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Chemistry Straighterline Exam/460 Questions with fully solved solutions
Chemistry Straighterline Exam/460 Questions with fully solved solutions
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Chemistry Straighterline Exam/460 Questionswith fully solved solutions
An endothermic reaction causes the surroundings to:
A. warm up
B. become acidic
C. condense
D. decrease in temperature
E. release CO2 - -D
-An exothermic reaction causes the surroundings to:
A. warm up
B. become acidic
C. expand
D. decrease its temperature
E. release CO2 - -A
-Copper metal has a specific heat of 0.385 J/g•oC and has a melting point of
1083oC.
calculate the amount of heat required to raise the temperature of 22.8 g of
Cu from 20.0oC to 875oC.
A. 1.97 10 ─ 5 J
B. 1.0 10 ─ 2 J
C. 329 J
D. 7.51 kJ
E. 10.5 kJ - -D
-Calculate the amount of heat necessary to raise the temperature of 12.0 kg
of water from 15.4oC to 93.0oC.
A. 0.027 kJ B. 324 kJ C. 389 kJ D. 931 kJ
E. 3890 kJ - -E
-How much heat is required to raise the temperature of 1500 g of water
from 25oC
to 52oC?
A. 1500 kJ B. 169 kJ C. 6.27 kJ D. 40.5 J E. 40.5 kJ - -B
-How many degrees of temperature rise will occur when a 25.0 g block of
aluminum absorbs 10 kJ of heat? The specific heat of Al is 0.900 J/g•oC.
A. 0.44oC B. 22.5oC C. 225oC D. 360oC E. 444oC - -E
-If 325 g of water at 4.2oC absorbs 12.28 kJ, then what is the final
temperature of the water?
A. 4.21oC B. 4.8oC C. 9.0oC D. 13.2oC E. 2938oC - -D
, -A glass containing 200 g of H2O at 20oC was placed into a refrigerator. The
water loses 11.7 kJ as it cools to a constant temperature. What is its new
temperature?
A. 0.013oC B. 4oC C. 6oC D. 14oC E. 34oC - -C
-A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/oC.
What is the specific heat of copper?
A. 0.385 J/g•oC B. 1.83 ´ 104 J/g•oC C. 2.60 J/g•oC D. 1.32 J/g•oC
E. 24.5 J/g•oC - -A
-The specific heat of gold is 0.129 J/g•oC. What is the molar heat capacity of
gold (unit is J/mol•oC)?
A. 0.039 J/mol•oC
B. 0.129 J/mol•oC
C. 25.4 J/mol•oC
D. 39.0 kJ/mol•oC
E. 197 J/mol•oC - -C
-When 0.7521 g of benzoic acid was burned in a calorimeter containing 1000
g of water, a temperature rise of 3.60oC was observed. What is the heat
capacity of the bomb calorimeter, excluding water? The heat of combustion
of benzoic acid is ─26.42 kJ/g.
A. 15.87 kJ/oC
B. 4.18 kJ/oC
C. 5.52 kJ/oC
D. 1.34 kJ/oC
E. 752.1 kJ/oC - -D
-Naphthalene combustion can be used to determine the heat capacity of a
bomb calorimeter. The heat of combustion of naphthalene is 40.1 kJ/g. When
0.8210 g of naphthalene was combusted in a calorimeter containing 1000 g
of water a temperature rise of 4.21oC was observed. What is the heat
capacity of the bomb calorimeter excluding the water?
A. 32.9 kJ/oC
B. 7.8 kJ/oC
C. 1.76 kJ/oC
D. 1.76 kJ/oC
E. 15.3 kJ/oC - -C
-Which of the following processes is endothermic?
a. O2(g) + 2H2(g) 2H2O(g)
b. H2O(g) H2O(l)
c. 3O2(g) + 2CH3OH(g) 2CO2(g) + 2H2O(g)
d. H2O(s) H2O(l) - -D
, -A 100 mL sample of 0.200 M aqueous hydrochloric acid is added to 100 mL
of 0.200 M aqueous ammonia in a calorimeter whose heat capacity is 480 J K
─ 1. The following reaction occurs when the two solutions are mixed.
HCl(aq) + NH3(aq) NH4Cl(aq)
The temperature increase is 2.34oC. Calculate ΔH per mole of HCl
neutralized.
A. 154 kJ B. 44.5 kJ C. 22.5 kJ D. ─22.5 kJ E. ─56.2 kJ - -E
-A 0.1326 g sample of magnesium was burned in an oxygen bomb
calorimeter. The Htotal heat capacity of the calorimeter plus water was 5760
J/oC. If the temperature rise of the calorimeter with water was 0.570oC,
calculate the enthalpy of combustion of magnesium.
Mg(s) + 1/2O2(g) MgO(s)
A. ─3280 kJ/mol B. ─24.8 kJ/mol C. 435 kJ/mol
D. 106 kJ/mol E. ─602 kJ/mol - -E
-Which one of the following reactions occurring at 25oC does the symbol
ΔHof[H2SO4(l)] refer to?
A. 2H(g) + S(g) + 4O(g) H2SO4(l)
B. H2(g) + S(g) + 2O2(g) H2SO4(l)
C. H2SO4(l) H2(g) + S(s) + 2O2(g)
D. H2SO4(l) 2H(g) + S(s) + 4O(g)
E. H2(g) + S(s) + 2O2(g) H2SO4(l) - -E
-Which one of the following reactions occurring at 25oC does the symbol
ΔHof[HNO3(l)] refer to?
A. H(g) + N(g) + O3(g) HNO3(l)
B. 1/2H2(g) + 1/2N2(g) + 3/2O2(g) HNO3(l)
C. HNO3(l) 1/2H2(g) + 1/2N2(g) + 3/2O2(g)
D. HNO3(l) H(g) + N(g) + 3O(g)
E. H2(g) + N2(g) + O3(g) HNO3(l) - -B
-When 0.56 g of Na(s) react with excess F2(g) to form NaF(s) at standard
state conditions, 13.8 kJ of heat
are evolved. What is the standard enthalpy of formation (ΔHof) of NaF(s)?
A. 24.8 kJ/mol B. +570 kJ/mol C. ─24.8 kJ/mol D. ─7.8 kJ/mol
E. ─570 kJ/mol - -E
-Ethanol undergoes combustion according to the equation:
C2H5OH(l) + O2(g) CO2(g) + H2O(l) (Not Balanced)
The standard heat of combustion of ethanol, C2H5OH(l), is ─1366.8 kJ/mol.
Given that:
ΔHof[CO2(g)] = ─393.5 kJ/mol
ΔHof[H2O(l)] = ─285.8 kJ/mol
What is the standard enthalpy of formation of ethanol?
A. 3010 kJ
, B. ─687.6 kJ
C. ─277.6 kJ
D. 687.6 kJ
E. 1367 kJ - -C
-Find the standard enthalpy of formation of ethylene, C2H4(g), given the
following data:
C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(l) ΔHof = ─1411 kJ
C(s) + O2(g) CO2(g) ΔHof = ─393.5 kJ
H2(g) + 1/2O2(g) H2O(l) ΔHof = ─285.8 kJ
A. 52 kJ
B. 87 kJ
C. 731 kJ
D. 1.41 103 kJ
E. 2.77 103 kJ - -A
-Octane (C8H18) undergoes combustion according to the following
thermochemical equation:
2C8H18(l) + 25O2(g) 16CO2(g) + 18H2O(l) ΔHorxn = ─11,020 kJ.
Given that: ΔHof[CO2(g)] = ─393.5 kJ/mol
ΔHof[H2O(l)] = ─285.8 kJ/mol
Calculate the enthalpy of formation of 1 mole of octane.
A. ─210 kJ B. ─11,230 kJ C. 22,040 kJ D. ─420 kJ E. 420 kJ - -A
-Glycine C2H5O2N is important for biological energy. The combustion of
glycine is given by the equation,
4C2H5O2N(s) + 9O2(g) 8CO2(g) + 10H2O(l) + 2N2(g) ΔHorxn = ─3857 kJ
Given that ΔHof[CO2(g)] = ─393.5 kJ/mol, and ΔHof[H2O(l)] = ─285.8 kJ/mol.
Calculate the enthalpy of formation ΔHof per mole of glycine.
A. ─537.2 kJ/mol
B. ─268.2 kJ/mol
C. 2149 kJ/mol
D. ─3178 kJ/mol
E. ─964 kJ/mol - -A
-Calculate ΔHorxn for the following reaction.
2H2O2(l) 2H2O(l) + O2(g)
Use the following information:
ΔHof (H2O2(l)) = -187.6 kJ/mol ; ΔHof (H2O(l)) = -285.8 kJ/mol ; ΔHof (O2(g))
= 0 kJ/mol
A. 53.0 kJ B. 98.2 kJ C. -98.2 kJ D. 196.4 kJ E. ─196.4 kJ - -E
-Given 2Al(s) + 3/2O2(g) Al2O3(s) ΔHof = ─1670 kJ
What is ΔH for the reaction?
2Al2O3(s) 4Al(s) + 3O2(g) ΔHorxn = ?
A. 3340 kJ B. 1670 kJ C. ─3340 kJ D. ─1670 kJ E. ─835 kJ - -A
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