Unit Test Answers

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.

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

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.

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

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

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.

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

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?

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

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

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?

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?

Which is most likely a physical change?

During which change of state do atoms lose energy?

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.)

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?

Which statement best describes the energy changes associated with evaporation and boiling?

Which statement best describes the atoms in a solid?

Liquid plastic is frozen in a physical change that increases its volume. What can be known about the plastic after the change?

Which statement best describes the atoms in a gas?

A cylinder at left with balls evenly spaced throughout the cylinder with an arrow leading to a cylinder at right with balls stacked near the bottom of the cylinder.

What happens during evaporation?

Which best explains why making a pancake from batter is an example of a chemical change?

Jenna took an open bowl of leftover mashed potatoes from the refrigerator and noticed a difference in smell. She determined that chemical changes occurred since the potatoes were first placed there.

Which liquid is the most viscous?