WorksheetsUnit 4 - lesson 2
Total questions: 12
Worksheet time: 36mins
The chemical eqation for the decomposition of magnesium carbonate is as follows :
MgCO3(s) + 117 KJ = MgO(s) + CO2(g)
Based on this chemical equation. Which of this statement is true ?
1. 117 kJ of energy is released when a single molecule of MgCO3 decomposes.
2. 117 kJ of energy is released when 1 mole of MgCO3 decompose.
3. 117 kJ of energy is needed to make 1 mole of MgCO3 decompose.
4. 117 kJ of energy is needed to make 42 g of MgCO3 decompose
5. 117 kJ of energy is needed to make a single molecule of MgCO3 decompose.
The value of Δ𝐻 when liquid water freezes to solid water is −6.01 kJ/mol.What is the value of Δ𝐻 when solid water melts to liquid water? ………………… KJ
(+3.01)
(+6.01)
(+4.01)
(+12.01)
The chemical equation for the combustion of glucose is shown:
C6H12O6(s) + 6O2(g) = 6CO2(g) + 6H2O(l) + 2808 KJ
How much energy is released when 2.5 moles of glucose are burned?……………… KJ
4352
7020
2808
2332
The symbol for standard enthalpy change is Δ𝐻°.
Which of the following is not a standard condition?
1. A volume of 1 m3
2. A pressure of 1 bar for gases
3. All components in their standard state
4. A concentration of 1 mol/dm3 for solutions
The molar bond energy of F2 is 159 kJ/mol.Calculate the energy of one F-F bond.
1. 1.65 x 10-19 J
2. 2.64 x 10-19 J
3. 9.58 x 10-19 J
4. 3.78 x 10-19 J
5. 2.55 x 10-19 J
3.70 mol of Cl-Cl bonds release 888 kJ of energy when they form. How much energy is released when 1000 Cl-Cl bonds form?
1. 3.99 x 10-16 J
2. 1.48 x 10-15 J
3. 3.99 X 10-19 J
4. 1.48 X 10-18 J
5. 4.01 X 10-17 J
Which of the following quantities of bonds requires the most energy to break?
1. 5.8 mol I-I (148 KJ/mol)
2. 1.0 mol (835 KJ/mol)
3. 2.0 mol H-Cl ( 428 KJ/mol)
4. 2.0 mol H-H (436 KJ/mol)
5. 1.7 mol O=O (494 KJ/mol)
Which of the following are units for the molar enthalpy change of a reaction, Δ𝐻?
1. mol/dm3
2. ∘C/atom
3. kJ/mol
4. cm3/s
5. g/mol
A student is setting up an experiment to measure the enthalpy change in a neutralization reaction between hydrochloric acid and potassium hydroxide. Before mixing the two solutions together in a polystyrene cup, the student places a beaker of each solution in a water bath set to 25oC .Why does the student do this?
1. To ensure the reactants have the correct activation energy needed to react
2. To make the solutions less viscous
3. To ensure both solutions are at the same temperature as each other
4. To increase the rate of reaction between the hydrochloric acid and the potassium hydroxide
5. To remove any impurities in the solutions
Which of the following is the best definition of an endothermic reaction?
1. A reaction that gives out heat
2. A reaction that is accelerated by heating
3. A reaction that is accelerated by cooling
4. A reaction that is spontaneous
5. A reaction that absorbs heat
A chemical reaction has a reaction enthalpy of −512 kJ/mol.Is it endothermic or exothermic?
1. Endothermic
2. Exothermic
Which of the following is a more accurate description of the combustion reaction?
1. Combustion is an endothermic reaction because energy is produced in the form of heat.
2. Combustion is an exothermic reaction because energy is not produced.
3. Combustion is an exothermic reaction because chemical energy is converted to heat.
4. Combustion is an exothermic reaction because heat is converted to chemical energy.
5. Combustion is an endothermic reaction because thermal energy is released.
