Chapter 2 Test:Chemical Reactions and Equations

Which situation involves a chemical change?

• food rotting

• paper ripping

• water freezing

Which statement proves that a chemical reaction has occurred?

• Bubbles form in a liquid

• At least one substance changes color

• Substances with new chemical properties are formed.

Which equation is balanced?

• H₂ +O₂--->H₂O

• 2Na + Cl₂ ---> 2NaCl

• CH₄ + 2O₂ ---> CO₂ + H₂O

Which situation does NOT occur during chemical reactions?

• Bonds are broken.

• Atoms are created.

• Compounds are formed.

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

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NGSS.MS-PS1-1

NGSS.MS-PS1-5

The reactants are on the left side of the chemical equation.

• True
• False

Tags

NGSS.MS-PS1-5

In a ___________change, a substance changes into a different substance.

• Physical

• Chemical

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

An gel ice pack getting cold after you put it in the freezer for an hour.

• Chemical change

• Physical change

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

What is the small number written after a chemical symbol called?

• Coefficient
• Subscript
• Product
• Reactant

Tags

NGSS.MS-PS1-1

According to the law of conservation of mass...

• sometimes atoms are lost

• sometimes atoms are gained

• atoms are not created nor destroyed

• atoms are lost and gained