physical change

reversing physical changes

When matter undergoes physical change, it doesnt become a different substance. Therefore, physical changes are often easy to reverse. For example, when liquid water freezes to form ice, it can be changed back to liquid water by heating and melting the ice. Q: Salt dissolving in water is a physical change. How could this change be reversed? A: The salt water could be boiled until the water evaporates, leaving behind the salt. Water vapor from the boiling water could be captured and cooled. The water vapor would condense and change back to liquid water.

what is a physical change

A physical change is a change in one or more physical properties of matter without any change in chemical properties. In other words, matter doesnt change into a different substance in a physical change. Examples of physical change include changes in the size or shape of matter. Changes of statefor example, from solid to liquid or from liquid to gasare also physical changes. Some of the processes that cause physical changes include cutting, bending, dissolving, freezing, boiling, and melting. Four examples of physical change are pictured in the Figure Click image to the left or use the URL below. URL: Q: In the Figure 1.1, what physical changes are occurring? A: The paper is being cut into smaller pieces, which is changing its size and shape. The ice cubes are turning into a puddle of liquid water because they are melting. This is a change of state. The tablet is disappearing in the glass of water because it is dissolving into particles that are too small to see. The lighthouse is becoming coated with ice as ocean spray freezes on its surface. This is another change of state.

textbook_image

instructional diagrams

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questions

some physical changes involve chemical reactions.

a. true

-->  b. false

a physical change can result in an entirely different substance.

a. true

-->  b. false

physical changes can be brought about by

a) cutting.

b) bending.

c) dissolving.

-->  d) all of the above

physical changes include changes in the state of matter.

-->  a. true

b. false

all of the following processes cause physical changes in matter except

-->  a) burning.

b) melting.

c) freezing.

d) boiling.

diagram questions

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