WorksheetsEnergetics2
Total questions: 30
Worksheet time: 12mins
In which one of the following reactions is the standard enthalpy change equal to the standard enthalpy of formation of lithium fluoride?
Li(g) + F(g) → LiF(s)
Li+(g) + F−(g) → LiF(s)
Li+(aq) + F−(g) → LiF(s)
Li(s) + 0.5F2(g) → LiF(s)
What is the temperature rise, in K, when 504 J of heat energy are absorbed by 0.110 kg of solid iron?
Specific heat capacity of iron = 0.448 J K−1 g−1
9.78 × 10−2
1.02 × 101
2.83 × 102
1.02 × 104
The table shows the standard enthalpy of formation, ΔfHθ, for some of the substances in the reaction
C2H6(g) + 6F2(g) ⟶ C2F6(g) + 6HF(g) ΔHθ = −2898 kJ mol−1
What is the standard enthalpy of formation, in kJ mol−1, for HF(g)?
−1638
−273
+273
+1638
Using the information given, answer this question.
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(g)
ΔH⦵= +96 kJ mol−1, ΔS⦵ = +138 J K−1 mol−1
The standard enthalpy of formation of steam is
+286 kJ mol−1
+242 kJ mol−1
−242 KJ mol−1
−286 kJ mol−1
Q= m c ∆T
The units for specific heat are:
Copper, Stainless Steel, Carbon Steel, and Zinc were all heated using 10,000 JOULES of thermal energy. Based on the chart, which material would have the SMALLEST change in temperature?
Copper
Carbon Steel
Zinc
Stainless Steel
In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. What is true?
This chemical reaction is releasing energy and is exothermic.
This chemical reaction is absorbing energy and is exothermic.
This chemical reaction is releasing energy and is endothermic.
This chemical reaction is absorbing energy and is endothermic.
None of these are true.
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)
+878kJ
–878kJ
–1942kJ
–2474kJ
The enthalpies of combustion of C(s), H2(g) and C4H9OH(l) (in kJmol-1) are as follows
C(s) + O2(g) → CO2(g) ∆H=a
H2(g) + ½O2(g) → H2O(l) ∆H=b
C4H9OH(l) + 6O2(g) → 4CO2(g) + 5H2O(l) ∆H=c
What is the enthalpy change for the reaction shown below?
4C(s) + 5H2(l) + ½O2(g) -> C4H9OH(l)
c – 4a – 5b
2a + 10b - c
4a + 5b - c
2a + 5b + c
Which is correct about energy changes during bond breaking and bond formation?
Which statement about this information is correct?
than the total energy of the bonds
formed in the product
Enthalpy (H)
The heat content of a system at constant pressure.
A chemical equation that includes the amount of heat released or absorbed during the reaction.
The heat released or absorbed during a chemical reaction.
The heat released after burning 1 mole of a substance.
Which equation represents the standard enthalpy of atomisation?(HL)
1/8 S 8 (s) -> S (g)
Na (s) -> Na (l)
Cl2 (g) -> 2Cl (g)
CH4 (g) -> C (g) + 2H2 (g)
Which of the following equation shows ∆Hθsolution ?(HL)
Na+ (g) → Na+ (aq)
NH3 (g) → NH3 (aq)
NaOH (aq) → Na+ (aq) + OH- (aq)
NaCl (s) → Na+ (aq) + Cl- (aq)
Which of the following equation shows lattice energy ?(HL)
Na+ (g) → Na+ (s)
2Na+ (g) + O2- (g) → Na2O (s)
Na+ (g) + OH- (g) → NaOH (aq)
NaCl (s) → Na+ (g) + Cl- (g)
Which of the following represents ∆Hθatom of CH3CH2CH3?
8 B.E. (C-H) + 3 B.E (C-C)
8 B.E. (C-H) + 2 B.E (C-C)
– 8 B.E. (C-H) – 3 B.E (C-C)
– 8 B.E. (C-H) – 2 B.E (C-C)
Calculate the enthalpy change represented by X(HL)
+695kJ/mol
-695kJ/mol
-635kJ/mol
-635kJ/mol
which of the following results in decrease in enthropy(HL)
For a chemical reaction to be feasible, the total entropy change must be zero. (∆Ssystem + ∆Ssurroundings = 0)(HL)
True
False
Which represents a -ΔS?(HL)
ice melting
salt dissolving
water heating up
none of these
Spontaneous reactions are driven by(HL)
increasing enthalpy and increasing entropy.
decreasing enthalpy and decreasing entropy.
increasing enthalpy and decreasing entropy.
decreasing enthalpy and increasing entropy.
The reaction
A + 2 B2 + C --> CAB4
has an enthalpy change of -104 kJ and a change in entropy of -60.8 J/K at 30 °C. What is the free energy and spontaneity of the reaction? (HL)
-85.6 kJ, spontaneous
-18.3 kJ, not spontaneous
+18.3 kJ, spontaneous
+85.6 kJ, not spontaneous
What are standard conditions for energy change?
Pressure of 100 kPa and temperature of 298 K
All solutions are 1 mol/dm3
All substances are in the solid state
All substances are in the gaseous state
Diagram below shows(HL)
Standard lattice enthalpy
Standard enthalpy of precipitation
Standard enthalpy of formation
Standard enthalpy of hydration
Identify the enthalpy change represented by letter f.(HL)
enthalpy of formation
enthalpy of lattice formation
electro affinity of bromine
enthalpy of atomization of zinc
Which one of the following provides the correct values of the activation energy (in kJ mol-1) and the ΔH (in kJ mol-1) for the reaction
1. Calculate the standard entropy change for the following reaction(HL)
Cu(s) +1/2 O2(g) =>CUO (s)
Given that
195.66 J/K.mol
93.09 J/K.mol
-93.09 J/K.mol
+195.66 J/K.mol
S(s) + H2(g) -> H2S(g) ∆H=p
H2(g) + ½O2(g) -> H2O(l) ∆H=q
S(s) + O2(g) -> SO2(g) ∆H=r
H2S(g) + 1½O2(g) -> H2O(l) + SO2(g) ∆H=s
Which statements about exothermic reactions are correct?
I. They have negative ΔH values.
II. The products have a lower enthalpy than the reactants.
III. The products are more energetically stable than the reactants.
I and II only
I and III only
II and III only
I, II and III
