wayground logo

Free Printable Worksheets

NEW

Font size

S
M
L
XL
Worksheets

Calculating Enthalpy

Total questions: 28

Worksheet time: 45mins

Name
Class
Date
1.

How do you calculate Enthalpy of a reaction?

a)

ΔH = ΔHproducts - ΔHreactants

b)

ΔT = q / mC

c)

ΔG = ΔH -TΔS

d)

E = mc2

2.

What is standard enthalpy of formation, ΔHfo?

a)

Heat change when 1 mole of gaseous ions is hydrated in water at 25oC and 1 atm

b)

Heat change when 1 mole of compound is formed from its elements in their standard states at 25oC and 1 atm

c)

Heat change when 1 mole of gaseous atom is formed from its elements at 25oC and 1 atm

d)

Heat change when 1 mole of electrons is removed from 1 mole of gaseous atoms at ground state at 25oC and 1 atm

3.

Define standard enthalpy 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 state.

d)

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

4.

Which of the following has a ΔHfo value of 0?

a)

Br2(g)

b)

N(g)

c)

CO(g)

d)

Ne(g)

5.

Which of the equation below refers to the standard enthalpy of formation, ΔHfo?

a)

Na(g) ---> Na+(g) + e- ΔH = -364 kJmol-1

b)

C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O (l) ΔH = - 1286 kJmol-1

c)

2C(s) + 2H2(g) ---> C2H4 (g) ΔH = - 52.3 kJmol-1

d)

Na+(g) ---> Na+(aq) ΔH = - 364 kJmol-1

6.

When 1.0 mole of ZnO(s) decomposes,

ZnO(s) ---> Zn(s) + 1/2 O2(g) , enthalpy change is +348 kJ/mol.

What does this tell you about the formation of ZnO (s)?

a)

the formation of ZnO (s) is endothermic

b)

the formation of ZnO (s) is exothermic

c)

the formation of ZnO (s) does not require energy

d)

the formation of ZnO (s) absorbs heat.

7.
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
8.
Endothermic reactions feel
a)
warm
b)
cold
9.
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
10.
Heat is measured in 
a)
joules
b)
grams
c)
degrees celcius
11.
Describe the energy change that takes place when bonds are broken. 
a)
a) Energy is given out 
b)
b) Energy is taken in 
c)
c) Energy is taken in and then given out 
d)
d) Energy is given out and then taken in
12.
Which is an example of an endothermic physical reaction? 
a)
a) Ice melting 
b)
b) Combustion 
c)
c) Steam condensing 
d)
d) Photosynthesis
13.
Which statement is FALSE for an exothermic reaction?
a)
Reactants higher in energy and less stable
b)
Product lower in energy and more stable
c)
Products have stronger bonds than reactants
d)
Reactants have stronger bonds than products
14.
Diagram below shows
a)
Standard lattice enthalpy
b)
Standard enthalpy of precipitation
c)
Standard enthalpy of formation
d)
Standard enthalpy of hydration
15.
ΔH value in an endothermic reaction is a positive number.
a)
True
b)
False
16.
The enthalpy change for the reaction
C(s, graphite) + 1⁄2O2(g) --> CO(g) cannot be measured directly since some carbon dioxide is always formed in the reaction.
It can be calculated using Hess’s Law and the enthalpy changes of combustion of graphite and of carbon monoxide.
C(s, graphite) + O2(g) --> CO2    ΔH=-394 kJmol–1
CO(g) + 1⁄2O2(g) --> CO2  ΔH=-283 kJmol–1  
The enthalpy change for the reaction of graphite with oxygen to give carbon monoxide is 
a)
-677 kJmol–1 
b)
+111 kJmol–1 
c)
-111 kJmol–1 
d)
+677 kJmol–1 
17.

The standard enthalpy changes of combustion of carbon, hydrogen and methane are shown in the table.

Which one of the following expressions gives the correct value for the standard enthalpy change of formation of methane in kJ mol–1?

C(s) + 2H2(g) → CH4(g)

a)

394 + (2 × 286) – 891

b)

–394 – (2 × 286) + 891

c)

394 + 286 – 891

d)

–394 – 286 + 891

18.
Given the following data: ΔH○f[FeO(s)] = –270kJmol–1
ΔH○f [Fe2O3(s)] = –820 kJ mol–1
Select the expression which gives the enthalpy change, in kJ mol–1, for the reaction:
2FeO(s) + 1⁄2O2(g) → Fe2O3(s) 
a)
(–820 × 1⁄2) + 270 = –140
b)
(+820 × 1⁄2) – 270 = +140
c)
–820 + (270 × 2) = –280 
d)
+820 – (270 × 2) = +280 
19.
The standard enthalpy changes of formation of iron(II) oxide, FeO(s), and aluminium oxide, Al2O3(s), are –266 kJ mol–1 and –1676 kJ mol–1 respectively.
What is the enthalpy change under standard conditions for the following reaction?
3FeO(s) + 2Al (s)   ->   3Fe(s) + Al2O3(s) 
a)
+878kJ 
b)
–878kJ 
c)
–1942kJ 
d)
–2474kJ 
20.
C2H4(g) + H2(g)   ->   C2H6(g)  ∆H°=-137 kJ mol-1
Which statement about this information is correct?
a)
The total energy of the bonds broken in the reactants is greater 
than the total energy of the bonds 
formed in the product 
b)
The bonds broken and the bonds made are of the same strength 
c)
The total energy of the bonds broken in the reactants is less than the total energy of the bonds formed in the product 
d)
No conclusion can be made about the sums of the bond enthalpies in the product compared with the reactants 
21.
a)
-296.1
b)
226
c)
-11
d)
255.95
22.
a)
226
b)
255
c)
233
d)
11.3
23.
a)
-233
b)
-11.3
c)
-805
d)
-226
24.
a)
256
b)
202
c)
233
d)
804
25.
a)
-804.6
b)
-202.3
c)
-296.1
d)
-233.0
26.
Calculate the change in enthalpy, ΔH, for the reaction: 
NH4Cl(s) ---> NH3 (g) + HCl(g) 
a)
176.9 kJ
b)
84.4 kJ
c)
-2.29 kJ
d)
34.4 kJ
27.

Calculate the change in enthalpy, ΔH, for the reaction:

H2O (g) + SnO (s) ---> H2 (g) + SnO2 (s)

ΔHf SnO (s) = -285 KJ/mol

a)

-53.88 kJ

b)

84.4 kJ

c)

-83.2 kJ

d)

34.4 kJ

28.
Calculate the change in enthalpy, ΔH, for the reaction: 
2 H2S(g) + 3 O2(g) ---> 2 H2O(l) + 2 SO2(g) 
a)
-1123.6 kJ
b)
-994.5 kJ
c)
1004.2 kJ
d)
992.2 kJ

Similar Resources on Wayground

Unit 2 - Bonding/Naming

25 questions

Unit 2 - Bonding/Naming

quiz

Worksheet

•

10th - 12th Grade

Ôn tập KTGKI - Hoá học

23 questions

Ôn tập KTGKI - Hoá học

quiz

Worksheet

•

12th Grade

Chemistry Test Review

24 questions

Chemistry Test Review

quiz

Worksheet

•

10th - 12th Grade

BÀI TẬP CACBOHDRAT

23 questions

BÀI TẬP CACBOHDRAT

quiz

Worksheet

•

12th Grade

Enthalpy L3 Y2

23 questions

Enthalpy L3 Y2

quiz

Worksheet

•

12th Grade

oxidator of reductor

24 questions

oxidator of reductor

quiz

Worksheet

•

8th - 12th Grade

kiem tra giua ki 1

25 questions

kiem tra giua ki 1

quiz

Worksheet

•

1st Grade - University

Ujian Kimia Semester 1

25 questions

Ujian Kimia Semester 1

quiz

Worksheet

•

12th Grade