Big Idea 9 Changes in Matter

Annie has a jar she has filled with milk. How can she change the state of this liquid?

• Separate the milk into three smaller jars

• Mix the milk with powdered chocolate

• Add food coloring to the milk

• A)Put the jar in the freezer

When Bobby and his parents first moved into their house, the brick fireplace was very clean. Now that they have built a few fires in their fireplace, the inside is covered with black powder. Bobby’s mother tells him that this powder is called soot. Which of the following best explains how the soot came to be in the fireplace?

• A chemical reaction occurred between the bricks and air, making a new substance called soot.

• A chemical reaction occurred when wood burned, making a new substance called soot

• Some of the bricks in the fireplace melted and made a new substance called soot.

• The wood in the fireplace evaporated and made a new substance called soot.

Ling is learning about chemical reactions in Science class. She measured out 45 grams of vinegar and 10 grams of baking soda. When she mixes them together, a bubbling reaction occurs. After the reaction has stopped, she weighs the mixture and finds that it weighs 54 grams. Which of the following best explains why the mixture now weighs less than the original ingredients?

• Some of the vinegar evaporated during the experiment.

• The chemical reaction created a gas that left the mixture.

• The new solution is less dense than vinegar or baking soda.

• The baking soda is floating on top of the vinegar.

Adam spilled some water on a metal picnic table. When he came back to the table, he noticed the water was no longer there. If nobody wiped up the water, what can Adam conclude happened to it?

• The water was absorbed by the table.

• The water separated into different elements: hydrogen and oxygen.

• The water evaporated

• The water chemically reacted with the table.

Richard goes to his bus stop the morning after a heavy rain. When he gets to the bus stop at 8 a.m., the Sun is shining on puddles that formed on the sidewalk. When he is dropped off at the bus stop at 3 p.m., the Sun is still shining, but the puddles are gone. What happened to the water?

• It melted

• It froze

• It condensed

• It evaporated

Which action changes a liquid into a solid form?

• boiling

• melting

• freezing

• condensing

Marlon fills an ice cube tray with water and puts it into the freezer. Which of the following statements describes what will happen as the water freezes?

• Its mass will change

• Its state will change

• Its density will increase

• Its temperature will increase

Duane left his bicycle outside in the rain for several days. He notices some spots on the bicycle’s iron frame have changed color from silvery-gray to reddish-orange. These spots are also rough to the touch. The rest of the frame is smooth. Which statement best describes what has happened?

• The water coated the iron and cooled to form a reddish-orange solution called rust.

• The water eroded the outer layer of the iron to expose the rust underneath.

• The water cooled the iron, which caused it to become rust.

• The water chemically reacted with the iron to form a new compound called rust.

Debbie is learning about weather. She wonders how temperature affects the rate of evaporation. She conducts an experiment to find out by placing equal amounts of water in identical dishes. She places one dish near a sunny window and the other on a table in a windowless, air-conditioned room. In three days, she returns to check the dishes. What will she find?

• The two dishes contain the same amount of water.

• The dish near the window contains less water than the dish in the windowless room.

• Both dishes contain more water than they did three days ago.

• The water in the dish in the windowless room has completely evaporated

When water is heated to 100 degrees Celsius, it begins to boil. Some of the water begins to escape as steam. Which best describes what has happened to the water? SELECT THE BEST TWO ANSWERS

• Its mass has changed

• Its density increased

• Its state changed

• Its temperature changed