Chemistry Chemical Reactions Review

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.

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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-PS1-5

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?

• 
• 
• 
• 

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NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student placed a liquid in a jar and sealed it. Then she heated the liquid and it turned into a gas. If the number of atom in the sealed jar stayed the same, what happened to the mass of the jar and everything inside it after she heated it?

• The mass increased (went up).

• The mass decreased (went down).

• The mass stayed the same.

• It depends on whether a chemical reaction occurred.

Tags

NGSS.MS-PS1-5

What will happen to the total mass of the jar and everything inside it after the plant dies?

• It depends on the type of plant.

• The mass will increase.

• The mass will decrease.

• The mass will stay the same.

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NGSS.MS-LS2-3

NGSS.MS-PS1-5

When a new substance forms as a result of a chemical reaction, what type of change has occurred?

• Chemical Change

• Physical Change

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NGSS.MS-PS1-2

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What is the left part of a chemical equation called?

2H_{2 +} O₂ --> 2H₂O

• Reactants

• Yields

• Products

• Chemical Equation

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NGSS.MS-PS1-1

In a chemical reaction, no new atoms are created, and no atoms are destroyed.

• TRUE

• FALSE

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

In a chemical equation, is it true that -

• the reactant side and product side can have different numbers of atoms for each element

• there can be different elements on the reactant side and the product side

• an element or compound must be accompanied by a phase change

• the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

Tags

NGSS.MS-PS1-5

Which of the following models best demonstrates a balanced chemical equation?

• F

• G

• H

• J

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NGSS.MS-PS1-2

NGSS.MS-PS1-5