Physical Science Unit Test

Ella makes this table to organize her notes on whether atoms gain or lose energy during the changes of state. Which changes of state should she place in the column titled "Lose Energy"?

freezing, deposition, and condensation

Which characteristic of a substance is considered a chemical property?

its reactivity

Which laboratory activity involves a chemical change?

leaving a copper penny in vinegar until it turns green

The atoms in a sample are close together but can slide past one another. As the atoms lose energy, they move slower. The atoms become locked in place because of attractive forces between them. Which change of state is taking place?

liquid to solid

Which of these are physical changes in matter? Check all that apply. boiling water a pencil being sharpened exploding dynamite freezing water rotting cheese

boiling water, a pencil being sharpened, freezing water

Which event always involves a chemical change?

burning

Hydrogen is very combustible in the presence of oxygen.

chemical

Hydrogen is very reactive with most elements.

chemical

Which statement summarizes the difference between mass and weight?

Mass is the amount of matter in an object, and weight is the downward pull on an object due to gravity.

Which object would sink in honey, which has a density of 1.4 g/cm³?

Object 4 (2.3 g/cm³)

In a science demonstration, a teacher mixed zinc (Zn) with hydrogen chloride (HCl) in a flask and quickly attached a balloon over the mouth of the flask. Bubbles formed in the solution and the balloon inflated. What most likely occurred during this demonstration?

One or more new substances formed.

Which statements describe chemical changes?

The after-rain smell is produced by an interaction between rain and the oils released by plants, A homemade volcano can be created by combining baking soda and vinegar. When it erupts, carbon dioxide gas is released, The Statue of Liberty has turned green over time due to the reaction of copper with carbon dioxide and water.

When hydrogen peroxide bubbles, it is undergoing a chemical change. Which statement best describes what is happening?

The atoms in hydrogen peroxide are breaking apart and forming new types of molecules.

Chanel has some cotton candy that came in a cloudy shape. She wants to make it more dense. Which describes the candy before and after Chanel manipulated it?

The candy before was fluffy, and the candy after was compacted.

An amount of nitrogen undergoes a physical change and increases its volume. What can be known about this physical change?

The density changed.

Which tools would Sara use to find an irregularly shaped object's mass and volume?

a balance, water, and a beaker

chemical change

a change in matter that results in a change in its identity and properties

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 observations most likely led to Jenna's conclusion?

a change of odor

chemical property

a characteristic of matter that describes its ability to change into a different substance

Which best describes what is made of matter?

all living things and objects

Which of these are chemical changes in matter? Check all that apply. mixing lemonade powder in water bleaching your hair mowing the lawn lighting a match letting fruit rot

bleaching your hair, lighting a match, letting fruit rot

In a science lab, Cash mixes two clear liquids together in a beaker. Bubbles are produced, and a white solid forms and settles to the bottom. He plans to heat the beaker over low heat and make more observations. Which statement is most likely correct?

A chemical change occurred, so even if Cash heats it, the white solid will remain.

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

A new substance forms when the batter is cooked.

Which of these is a chemical property of aluminum?

Aluminum is highly reactive.

How is energy related to the change of state represented by the model?

Atoms gain energy as a liquid changes to a gas.

Which statement best describes what happens during a chemical change?

Both the identity and the properties of a substance change.

You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring?

If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.

Investigations were carried out in a science lab to explore the topic of chemical and physical changes. Investigation A Step 1. Add 5 tsp. salt to 100 ml warm water and stir until most or all of the salt is no longer visible.Step 2. Heat the salt solution on a burner until only a white solid remains. Investigation B Step 1. Mix 10 tsp. white sugar into 100 ml water and stir until most or all of the sugar is no longer visible.Step 2. Heat the sugar solution on a burner until the solution thickens and turns brown. In which step(s) did a chemical change most likely occur?

Investigation B, Step 2 only

Uranium is a type of atom. In special circumstances that usually involve high amounts of energy, uranium can be broken. When this occurs, different pieces of the original atom remain, including a substance called plutonium. Which statement most likely describes plutonium?

It must be a different kind of atom.

What happens to the total mass of a substance undergoing a physical change?

It stays the same.

What causes leaves to change color in the autumn? Is the change physical or chemical? Explain your answer.

Leaf color comes from three pigments: chlorophyll, carotenoid, and anthocyanin. Chlorophyll is the pigment that makes leaves green and allows plants to make their own food using sunlight, water, and carbon dioxide. In the autumn, trees stop producing chlorophyll because there is less sunlight available. This allows carotenoid to show through, making the leaves yellow, orange, and brown. This is an example of a chemical change.

When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a chemical change. Explain your answer.

This is a chemical change because new substances are formed with different properties and identities.

Justin is making a snack. He toasts a piece of bread and spreads peanut butter and jelly on it. Then he cuts an apple into several slices and adds these to his plate. Next, Justin mixes a scoop of lemonade powder into a glass of water, mixes it, and adds ice. How many chemical changes occurred in this scenario?

one

Matter does not exist in which scenario?

parts of outer space where there is no air or atoms

Hydrogen is a colorless, tasteless, and odorless gas.

physical

Hydrogen is the least dense of all elements.

physical

During which changes of state do atoms that cannot move past one another become free to move?

sublimation and melting

combustibility

the ability of a substance to burn

reactivity

the ability of a substance to combine chemically with another

If a person has the values for an object's density and volume, what value can be calculated?

the object's mass