be used to separate the paper clips from the plastic?
Answer: Magnetism
Why: The paper clips can be attracted to a magnet while the plastic cannot.
In a glass of salt water, which substance is the solute?
A. Salt
B. Water
C. Glass
D. Air
Answer: A. Salt
A student builds a circuit with a battery, wires, and a light bulb. The bulb does not light because there is a break in the path. What type of circuit does the student have?
Answer: An open circuit
Water is heated until it changes from a liquid into a gas. What process is occurring?
Answer: Evaporation
Object A has a mass of 40 g and a volume of 10 mL. Object B has a mass of 30 g and a volume of 10 mL. Which object is more dense?
Answer: Object A
Why: Both objects have the same volume, but Object A has more mass packed into that space.
A student combines two substances. After they are mixed, both substances can still be identified and separated. What evidence shows that the substances formed a mixture?
Answer: The substances kept their physical properties and can be separated.
A student compares two mixtures.
Which statement is correct?
A. Both are solutions.
B. Neither is a mixture.
C. Mixture A is a solution, but B is not.
D. Mixture B is a solution, but A is not.
Answer: D. Mixture B is a solution, but A is not.
Why: Salt dissolves evenly in water, while sand does not.
A student closes a switch, and the light bulb turns on. What happened when the switch was closed?
A. The battery stopped providing energy.
B. The circuit became complete.
C. The wires stopped conducting electricity.
D. The bulb became a battery.
Answer: B. The circuit became complete.
A cold glass of water is sitting outside on a hot day. Water droplets form on the outside of the glass. Where did the droplets come from?
A. Water moved through the glass.
B. Water vapor in the air cooled and became liquid.
C. The glass produced new water.
D. The water inside froze.
Answer: B. Water vapor in the air cooled and became liquid.
A student measures a metal cube and records the following data:
The student wants to determine how much matter is packed into a given amount of space. Which property should the student use?
Answer: Density
Why: Density describes how much mass is packed into a certain volume.
A teacher mixes four materials in a container: iron pieces, plastic beads, sand, and water. Students need to separate the materials.
Which property would be most useful for removing the iron pieces first?
A. Color
B. Magnetism
C. Volume
D. Texture
Answer: B. Magnetism
A student adds salt to water and stirs. The salt is no longer visible. Which statement provides the best evidence that a solution formed?
A. The water changed color.
B. The salt was evenly distributed throughout the water.
C. The salt disappeared permanently.
D. The water became a new substance.
Answer: B. The salt was evenly distributed throughout the water.
Three students build circuits.
Which circuit will most likely light the bulb?
Answer: Circuit 1
Why: It has an energy source and a complete path.
A student places liquid water in a freezer. After several hours, the water becomes solid ice. Which statement best explains what happened?
A. Thermal energy was removed, causing the water to freeze.
B. Thermal energy was added, causing the water to melt.
C. The water changed into a new substance.
D. The water disappeared.
Answer: A. Thermal energy was removed, causing the water to freeze.
Two objects have the same mass. Object X takes up less space than Object Y. Which statement is correct?
A. Object X is less dense.
B. Object Y is more dense.
C. Object X is more dense.
D. Both objects must have the same density.
Answer: C. Object X is more dense.
Why: When the mass is the same, the object that takes up less space has more matter packed into that space.
A student says, “When two substances are mixed together, their physical properties always change.” Which evidence best disproves the student's claim?
A. Salt disappears when mixed with water.
B. Iron remains attracted to a magnet after being mixed with another material.
C. Water takes the shape of its container.
D. Ice melts when heated.
Answer: B. Iron remains attracted to a magnet after being mixed with another material.
Why: The iron maintains its magnetic property even after being mixed with another substance.
A student says, “If I cannot see the substances in a mixture, it must be a solution.” Is the student correct?
Answer: No.
Why: A solution is a mixture in which a substance dissolves evenly, but simply being unable to see a substance does not prove that a solution formed.
A student connects a battery, two wires, and a light bulb. The bulb does not light. The student checks that the battery works and that the bulb works. What should the student investigate next?
A. Whether the circuit has a complete path
B. Whether the bulb is made of plastic
C. Whether the battery is too heavy
D. Whether the wires are a mixture
Answer: A. Whether the circuit has a complete path
A student places an ice cube in a warm room. After 30 minutes, the ice cube has become liquid water.
Which statement best explains this change?
A. The water became a new substance.
B. The ice gained thermal energy and changed from a solid to a liquid.
C. The ice lost thermal energy and changed into a gas.
D. The mass of the water disappeared.
Answer: B. The ice gained thermal energy and changed from a solid to a liquid.