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1.
Without _____ in cells, the reactions in living things would occur too slowly or require temperatures that are too high for cells to survive.

A.high concentrations of reactants

B. high concentrations of products

C. the presence of inhibitors

D. the presence of enzymes



2.
Which part of the fire triangle provides the activation energy needed to start a fire?

A. heat

B. flame

C. oxygen

D. fuel



3.
How is the rate of a chemical reaction related to temperature?

A. It is dependent upon the temperature.

B. It is independent of the temperature.

C. It is slowed by higher temperature.

D. It is unrelated to temperature

4.
What is a substance used to decrease the rate of a chemical reaction?

A. fuel

B. catalyst

C. inhibitor

D.enzyme


5.
When two liquids are mixed in an endothermic reaction, what always happens to the temperature of the solution?

A. It gets colder.

B. It cools off until it freezes.

C. It gets warmer.

D. It heats up until it boils.

6.
Why does baking bread require a constant input of heat from the oven?

A. It is a chemical reaction.

B. It is a physical reaction.

C. It is an endothermic reaction.

D. It is an exothermic reaction.


What is the best form of fire safety?

A. the fire department

B. an extinguisher

C. fire prevention

D. a water hose

.
An exothermic reaction _____.

A. does not require activation energy

B. releases less energy than it uses

C. takes more time than an endothermic reaction

D. releases more energy than it uses

What type of chemicals act as biological catalysts by speeding up reactions in living things?

A. enzymes

B. fuels

C. inhibitors

D. reactants



Which describe a rapid reaction between oxygen and a fuel?

A. activation

B. combustion

C. heat

D. decomposition


When you chew your food to break down the larger pieces into smaller particles, how are you helping to increase the rate of the chemical reactions in your body that breaks down your food?

A. By increasing the temperature.

B. By increasing the concentration.

C. By increasing the surface area.

D. By limiting the effects of inhibitors.


What is the purpose of the burning splint in a reaction?

A. to change the reaction from an endothermic to an exothermic reaction

B. to change the reaction from an exothermic to an endothermic reaction

C. to lower the activation energy

D. to provide activation energy


Which is an example of how to supply activation energy to begin a reaction?

A. Add an inhibitor.

B. Heat the reaction flask on a hot plate.

C. Add a catalyst.

D. Cool the reaction flask in an ice bath.


.
If a burning candle is covered by a large glass beaker, the flame will go out. How does the beaker affect the conditions described by the fire triangle?

A. It limits the fuel available to the flame.

B. It prevents more oxygen from reaching the flame once the existing oxygen is used up.

C. It limits the heat available for the flame to continue to burn under the glass beaker.

D. It removes oxygen from the flame.



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Respuesta :

Becky975
1. the presence of enzymes
2. fuel
3. dependent of temperature
4. inhibitor
5. warmer
6. chemical reaction
7. fire prevention
8. no activation energy
9. enzymes
10. heat
11. A
12. provide activation energy
13. add a catalyst
14. d removes oxygen

Answer:

1. D; 2. A; 3. A; 4. C; 5. A; 6. C; 7. C; 8. D; 9. A; 10. B; 11. C; 12. D; 13. B; 14.B

Explanation:

1. Without the presence of enzymes in cells, the reactions in living things would occur too slowly or require temperatures that are too high for cells to survive. Enzymes are catalysts in living organisms also called as bio catalysts. They speed up the reaction by lowering the activation energy.

2. Its heat which provides the activation energy needed to start the fire. The three main components of fire triangle are heat, fuel and oxygen.

3. Rate of chemical reaction depends upon temperature with maximum rate at optimum temperature, beyond the optimum temperature the enzyme might get denatured lowering the rate of reaction.

4. Inhibitors are the one which reduce the rate of chemical reaction. There are some which are competitive inhibitors of substrate and some which are non-competitive inhibitors (do not bind at active site as substrate).

5. When two liquids are mixed in an endothermic reaction, the temperature of the solution gets colder. Endothermic reaction needs energy for the reaction to occur where as exothermic reaction liberates out energy during the chemical reaction.

6. In any reaction requires any outside source of energy such as heat then it is called endothermic reaction.

7. The best form of fire safety is fire prevention.

8. If the amount of energy released is more than the energy utilized in the reaction then it is called exothermic reaction.

9. Enzymes are also called as bio catalyst. They speed up the reaction living organisms.

10. The reaction between oxygen and a fuel is called combustion reaction.

11. When larger pieces are broken down into smaller pieces then the surface area increases for the action of digestive enzymes upon them.

12. The purpose of the burning splint in a reaction is to provide activation energy

13. Heating the reaction flask will provide the activation energy to begin a reaction.

14. Oxygen supports the burning of candle so if the candle is covered by a beaker the flame will go out once all the oxygen inside is used up.