Chem – Chapter 5: Energetics

1

What is the main product of anaerobic respiration in yeast?

A Carbon dioxide and water B Lactic acid C Ethanol and carbon dioxide D Glucose and oxygen

2

Which of the following is an endothermic process?

A Burning of wood B Melting of ice C Respiration D Rusting of iron

3

In an endothermic reaction, heat is:

A Released to the surroundings B Absorbed from the surroundings C Neither absorbed nor released D Converted into mass

4

In an open system, what can be exchanged with the surroundings?

A Only energy B Only matter C Both matter and energy D Neither matter nor energy

5

Which of the following is the first step of both aerobic and anaerobic respiration?

A Krebs cycle B Electron transport chain C Glycolysis D Fermentation

6

What is enthalpy?

A The heat content of a system at constant pressure B The total mass of a system C The volume of a gas D The temperature of surroundings

7

In an energy level diagram, an exothermic reaction shows products at:

A Higher energy than reactants B Lower energy than reactants C Same energy as reactants D Zero energy

8

In an isolated system, which quantity remains constant?

A Mass B Energy C Volume D Pressure

9

According to collision theory, what is necessary for a reaction to occur?

A Particles must collide with energy equal to or greater than the activation energy B Particles must collide with low energy C Particles must always be in the same state D Particles must never collide

10

Which of the following is a closed system?

A A system that can exchange both matter and energy with its surroundings B A system that can exchange energy but not matter with its surroundings C A system that cannot exchange either matter or energy with its surroundings D A system that can exchange matter but not energy with its surroundings

11

Which of the following is an exothermic process?

A Melting of ice B Boiling of water C Burning of methane D Photosynthesis

12

The enthalpy change (ΔH) of a reaction is measured using a:

A Thermometer B Calorimeter C Barometer D Hydrometer

13

In a closed system, which of the following can be exchanged with the surroundings?

A Only matter B Only energy C Both matter and energy D Neither matter nor energy

14

Which type of system allows energy exchange but not matter exchange?

A Open system B Closed system C Isolated system D Reversible system

15

Which factor increases the rate of reaction by increasing collision frequency?

A Decreasing surface area B Increasing temperature C Adding a catalyst D Decreasing concentration

16

In an energy level diagram for an exothermic reaction, the reactants are at:

A Lower energy than products B Higher energy than products C Same energy as products D At zero energy

17

What is formed at the transition state of a reaction?

A Activated complex B Product C Catalyst D Reactant

18

What is the first stage of respiration that breaks down glucose into pyruvate?

A Glycolysis B Krebs cycle C Electron transport chain D Fermentation

19

For an exothermic reaction, the sign of ΔH is:

A Positive B Negative C Zero D Depends on temperature

20

In an exothermic reaction, the sign of ΔH is:

A Positive B Negative C Zero D Depends on the reaction

21

According to collision theory, a reaction occurs when reactant molecules collide with sufficient energy and proper ____.

A orientation B mass C volume D density

22

During glycolysis, one molecule of glucose is converted into:

A Two molecules of pyruvate B One molecule of pyruvate C Two molecules of ethanol D Two molecules of lactic acid

23

If a reaction has ΔH = +50 kJ/mol, the reaction is:

A Exothermic B Endothermic C Neither exothermic nor endothermic D Both exothermic and endothermic

24

Glycolysis is the breakdown of:

A Glucose into pyruvate B Pyruvate into glucose C Fat into glucose D Protein into amino acids

25

Which factor does NOT generally affect the rate of a chemical reaction?

A Concentration of reactants B Temperature C Surface area D Colour of the container