AnswersPhysical ScienceRate of Chemical Reactions

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Two substances did not react with each other as expected. What is the most likely reason?

A
It was frozen.
B
It was hit with a hammer.
C
It was placed in a salt solution.
D
It was heated.
3

Food can spoil very quickly. Which methods are used to minimize the reactions that allow bacteria and fungi to grow?

A
preservatives and low temperature
B
high temperature and preservatives
C
catalysts and high temperatures
D
low temperatures and catalysts
4

Three students are working with different substances to measure the chemical changes that occur. Chao is working with milk, Mia is working with carbon dioxide gas, and Ezra is working with rock. Which would best describe the way to treat each substance to get a faster reaction?

A
Chao should change the concentration, Mia should adjust the pressure, and Ezra should decrease the surface area.
B
Chao should change the temperature, Mia should adjust the pressure, and Ezra should increase the surface area.
C
Chao should change the concentration, Mia should adjust the temperature, and Ezra should increase the surface area.
D
Chao should change the temperature, Mia should adjust the concentration, and Ezra should decrease the surface area.
9

Which best describes activation energy?

A
the amount of energy absorbed in an endothermic reaction
B
the maximum amount of energy required to end a chemical reaction
C
the minimum amount of energy required to start a chemical reaction
D
the amount of energy released in an exothermic reaction
10

Why is reaching activation energy necessary?

A
Reactants require a minimum amount of energy to start to break a chemical bond.
B
Products must have the maximum amount of energy to start to break a chemical bond.
C
Products require a minimum amount of energy to start to break a chemical bond.
D
Reactants must have the maximum amount of energy to start to break a chemical bond.

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