Answers GA-GSE Grade 8 Physical ScienceUnit Test

Unit Test — Unit test Answers

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A substance occupies one half of an open container. The atoms of the substance are closely packed but are still able to slide past each other.What is most likely the phase of the substance?

gas

liquid

solid and gas

liquid and solid

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What is the density of a 700 kg object with a volume of 649 m3? (Density: D = )

0.927 kg/m3

.4543 kg/m3

1.079 kg/m3

4.543 kg/m3

Which is most likely a physical change?

cutting a substance into four pieces

burning a substance into ash and smoke

reacting a substance chemically to form a new substance

combining a substance with water to make rust

If two items are equal in size, the denser one will

be lighter.

be heavier.

have more volume.

have less volume.

The descriptions below explain two ways that water is used by plants on a sunny day.I. In a process called transpiration, some liquid water in leaves changes to water vapor. The water vapor is released into the air through tiny pores in the leaves. This allows more liquid water from the soil to be pulled up the roots and stem to replace water lost from the leaves.II. Plants use some of this water in leaves in a process called photosynthesis. During photosynthesis, water and carbon dioxide break apart and recombine to form two new substances, oxygen and glucose.

In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change.

In transpiration, because some of its properties change, water undergoes a chemical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a physical change.

In transpiration, because its physical properties change, water undergoes a physical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a chemical change.

In transpiration, because its chemical properties change, water undergoes a chemical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a physical change.

During which change of state do atoms lose energy?

sublimation

freezing

boiling

melting

Rahul sees a flock of birds. He watches as the flying birds land in neat little rows on several power lines. Which change of state does the motion of the birds most closely model?

melting

vaporization

deposition

sublimation

Three grams of the same substance in different phases are stored in three different containers. Each container is barely large enough to hold the substance.Which statement can be known about the behavior of the atoms in each container?

The atoms in the solid would be moving vigorously around the container.

The atoms in the liquid would be vibrating in position.

The atoms in the solid would be vibrating in position.

The atoms in the gas would be moving slowly around the container.

The density of solid aluminum is 2.70 g/cm3. If a 1g piece of aluminum is dropped in a cup of water, what will happen to the aluminum? (The density of water is 1.00 g/cm3.)

It will sink to the bottom.

It will float to the top.

It will hover in the middle.

It will move up and down.

Tijuan mixed a solid and a liquid together in a beaker. He determined that a chemical change occurred.

ice mixed into warm oil, because the change of state that occurred when the ice melted cannot be reversed

baking soda mixed into vinegar, because the production of bubbles indicates that a new substance formed

sugar mixed into hot water, because the disappearance of solid indicates that the chemical identity of the sugar changed

sand mixed into water, because when sand was added the mass of the beaker increased

Suppose that a substance in a beaker is heated over a burner in a science lab. Which observation would most likely indicate that a chemical change has occurred in the substance?

If the substance is a liquid or solid, an increase in temperature would indicate a chemical change.

If the substance is a liquid, a change of some of the liquid to gaseous form would indicate a chemical change.

If the substance is a solid, a change of some of the solid to liquid form would indicate a chemical change.

If the substance is a liquid or solid, production of an odor would indicate a chemical change.

Which would show an example of how physical changes are reversible?

cutting a gold bar in two pieces and then putting the pieces next to each other

burning a match and then relighting it

melting tin and then cooling it into a mold

combining sodium and chlorine to make the new material of table salt

Which is the process by which a gas changes to a solid?

deposition

evaporation

freezing

sublimation

Sari is studying four different samples of materials. This table shows the mass and volume of the samples.

W and Y

X, W, and Y

A column is filled with four different liquids of different densities. A red liquid, a blue liquid, a green liquid, and a purple liquid are all added into the column. This chart shows the densities of the liquids.In what order would the liquids arrange themselves, from top to bottom?

blue, red, purple, green.

purple, green, red, blue.

purple, green, blue, red.

blue, red, green, purple.

The density of an object is .835 g/cm3. If its volume is 34 cm3, what is the mass of the object? (Density: D = )

.02 g

.41 g

28.39 g

40.72 g

The diagram shows changes of state between solid, liquid, and gas. The atoms of a substance gain energy during a change of state. Before the change, the atoms are close together and cannot slide past one another. After the change, the substance can fill its container.

Venn diagrams are used for comparing and contrasting different topics. The overlapping sections show characteristics that the topics have in common, and the sections that are unique to each topic show the characteristics apply to only that topic.

Overlapping circles are labeled definite shape most dense at top, mid-level density at right, definite volume least dense at left, with the intersection labeled state of matter.

Overlapping circles are labeled definite shape most dense at top, mid-level density at right, least dense at left, with the intersection of all three labeled state of matter. The intersection of the top and right circles is labeled definite volume.

Overlapping circles are labeled definite shape most dense at top, definite volume mid-level density at right, least dense at left, with the intersection of all three labeled state of matter. The intersection of the left and right circles is labeled definite shape.

Overlapping circles are labeled definite shape least dense at top, definite mid-level density at right, most dense at left, with the intersection of all three labeled state of matter. The intersection of the left and right circles is labeled definite shape.

Which procedure would best allow a scientist to observe a chemical property of hydrochloric acid (HCl) solution?

cooling the HCl solution until it becomes solid, and measuring this temperature

adding zinc to the HCl solution and observing whether or not bubbles are produced

placing a conductivity probe into a beaker of HCl solution to determine if it conducts electricity

measuring the mass of and volume of a sample of HCl solution to find its density

Which describes a feature of the physical changes of all substances?

can dissolve in water

can conduct heat and electricity

rearranges atoms to form new substances

does not change the identity of a substance

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