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Enthalpy L3 Y2

Total questions: 23

Worksheet time: 16mins

Name
Class
Date
1.

Match the definition below to the correct term.

The enthalpy change that takes place when one mole of a compound is formed from its elements in their standard states under standard conditions.

a)

The enthalpy change of hydration

b)

The enthalpy change of combustion

c)

The enthalpy change of formation

d)

The enthalpy change of reaction

2.

What do we mean by the term standard conditions

a)

1atm, 20C and 1moldm3

b)

1atm, 0K and 1moldm3

c)

10atm, 273K and 10mol/dm3

d)

100kPa, 298K and 1mol/dm3

3.

Define the term exothermic by picking all the correct statements

a)

products have less energy than the reactants

b)

ΔH is negative

c)

ΔH is positive

d)

Energy is given out to the surroundings (temperature goes up).

e)

products have more energy than the reactants

4.

Define endothermic by picking all the correct statements

a)

ΔH is positive

b)

Energy is taken in from the surroundings (temperature goes down).

c)

Energy is given out to the surroundings (temperature goes up).

d)

Products have less energy than the reactants

e)

Products have more energy than the reactants

5.
What type of reaction is shown in the reaction pathway?
a)
endothermic reaction
b)
exothermic reaction
6.
The SI unit of heat and energy is the __________.
a)
calorie
b)
heat
c)
joule
d)
watt
7.

Define standard enthalpy change of combustion.

a)

Heat released when one mole of substance is burnt completely in excess oxygen.

b)

Heat absorbed when one mole of substance is burnt completely in excess oxygen under standard state.

c)

Heat released when one mole of substance is burnt completely in excess oxygen under standard conditions with all substances being in their standard states.

d)

Heat change when one mole of substance is burnt partially in excess oxygen under standard state.

8.
Define 'Enthalpy'
a)
a) Energy stored in the movement of molecules in a substance
b)
b) The opposite of temperature
c)
c) The temperature of a molecule
d)
d) Energy stored in the chemical bonds in a substance
9.
Which statement is true regarding endothermic reactions?
a)
a) Temperature change is positive and enthalpy change is positive
b)
b) Temperature change is positive and enthalpy change is negative
c)
c) Temperature change is negative and enthalpy change is positive
d)
d) Temperature change is negative and enthalpy change is negative
10.

What does the circle mean in ΔH°?

a)

Standard Conditions

b)

Standard Temperature and Pressure

c)

Degree K

d)

Degree C

11.

Match the definition to the correct term.

The enthalpy change that accompanies a reaction in the molar quantities shown in a chemical reaction under standard conditions with all reactants and products in their standard states.

a)

The enthalpy change of formation

b)

The enthalpy change of reaction

c)

The enthalpy change of combustion

d)

The enthalpy change of hydration

12.
ΔH value in an endothermic reaction is a positive number.
a)
True
b)
False
13.
A catalyst works by
a)
changing the order of the reaction
b)
increasing the temperature
c)
lowering the activation energy
d)
making the activated complex
14.
What type of reaction is shown in the reaction pathway?
a)
endothermic reaction
b)
exothermic reaction
15.

How do you calculate Enthalpy of a reaction?

a)

ΔH = ΔHproducts - ΔHreactants

b)

ΔT = q / mC

c)

ΔH = ΔHreactants - ΔHproducts

d)

q = mcΔT

16.

Enthalpy changes of hydration values are always positive

a)

True

b)

False

17.
Which statement is true regarding endothermic reactions?
a)
a) Temperature change is positive and enthalpy change is positive
b)
b) Temperature change is positive and enthalpy change is negative
c)
c) Temperature change is negative and enthalpy change is positive
d)
d) Temperature change is negative and enthalpy change is negative
18.
Endothermic reactions feel
a)
warm
b)
cold
19.

Which statement is true regarding exothermic reactions?

a)
a) Temperature change is positive and enthalpy change is positive
b)
b) Temperature change is positive and enthalpy change is negative
c)
c) Temperature change is negative and enthalpy change is positive
d)
d) Temperature change is negative and enthalpy change is negative
20.

Enthalpy changes of combustion values are always negative

a)

True

b)

False

21.

Match the definition below to the correct term.

The enthalpy change that takes place when one mole of gaseous ions is dissolved in an infinitely dilute solution under standard conditions.

a)

The enthalpy change of hydration

b)

The enthalpy change of combustion

c)

The enthalpy change of formation

d)

The enthalpy change of reaction

22.

A reaction that gives out energy to the surroundings causes the surroundings ....

a)

temperature to drop

b)

temperature to rise

c)

temperature to remain constant

d)

temperature to vary

23.

Enthalpy changes of formation values are always positive

a)

True

b)

False