Changes in States of Matter

TEKS Review Name ______Date ______3.5C

TEKS 3.5C predict, observe, and record changes in the state of matter caused by heating or cooling

What Is Matter? Aluminum is a solid at room temperature. A solid is the state of Anything that has mass and takes up space matter that holds its own shape and is matter. All physical objects are made of has a fixed volume. You can bend matter. If you could view an object through the and tear a sheet of aluminum foil, most powerful microscope, you would see that but the total volume of aluminum does matter is made of tiny particles called atoms. not change. Different types of matter are made of different arrangements of atoms. Each type of matter has Solids keep their shapes. Liquids flow. physical properties that you can see, smell, Gases fill their containers. Why? You can touch, taste, measure, and study. answer this question by thinking of matter as being made of tiny particles that are in motion. States of Matter The state of matter is dependent upon the amount of energy the matter contains. You know that different kinds of matter The particles in a solid are packed very have different properties. Helium, water, and close together. They vibrate in place, but they aluminum, for example, are very easy to tell can’t slide past one another. This gives a solid apart. At room temperature, each of these kinds its definite volume and shape. of matter exists in a different state. One is a solid, one is a liquid, and one is a gas. Do you The particles in a liquid are not as close know which is which? together. They have more energy and can move past one another. This enables a liquid to flow. At room temperature, helium is a gas. A gas is the state of matter The particles in a gas have a lot of energy. that expands to fill its container. They are not very close together and move the A gas does not have a definite shape fastest. They spread out to fill their container. or volume. Helium gas is used to The particles are so far apart that they can be fill balloons. squeezed together. That’s what you do when

you pump up a ball or a tire. You squeeze more Water is a liquid at room temperature. A gas into the ball or tire, which gives it pressure. liquid is the state of matter that has a fixed volume but not a definite shape.

A liquid takes the shape of its container. You can pour liquid water from a pitcher to a glass. solid liquid gas

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Changes in Matter Let’s take a closer look at water. Water is a liquid at room temperature. If you put it in a Matter can go through physical and freezer, its temperature chemical changes. A physical change does not decreases. The particles of change what a substance is. When paper is cut, water begin to slow down. shredded, or torn, it is still paper. This is a At temperatures below physical change. A chemical change results in a 0°C (32°F), water freezes. new substance being formed, and energy is Freezing is the change from either given off or absorbed. When paper is a liquid to a solid. Solid water burned, it turns new forms of matter—hot gases is called ice. and ash. If you remove an ice cube from the freezer, Changes in State it slowly warms. The particles of water begin to move faster and slide past one another. At You learned that some kinds of matter are temperatures above 0°C, ice melts. Melting is solid at room temperature. Other kinds of matter the change from a solid to a liquid. are liquid or gas at room temperature. Did you know that each kind of matter can exist as a solid, a liquid, or a gas? Ice is solid water. It melts The temperature of matter determines its and becomes liquid water. state. As heat is added, the particles of matter begin to move faster. As heat is taken away, the particles move slower. When enough heat is added or taken away, matter can change state. Place a pot of liquid water on a hot stove, For example, aluminum foil will turn into a and the water gets warmer. When it reaches liquid if its temperature reaches 660°C 100°C (212°F), it boils. Boiling is the rapid (1,220°F). It is still aluminum, but it is no change from a liquid to a gas. Sometimes, longer a solid. This is a change in state. Changes particles near the surface of a liquid move fast in state are physical changes. enough to become a gas, even if the temperature is not at the boiling point. This is called evaporation, which occurs slowly and only at the surface of a liquid.

To form a seal between two metal pipes, The boiling a welder heats metal so it turns into a point of water liquid that can be formed into a certain is 100°C. shape. TEKS Review and Assessment TEKS 3.5C Page 2 of 6 © Houghton Mifflin Harcourt Publishing Company TEKS Review Name ______Date ______3.5C

When a gas turns to a liquid, the process is called condensation. You have seen this process occur when water drops form on the Condensation is the process of outside of a cold glass. It might look like the turning a gas into a glass is leaking, but that’s not the case. Water in liquid. We also call the form of a gas is called water vapor. It’s in the physical drops the air all around you, but you can’t see it. The of liquid that form water vapor’s temperature is cooled by the cold condensation . glass. The decrease in temperature causes the water vapor to condense and form droplets of liquid water.

Hands-On Activity

Observing States of Matter Materials The state of matter can change based on the amount of energy in • ice cubes the substance. Matter can exist as a solid, a liquid, or a gas. In this • water activity, you will examine water in each of these states. • hot plate

• freezer-strength zip-top bags Procedure:

1. Place a few ice cubes in a zip-top bag. Pass the bag around. Squeeze and press the bag. What happens? In a small group, discuss the properties of the ice. Include temperature, texture, shape, and color in your discussion.

2. Pour some water into a zip-top bag, and seal it. Pass the bag around. Gently squeeze and press the bag. What happens? Discuss the properties of the water. Include temperature, texture, shape, and color in your discussion.

3. Watch as your teacher holds a zip-top bag over boiling water to capture some water vapor. The water vapor is mixing with the air around you. Pass the sealed bag around the classroom. Gently squeeze and press the bag. What happens? Discuss the properties of the water vapor and other gases in the bag. Include temperature, shape, and color in your discussion.

Discussion Questions:

1. What differences did you notice in the different states of water?

2. What are other examples of solids, liquids, and gases?

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Changes in States of Matter

Write a definition for each term below.

______freeze ______boil ______condense ______

Suppose an ice cube is taken out of the freezer. Predict how it will change over several hours.

______

Complete the cause-and-effect graphic organizer below.

Cause Effect

The liquid evaporates.

Complete the Venn diagram below to compare and contrast melting and boiling.

Melting

Both Boiling

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TEKS Assessment 3.5C

Fill in the letter of the best choice.

Which is the process by which a gas Which of the following is correct? becomes a liquid? Only water can exist as a solid, a evaporation liquid, and a gas. condensation The solid form of water is called melting water vapor. A change of state is a chemical boiling change because a new kind of What happens to the particles of matter matter is formed. when a liquid changes to a gas? At the right temperature, any kind of matter can exist as a solid, a They stop moving. liquid, or a gas. They vibrate in place. They move faster and spread out. Look at the thermometer below. They slow down and begin bumping into one another.

Look at the drawing below.

Which prediction is correct? What properties does water have at this temperature? The ice will melt, and condensation will form on outside of the glass. It would fill its container. The ice will evaporate before it It would hold its own shape. finishes melting. It would not have a shape. The ice will boil, and water will It would take the shape of its spill on the outside of the glass. container. The ice will condense and stick to the outside of the glass.

TEKS Review and Assessment TEKS 3.5C Page 5 of 6 © Houghton Mifflin Harcourt Publishing Company TEKS Review Name ______Date ______3.5C

Answer Key

Hands-On Activity (p. 3)

1. Students should note that the ice (solid water) had a definite shape, was hard, and was cold. The liquid water was not cold, changed shape when the shape of the bag was changed, and did not fill the bag completely. The water vapor filled the entire space inside the bag. It was not possible to see the water vapor.

2. Answers will vary. Sample answers: Helium in a balloon, the air we breathe, propane in a stove, and natural gas that heats a home are examples of gases. Examples of liquids include honey, vinegar, soda, juice, and gasoline. Most of the objects used in the classroom are solids, including desks, books, pencils, paper, and backpacks.

Student Response Activity (p. 4)

1. To freeze is to change from a liquid to a solid. To boil is to turn rapidly from a liquid to a gas. To condense is to change from a gas to a liquid.

2. When an ice cube is taken out of the freezer, heat energy will move into the ice cube and the ice cube will begin to get warmer. As the temperature gets above 0°C (32°F), the ice will melt. Liquid water on the surface may evaporate, or turn in to a gas. The puddle of water formed will eventually dry up if given enough time to evaporate completely.

3. The particles on the surface of a liquid get enough energy and move fast enough to escape from the other liquid particles.

4. Melting—changing from a solid to a liquid; Boiling—changing from a liquid to a gas; Both—changes in state, require addition of energy

TEKS Assessment (p. 5)

1. B

2. C

3. A

4. D

5. D