Unit Test — Unit test Answers

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 would show an example of how physical changes are reversible?

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

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?

This chart show the amount of radioactivity measured from three unknown isotopes.Which statement describes each of the isotopes?

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

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?

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

Which best describes a radioactive isotope?

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 argument best explains the charge of an atomic nucleus?

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?

A blue circle labeled proton and A overlaps a pink circle labeled electron and C. The overlap is labeled B.

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

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 most likely a physical change?

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

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