Chemical Reactions Review

A chemical reaction is taking place in a sealed container. What will happen to the mass of the materials in this sealed (closed) container?

• It will depend on which chemical reaction occurs.

• The mass will stay the same.

• The mass will increase.

• The mass will decrease.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student places some baking soda and a jar of lemon juice in a plastic bag and seals the bag. She weighs the bag and everything in it. She shakes the bag so that the lemon juice spills out of the jar and mixes with the baking soda inside the bag. The student observes that bubbles form and the bag expands.

If the student weighs the bag and everything in it after the bubbling stops and compares the final weight to the starting weight, what will she find out?

• The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment.

• The final weight will be greater than the starting weight because new atoms are produced during the experiment.

• The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment.

• The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following statements about chemical reactions is TRUE?

• Chemical reactions occur between liquids but not between gases or solids.

• Chemicals reactions occur between solids and liquids but not between solids and gases.

• Chemical reactions produce solids, liquids and gases.

• Chemical reactions produce solids and gases but not liquids.

Tags

NGSS.MS-PS1-5

A student has a ball of wax. The wax is a pure substance. The student removes a small piece of wax from the ball. Which of the following statements is TRUE about what happens to the mass and melting point of the ball of wax after the piece is removed.

• Both the mass and melting point of the ball of wax change.

• The melting point of the ball of wax changes, and its mass stays the same.

• Both the mass and the melting point of the ball of wax stay the same.

• The mass of the ball of wax changes, and its melting point stays the same.

A thermometer is heated. The volume of the liquid inside of the thermometer increases (goes up), and the level of the liquid rises.

What happens to the MASS of the liquid in the thermometer as the level of liquid rises?

• The mass stays the same.

• The mass increases.

• It depends on the type of liquid.

• The mass decreases.

Tags

NGSS.MS-PS1-5

A student mixes two different liquids together. After mixing the liquids, a solid substance forms (precipitate) that cannot be turned back into the starting liquid. The student claims that a chemical reaction occurred. Why is the student correct?

• Because the products of a chemical reaction can never be turned back into the starting substance.

• Because a solid substance is always formed during a chemical reaction.

• Because a chemical reactions always occurs when two substances are mixed together.

• Because a new substance is always formed during a chemical reaction.

Tags

NGSS.MS-PS1-2

Atoms are represented by circles, and molecules are represented by circles that are connected to each other. The different colored circles represent different kinds of atoms.

Which of the following could represent a chemical reaction?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is an example of a chemical reaction?

• A powder dissolving in hot water to make hot chocolate.

• A piece of chalk for making white marks on a chalkboard.

• Bubbles of gas forming a seashell is placed in vinegar.

• A piece of wax melting and forming a liquid.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student adds water and sugar to a jar and seals the jar so that nothing can get in or out. THe student then weighs the jar containing the water ans sugar. After some sugar dissolves, the student weighs the jar and its contents again.

What will happen to the weight of the jar containing the water and sugar after some of the sugar dissolves?

• The weight will stay the same.

• The weight will increase.

• The weight will decrease.

• The weight will depend on how much sugar dissolves.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is an example of a chemical reaction?

• Aluminum foil being cut into smaller pieces.

• Melted butter becoming a solid when placed in the refrigerator.

• The surface of a copper penny changing color after being in a drawer for years.

• A drop of food coloring dissolving in water.

Tags

NGSS.MS-PS1-2