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C5 Energy Changes

Last updated 25 days ago

33 questions

4.5.1.1 Energy transfer during exothermic and endothermic reactions

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4.5.1.2 Reaction profiles

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4.5.1.3 The energy change of reactions

4.5.2.1 Cells and batteries

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4.5.2.2 Fuel cells

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Question 1

1.

What happens to energy in an endothermic reaction?

Energy stays the same throughout the reaction.

Energy is released into the surroundings.

Energy transforms into a different type.

Energy is absorbed from the surroundings.

Question 2

2.

In an endothermic reaction, how does the temperature change?

The reaction has no temperature change.

The temperature s increases.

The temperature decreases.

Question 3

3.

Question 4

4.

What do exothermic reactions release during the reaction?

Energy in the form of heat

Solid products only

Energy in the form of light

Electricity for powering devices

Question 5

5.

In an exothermic reaction, how does the temperature change?

Temperature remains the same

The temperature increases.

The temperature decreases

Question 6

6.

Question 7

7.

A reaction where the surrounding temperature decreases. Is this an exo or endothermic reaction?

Neither

Both

Endothermic reaction

Exothermic reaction

Question 8

8.

An ice cube is melting on a warm day. Is this an exo or endothermic reaction?

Both

Neither

Exothermic reaction

Endothermic reaction

Question 9

9.

You feel heat when adding water to a chemical heat pack. Is this an exo or endothermic reaction?

Both

Exothermic reaction

Neither

Endothermic reaction

Question 10

10.

A chemical reaction that increases the outside temperature. Is it an exo or an endothermic reaction?

Both

Endothermic reaction

Neither

Exothermic reaction

Question 11

11.

A student investigated the reactivity of metals with hydrochloric acid.This is the method used.
1. Measure 50 cm3 of hydrochloric acid into a polystyrene cup.
2. Measure the temperature of the hydrochloric acid.
3. Add one spatula of metal powder to the hydrochloric acid and stir.
4. Measure the highest temperature the mixture reaches.
5. Calculate the temperature increase for the reaction.
6. Repeat steps 1 to 5 three more times.
7. Repeat steps 1 to 6 with different metals.

The table below shows the student’s results.

Calculate the mean temperature increase X for magnesium in the table above.
Do not include the anomalous result in your calculation.

Question 12

12.

Determine the order of reactivity for the metals cobalt, magnesium and zinc.

Use the table from the previous question

Most:_______ 
Middle:_______ 
Least:_______ 

Question 13

13.

From above, What type of variable is the volume of hydrochloric acid in this investigation?

Control

Dependent

Independent

Question 14

14.

A student investigated the temperature change when zinc reacts with copper sulfate solution.

The student used a different concentration of copper sulfate solution for each experiment.The student used the apparatus shown below.

The student:
•        measured 50 cm3 copper sulfate solution into a glass beaker
•        measured the temperature of the copper sulfate solution
•        added 2.3 g zinc
•        measured the highest temperature
•        repeated the experiment using copper sulfate solution with different concentrations.

The equation for the reaction is:
Zn(s)     +                 CuSO4(aq)               -->     Cu(s)       +              ZnSO4(aq)
zinc       +      copper sulfate solution    -->    copper      +    zinc sulfate solution

The student’s results are shown in the table below.

Describe and explain the trends shown in the student’s results.

Question 15

15.

a. _______ 
b. _______ 
c. _______ 

Question 16

16.

The decomposition of hydrogen peroxide gives out energy to the surroundings

What type of reaction is this?

Displacement

Endothermic

Exothermic

Neutralisation

Question 17

17.

Calculate the mean of the temperature change results. Do NOT use anomalies.

Question 18

18.

A student is given three metals, X, Y and Z to identify.

The metals are magnesium, iron and copper.

Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid.

Your plan should give valid results.

Question 19

19.

Complete the table

Question 20

20.

Endo or exo?

Endothermic

Exothermic

Question 21

21.

Endo or exo?

Endothermic

Exothermic

Question 22

22.

Endo or exo?

Endothermic

Exothermic

Question 23

23.

Endo or exo?

Endothermic

Exothermic

Question 24

24.

• draw the reaction profile
• draw an arrow to show the overall energy change (label this E)
• draw an arrow to show the activation energy (label this A)

CH4 + H2O → CO + 3H2

Energy change = +208 kJ/mol

Question 25

25.

What is the energy change of this reaction?

Question 26

26.

• draw the reaction profile
• draw an arrow to show the overall energy change (label this E)
• draw an arrow to show the activation energy (label this A)

3H2 + N2 → 2NH3

Energy change = –76 kJ/mol

In a chemical cell, also called a voltaic cell, the substance that is most easily
oxidised will give up its electrons to the external circuit and is the anode of the cell.

Question 27

27.

Question 28

28.

Question 29

29.

True

False

Question 30

30.

Question 31

31.

Question 32

32.

Question 33

33.

Other Answer Choices:

Electrolyte

Water

Cathode

Oxygen

Hydrogen

Anode