Changes of State — Unit test Answers

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

Who is known as the "father of modern chemistry” because he first organized all known elements into four different groups?

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

This is how sodium appears in the periodic table.

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

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.

An atom of the element zinc has an atomic number of 30 and a mass number of 65. How many protons does an uncharged zinc atom have?

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

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

When an atom that has no charge loses two electrons, it becomes a

During which change of state do atoms lose energy?

The elements in group 17 of the periodic table are all called halogens. All halogens have the same

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?

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.

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.)

Which is most likely a physical change?

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?

Atom A and Atom B have the same number of protons, but they do not have the same number of neutrons.Which statement describes these atoms?

While looking at xenon (Xe) on the periodic table, a student needs to find an element with a smaller atomic mass in the same group. Where should the student look?

Scientists in a lab are working with two different samples of the element mercury. They know that the different samples are different isotopes.