WorksheetsChemistry-26 Chemical energetics
Total questions: 18
Worksheet time: 22mins
Which of the following is true about the formation of bonds between molecules?
Energy is given off when bonds are formed between molecules.
Energy is absorbed by the molecule when bonds are formed.
Energy is neither given off nor absorbed when bonds are formed.
Which reaction is endothermic?
acid neutralising alkali causing a temperature increase
adding magnesium to hydrochloric acid
calcium carbonate decomposing when heated combustion of fossil fuels
What type of reaction is this?
Exothermic
Endothermic
Energy Producing
No way to tell
The graph above is from which type of reaction?
Endothermic reaction
Exothermic reaction
Which of the following energy changes corresponds to the activation energy required for the forward reaction to take place?
A
C
B
E
Hydrogen gas burns in air to form water.
2H2 (g) + O2 (g) → 2H2O(I) ΔH= - 572 kJ
How much heat energy (in kJ) is given off if a rocket carrying 200.0 kg of hydrogen gas is burnt in excess oxygen?
1.43 x 107
2.86 x 107
4.92 x 107
A
B
C
D
A
B
C
D
A
B
C
D
A
B
C
D
Using the equations below:
C(s) + O2(g) → CO2(g) ∆H = –390 kJ
Mn(s) + O2(g) → MnO2(s) ∆H = –520 kJ
what is ∆H (in kJ) for the following reaction?
MnO2(s) + C(s) → Mn(s) + CO2(g)
910
130
-130
2 NO ⟶ N2 + O2 (ΔH = -180.5 kJ)
N2 + 2 O2 ⟶ 2 NO2 (ΔH = + 66.36 kJ)
Calculate the entalphy for :
2 NO + O2 ⟶ 2 NO2 (ΔH = ?)
Is the overall process exothermic or endothermic?
-114.14 kJ,
exothermic
+114.14 kJ, endothermic
246.9 kJ, endothermic
-246.9 kJ, exothermic
For the reaction 2H2(g) + O2(g) → 2H2O(g) the bond enthalpies (in kJ/mol) are
H-H = x, O=O = y, O-H = z
Which calculation will give the value, in kJ/mol, of ΔH for the reaction?
2x + y - 2z
4z - 2x - y
2x + y - 4z
2z - 2x - y
When the solids Ba(OH)2 and NH4SCN are mixed, a solution is produced and the temperature drops. Which statement about the energetics of this reaction is correct?
The reaction is endothermic and ΔH is negative
The reaction is endothermic and ΔH is positive
The reaction is exothermic and ΔH is negative
The reaction is exothermic and ΔH is positive
