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WorksheetsEnthalpy 1
Total questions: 20
Worksheet time: 11mins
How do you calculate Enthalpy of a reaction?
ΔH = ΔHproducts - ΔHreactants
ΔT = q / mC
ΔG = ΔH -TΔS
E = mc2
Define standard enthalpy of combustion.
Heat released when one mole of substance is burnt completely in excess oxygen.
Heat absorbed when one mole of substance is burnt completely in excess oxygen under standard state.
Heat released when one mole of substance is burnt completely in excess oxygen under standard state.
Heat change when one mole of substance is burnt partially in excess oxygen under standard state.
Which of the equation below refers to the standard enthalpy of formation, ΔHfo?
Na(g) ---> Na+(g) + e- ΔH = -364 kJmol-1
C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O (l) ΔH = - 1286 kJmol-1
2C(s) + 2H2(g) ---> C2H4 (g) ΔH = - 52.3 kJmol-1
Na+(g) ---> Na+(aq) ΔH = - 364 kJmol-1
What do we mean by the term standard conditions
1atm, 20C and 1moldm3
1atm, 0K and 1moldm3
10atm, 273K and 10mol/dm3
100kPa, 298K and 1mol/dm3
Define the term Exothermic by picking the correct statements
Products have less energy than the reactants
ΔH is negative
ΔH is positive
Energy is given out to the surroundings (temperature goes up).
products have more energy than the reactants
Define Endothermic by picking the correct statements
ΔH is positive
Energy is taken in from the surroundings (temperature goes down).
Energy is given out to the surroundings (temperature goes up).
· Products have less energy than the reactants
products have more energy than the reactants
What is the Law of Conservation of Energy?
Energy is equal to reactants and products
Energy can be created nor destroyed
Energy is used up but it can be replenish
Energy is conserved and preserved
Study the reaction below. Is it exothermic or endothermic?
H2 + Cl2 --> 2 HCl + 1845 kJ
Exothermic Reaction
Endothermic Reaction
According to the Particles Theory of Matter, one particle has the ability to vibrate within their mean position if added with heat. Which of the following is the statement referring to?
Solid
Liquid
Gas
Hfinal > Hinitial means _____
change of enthalpy is positive and system absorbs heat
change of enthalpy is negative and system absorbs heat
change of enthalpy is positive and system loses heat
change of enthalpy is negative and system loses heat
Which of these equations could represent a standard enthalpy change of combustion? (They are all correctly balanced)
2 C4H10 (g) + 13 O2 (g) → 8 CO2 (g) + 10 H2O (l)
C4H10 (g) + 6.5 O2 (g) → 4 CO2 (g) + 5 H2O (l)
C4H10 (g) + 4.5 O2 (g) → 4 CO (g) + 5 H2O (l)
C4H10 (g) + 6.5 O2 (g) → 4 CO2 (g) + 5 H2O (g)
Standard enthalpy change of combustion, ΔcHΘ, is the enthalpy change that takes place when ....... .......... (two words) of a substance reacts completely with oxygen under standard conditions (with all reactants and products in standard states).
(a)
What value in kJ mol-1 is the standard enthalpy change of formation, ΔfHΘ, of any element?
(a)
Which of these is the correct form of the calorimetry equation?
q = mc ÷ ΔT
q = mΔT
q = mcΔT
q = mcT
What is this?
Standard enthalpy change of formation,
Standard enthalpy change of reaction
Enthalpy change of combustion
Standard enthalpy change of formation
What is the name of this enthapyl change
Enthalpy change of formation
Enthalpy change of combustion
Enthalpy change of reaction
Enthalpy change of atomisation
N2 + 3H2 --> 2NH3 ΔH = - 33 kJ
exothermic reaction
endothermic reaction
reaction with catalyst
equilibrium reaction
NH4NO3 --> NH4+ +NO3-
ΔH = + 27 kJ
endothermic reaction
exothermic reaction
reaction with catalyst
equilibrium reaction
