Unit 4- Changes in Matter 8th Grade Review-2024

When a physical or chemical change occurs, the Law of Conservation of Mass always applies. What happens to matter during a chemical change according to this law?

• matter is created

• matter is destroyed

• matter is transformed

• matter is changed into charged particles

Tags

NGSS.MS-PS1-5

Which of the following best demonstrates a chemical change?

• Bending a steel bar

• Splitting a wooden board into two pieces

• Baking cookies

• Slicing carrots

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

When sugar is added to water to make a solution, a physical change occurs. According to the Law of Conservation of Mass, what prediction can be made about this physical change?

• The sugar solution will have the same mass as the sugar and water.

• The sugar solution will have less mass than the sugar and water.

• The sugar solution will have more mass than the sugar and water.

• The sugar solution will have the same volume as the water in the beaker.

Tags

NGSS.MS-PS1-2

It is not always clear when a substance undergoes a chemical change. Which of the following is most likely evidence of a chemical change?

• A substance gets smaller.

• A substance gives off heat.

• A substance can go back to the way it was before the change.

• A substance changes state.

Tags

NGSS.MS-PS1-2

Temperature influences chemical reactions. Glow sticks use chemical reactions to produce light. One kind of glow stick produces light for about 4 hours on a summer night. What will most likely happen to this kind of glow stick when one is used on a very cold winter night?

• It will not change.

• It will be brighter and last longer.

• It will be dimmer and not last very long.

• It will be dimmer and last longer.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Steve fills a jar with water and adds Epsom salts and ammonia. After five minutes, he observes that white particles have formed and settled at the bottom of the jar. Steve is unable to change these particles back to any of the three original substances by heating or stirring the solution. He isolates the white particles and finds that they have properties that are very different from any of the three starting materials. Which statement best explains Steve's observation?

• A chemical change occurred because a solid substance formed.

• A chemical change occurred because a new substance formed.

• A physical change occurred because no color change was observed.

• A physical change occurred because stirring did not change the solution.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Chemical changes are influenced by temperature. Which one of the following statements about temperature and chemical changes is correct?

• Reactions happen slower when it is cold.

• Reactions happen faster when it is cold.

• Reactions can only happen when it is hot.

• Reactions can be controlled more when it is hot.

Tags

NGSS.MS-PS1-4

A mass of 200 grams (g) of solid iron is heated at a high temperature until the iron has completely melted. What is the mass of the liquid iron after heating?

• 100g

• 150g

• 200g

• 250g

Tags

NGSS.MS-PS1-4

Temperature plays a significant role in influencing chemical reactions. Which of the following statements regarding the effect of temperature on chemical processes is accurate?

• All metals exist at low temperatures.

• All chemical reactions occur spontaneously at room temperature.

• The freezing point of all substances is below room temperature.

• A beaker containing hot acid will cause a metal to corrode more rapidly than a beaker containing cold acid.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

In art class, Paula created a figure of a dog using modeling clay. Which of the following occurred when Paula created the clay figure?

• She had less clay to work with so she made a smaller clay figure.

• She changed the chemical properties of the clay.

• She physically changed the clay.

• She created new atoms in the clay.