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WorksheetsThermodynamics/Energetics
Total questions: 39
Worksheet time: 59mins
Q= m c ∆T
The units for specific heat are:
________________
What is the temperature of the metal cube when thermal equilibrium is achieved between the cube and the liquid?
There are four cups of hot cocoa. The cup sizes are shown. The temperature of the cocoa in each cup is 25 degrees celsius. Which cup has the MOST heat?
Large cup (Trenta)
Small cup (Tall)
Venti
All three are the same temperature so they have same heat.
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
A metal cube with a mass of 55grams at temperature of 85°C is immersed in 150grams of water at temperature of 20°C. The metal and water then reach a final temperature of 23oC. How much heat does the water gain?
1881 J
690 J
14253 J
38874 J
A metal cube with a mass of 55grams at temperature of 85°C is immersed in 150grams of water at temperature of 20°C. The metal and water then reach a final temperature of 23oC. How much heat does the metal lose?
-1881 J
-690 J
-14253 J
-38874 J
A metal cube with a mass of 55grams at temperature of 85°C is immersed in 150grams of water at temperature of 20°C. The metal and water then reach a final temperature of 23oC. What is the specific heat of the metal?
0.55 J/goC
2120 J/goC
11.4 J/goC
4.18 J/goC
0.75 J/goC
ΔH value in an endothermic reaction is a:
positive number.
negative number.
Which example would be considered exothermic?
Melting Ice
Photosynthesis
Making ice cubes
Cooking an egg
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.
Which of the following phase changes is exothermic?
melting
evaporation
freezing
All of these phase changes are exothermic
None of these phase changes are exothermic
Using a table that lists standard heats of formation, you can calculate the change in enthalpy for a given chemical reaction. The change in enthalpy is equal to
ΔHf of products minus ΔHf of reactants.
ΔHf of products plus ΔHf of reactants.
ΔHf of reactants minus ΔHf of products
ΔHf of reactants plus ΔHf of products
Calculate ΔHrxn for the reaction of sulfur dioxide with oxygen. 2SO2(g) + O2(g) → 2SO3(g)
(ΔH0f (SO2) = –296.8 kJ/mol; ΔH0f (SO3) = –395.7 kJ/mol)
–98.9 kJ
–197.8 kJ
98.9 kJ
197.8 kJ
Calculate the energy released when 24.8 g Na2O reacts in the following reaction. Na2O(s) + 2HI(g) →2NaI(s) + H2O(l)
ΔH = –120.00 kcal
0.207 kcal
2.42 kcal
48.0 kcal
3.00 × 102 kcal
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 average bond enthalpies for O-O and O=O are 146kJ/mol and 496kJ/mol respectively. Calculate the enthalpy change for the reaction shown.
-102kJ
+102kJ
+146kJ
-248 kJ
Given the following data: ΔH○f[FeO(s)] = –270kJmol–1
ΔH○f [Fe2O3(s)] = –820 kJ mol–1
Select the expression which gives the enthalpy change, in kJ mol–1, for the reaction:
2FeO(s) + 1⁄2O2(g) → Fe2O3(s)
(–820 × 1⁄2) + 270 = –140
(+820 × 1⁄2) – 270 = +140
–820 + (270 × 2) = –280
+820 – (270 × 2) = +280
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(g) + 5H2(l) + ½O2(g) -> C4H9OH(l)
c – 4a – 5b
2a + 10b - c
4a + 5b - c
2a + 5b + c
Calculate the enthalpy change, ΔH in kJ, for the reaction
NO(g) + O2(g) → NO2(g)
Use the following:
½N2 (g) + ½O2 (g)→ NO(g) ΔH = +90.25kJ
½N2 (g) + O2 (g)→ NO2(g) ΔH = +33.18kJ
-123.43kJ
+123.43kJ
+57.07 kJ
-57.07 kJ
Given the equation I2(s) + 62.4 kJ → I2(g), which of the following is true?
ΔH = +62.4 kJ
The reaction is exothermic.
ΔH = -62.4 kJ
The reaction releases heat
Define standard enthalpy of combustion.
Heat released when one mole of substance is burned completely in excess oxygen.
Heat absorbed when one mole of substance is burned completely in excess oxygen under standard state.
Heat released when one mole of substance is burned completely in excess oxygen under standard state.
Heat change when one mole of substance is burned partially in excess oxygen under standard state.
Which of the following has a ΔHfo value of 0?
Br2(g)
N(g)
CO(g)
Ne(g)
What does the circle mean in ΔH°?
Standard Conditions (T=298.15 K P=100 kPa)
Standard Temperature and Pressure (T=273.15 K P=100 kPa)
Degree K
Degree C
What is standard enthalpy of formation, ΔHfo?
Heat change when 1 mole of gaseous ions is hydrated in water at 25oC and 1 atm
Heat change when 1 mole of compound is formed from its elements in their standard states at 25oC and 1 atm
Heat change when 1 mole of gaseous atom is formed from its elements at 25oC and 1 atm
Heat change when 1 mole of electrons is removed from 1 mole of gaseous atoms at ground state at 25oC and 1 atm
Use the information in the image to answer this question.
The standard enthalpy of combustion of butane, in kJ mol−1, is
−2880
−2590
−806
−554
The enthalpy diagram shown represents an
exothermic reaction.
endothermic reaction.
The enthalpy diagram shown represents an
exothermic reaction.
endothermic reaction.
25.0 mL of 2.0M HCl is neutralized by 25.0 mL of 2.0M NaOH in a calorimeter. The starting temperature of each solution is 15.0 °C and following the reaction the temperature is 22.5°C. Calculate the heat of reaction. Make the usual assumptions regarding specific heat and density of solution.
1.6 kJ
-1.6 kJ
31 kJ/mol
-31 kJ/mol
