AnswersFL-2003010-MJ Physical ScienceChanges of State

Chemical Properties Answers

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Investigations were carried out in a science lab to explore the topic of chemical and physical changes.Investigation AStep 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 BStep 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.

A
Investigation A, Step 1 and Investigation B, Step 1
B
Investigation A, Step 2 and Investigation B, Step 2
C
Investigation A, Step 2 only
D
Investigation B, Step 2 only
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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.

A
a change of odor
B
a decrease in temperature
C
a change in moisture content
D
a decrease in mass
3

Which statement best describes chemical properties of matter?

A
Chemical properties, such as density, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure.
B
Chemical properties, such as reactivity, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure.
C
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.
D
Chemical properties, such as boiling point, are generally observed as the identity of a substance changes and one or more new substances form.
4

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.

A
one
B
two
C
three
D
four
5

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.

A
A physical change occurred, so if Cash heats it, the white solid will dissolve to form the original mixture of clear liquids.
B
A physical change occurred, so even if Cash heats it, the white solid will remain.
C
A chemical change occurred, so if Cash heats it, the white solid will dissolve to form the original mixture of clear liquids.
D
A chemical change occurred, so even if Cash heats it, the white solid will remain.
6

A scientist is examining an unknown solid. Which procedure would most likely help determine a chemical property of the substance?

A
heating it to find the temperature at which it melts
B
exposing it to a flame to see if it catches on fire
C
hitting it with a hammer to determine if it breaks or bends
D
placing it in water to find out whether or not it dissolves
7

Which laboratory activity involves a chemical change?

A
leaving a copper penny in vinegar until it turns green
B
boiling saltwater for several minutes until only solid salt remains
C
extracting iron filings from a sand mixture using a magnet
D
crushing a rock with a hammer to extract mineral deposits
8

Which statement best describes a physical change?

A
Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the same.
B
Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the same.
C
Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
D
Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.
9

What is the outcome of all chemical changes when two substances are combined?

A
A new substance forms with identical properties.
B
The two substances release an odor.
C
The two substances change color.
D
A new substance forms with different properties.
10

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

A
The pancake that forms is a different state of matter.
B
The change from batter to pancake can be reversed.
C
A new substance forms when the batter is cooked.
D
The batter changes shape when it is cooked.
11

Which statement best describes what happens during a chemical change?

A
Both the identity and the properties of a substance change.
B
Some properties of a substance change, but its identity remains the same.
C
The chemical properties of a substance change, but its physical properties remain the same.
D
The physical properties of a substance change, but its chemical properties remain the same.
12

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.

A
The Zn and HCl both retained their identity.
B
Either Zn or HCl, but not both, retained its identity.
C
Evaporation of one of the substances occurred.
D
One or more new substances formed.
13

Henry mixed salt and water together in a cup until he observed a clear solution. He measured the mass of the solution. Then he placed the cup outside for several sunny days during the summer. After a week, he observed that only solid salt remained in the cup and the mass had decreased. Henry concluded that a physical and chemical change occurred in this investigation.

A
He is correct. Dissolving salt in water is a physical change, but evaporating the water is a chemical change. Formation of a solid is evidence that a chemical change occurred.
B
He is correct. Evaporation is a physical change, but dissolving salt in water is a chemical change. The change in mass is evidence that a chemical change occurred.
C
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
D
He is incorrect. Dissolving salt in water and evaporation of the water are both chemical changes. The reappearance of salt is evidence that the change was reversible by a chemical change, so it could not be a physical change.
14

Which event always involves a chemical change?

A
boiling
B
melting
C
conducting
D
burning
15

Which statement describes all chemical changes, but not all physical changes?

A
Bubbles are produced.
B
A new substance forms.
C
Phase changes occur.
D
A color change occurs.
16

Which characteristic of a substance is considered a chemical property?

A
its boiling point
B
its reactivity
C
its density
D
its conductivity

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