Self Assessment B


1	An endothermic process
		A)	raises the temperature of one gram of a substance by one degree Celcius.
		B)	takes in heat from the surroundings.
		C)	increases the acidity of the surroundings.
		D)	gives off heat to the surroundings.
		E)	releases carbon dioxide into the surroundings.


2	The chemical equation describing the conversion of SO₂ into SO₃ is shown below. Calculate (H when 89.6 g of SO₂ is converted into SO ₃. SO₂(g) + ½O₂(g) ----> SO₃(g) DH^o_rxn = -99.1 kJ
		A)	-69.3 kJ
		B)	-139 kJ
		C)	69.3 kJ
		D)	139 kJ
		E)	-111 kJ


3	How many calories are required to heat 25.0 g of platinum (specific heat capacity = 0.032 cal/g.K) from 24.5 ^oC to 75.0 ^oC?
		A)	48 cal
		B)	20 cal
		C)	80 cal
		D)	40 cal
		E)	None of the above.


4	If a substance has a specific heat capacity of 1.0 J/g·^oC and a density of 2.0 g/mL, how much heat would be required to raise the temperature of 100 mL of the substance from 25 to 45 ^oC?
		A)	0.20 kJ
		B)	2.0 kJ
		C)	4.0 kJ
		D)	8.0 kJ


5	A 0.468-g sample of pentane (C₅H₁₂) was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.00 kg of water rose from 20.45 to 23.65 ^oC. The specific heat capacity of the calorimeter is 2.21 kJ/ ^oC, and the specific heat capacity of water is 4.184 J/g·^oC. What is the heat of combustion of one mole of C₅ H₁₂?
		A)	-7.07 x 10³ kJ/mol
		B)	-2.05 kJ/mol
		C)	-3.16 x 10³kJ/mol
		D)	1.34 x 10⁴ kJ/mol
		E)	3.16 x 10³ kJ/mol


6	Calculate the standard heat of formation of carbon disulfide (CS₂) from its elements, C(s) + 2 S(s) ----> CS₂(l), given that: C(s) + O₂(g) ----> CO₂(g), DH = -393.5 kJ; S(s) + O₂(g) ----> SO₂(g), DH = -296.8 kJ; and CS₂(l) + 3 O₂(g) ----> CO₂(g) + 2 SO₂(g), DH = -1076.8 kJ.
		A)	-1767.1 kJ
		B)	-386.5 kJ
		C)	89.7 kJ
		D)	386.5 kJ
		E)	None of the above


7	For which of the substances below is DH^o_f = 0?
		A)	O₂(g)
		B)	N₂(l)
		C)	Na(g)
		D)	Xe(l)
		E)	A and B


8	To which of the following reactions occurring a 25 ^oC does the symbol DH^o_f [H₂O(l)] apply?
		A)	H₂O(l) ----> 2 H(g) + O(g)
		B)	2 H(g) + O(g) ----> H₂O(l)
		C)	H₂(l) + ½O₂(l) ----> H₂O(l)
		D)	H₂(g) + ½O₂(g) ----> H₂O(l)
		E)	H₂O(g) ----> H₂O(l)


9	The heat of solution of KCl is 17.2 kJ/mol, and the combined heats of hydration of one mole of gaseous chloride ions and one mole of gaseous potassium ions is -698 kJ. What is the lattice energy of potassium chloride?
		A)	-681 kJ/mol
		B)	715 kJ/mol
		C)	-715 kJ/mol
		D)	-332 kJ/mol
		E)	681 kJ/mol


10	A certain gas expands in volume from 2.0 L to 24.5 L at constant temperature. Calculate the work done by the gas if it expands against a constant pressure of 5 atm.
		A)	-112.5 J
		B)	1.24 x 10⁴ J
		C)	-1.14 x 10⁴ J
		D)	113 J
		E)	1.14 x 10⁴ J

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