WorksheetsConcept of Enthalpy
Total questions: 20
Worksheet time: 18mins
How do you calculate Enthalpy of a reaction?
ΔH = ΔHproducts - ΔHreactants
ΔT = q / mC
ΔG = ΔH -TΔS
E = mc2
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.
The enthalpy of neutralisation
The enthalpy of combustion
The enthalpy of formation
The enthalpy of reaction
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
1. The temperature increases when calcium chloride dissolves in water.
2. Steam condenses to liquid water
3. Water boils
4. Dry ice sublimates
Which of the following represent the enthalpy change of atomization?
O2(g) → 2 O(g)
Mg(s) → Mg(g)
Mg(s) + Cl2(g) → MgCl2(s)
Ca(g) → Ca2+(g) + 2 e
which of the following enthalpy changes represent the enthalpy change of formation?
Mg(s) + Cl2(g) → MgCl2(s)
Mg2+(g) + 2 Cl -(g) → MgCl2(aq)
O2(g) → 2 O(g)
2Mg (s) + O2(g) → 2MgO(S)
which of the following represent the enthalpy change of hydration?
Mg(s) → Mg2+(g)
Mg(s) → Mg2+(g) + 2 e
Cl2(g) + (aq)→ 2Cl(aq)
Mg2+(g) → Mg2+(aq)
Which of the following represent enthalpy change of solution?
Cl2(g) ---> 2Cl-(aq) .
Mg2+(g) ---> Mg2+(aq)
MgCl2(s) ---> Mg2+(aq) + 2Cl-(aq) .
Mg2+(g) + 2Cl-(g) ---> Mg2+(aq) + 2Cl-(aq)
MgCl2(s) ---> Mg2+(g) + 2Cl-(g)
This equation represents
Enthalpy of hydration
Enthalpy of solution
Lattice enthalpy of dissociation
Lattice enthalpy of formation
which of the following represent the equation for enthalpy of sublimation
1/2 Br (s) → Br(g)
1/2 I 2(s) → I(g)
1/2 O(g) → 2 O(g)
Mg(s) → Mg2+ (g) + 2e
Which of the following equations represents the enthalpy change of combustion?
2C4H10(g) +13O2(g) → 8CO2 (g) + 10H20(g)
C4H10(g) +13/2O2(g) → 4CO2 (g) + 5H20(g)
C4H10 + 9/2O2 = 4CO (s)+ 5H2O
C4H10 + 5/2O2 = 4C(s) + 5H2O(g)
Which one represent the electron affinity of chlorine?
1/2Cl2(g) → 2 Cl(g)
Cl(g) + e → Cl- (g)
1/2 Cl2(g) + e → Cl- (g)
Cl2(g)→ 2 Cl-(g) + 2e-
which of the following represent the enthalpy change of 1st ionization enthalpy?
Mg(s) --> Mg2+(g) + 2e-(aq)
Mg(s) --> Mg+(g) + e-(aq)
Mg(s) --> Mg+(g) + e-(aq)
Mg(g) --> Mg+(g) + e-(aq)
which of the following represent the lattice enthalpy of formation of sodium flouride
2Na(g) + F2(g) → 2NaF(g)
Na(s) + 1/2F2(g) → NaF(s)
2Na(s) + 1/2F2(g) → NaF(g)
2Na(s) + F2(g) → 2NaF(g)
