Energy and Chemical Change

Practice Test
      
  1.In the chemical reaction between aqueous solutions of hydrochloric acid HCl and sodium hydroxide NaOH, what is the chemical system?  
  a.   NaOH and water  
  b.   HCl + NaOH → NaCl + H2O  
  c.   HCl and water  
  d.   aqueous HCl and NaOH  
      
  2.How much heat energy is liberated when 11.0 grams of manganese is used in the formation of Mn2O3?

ΔHf° for Mn2O3 is -962.3 kJ/mol SC.1.4.5		  
  a.   96.3 kJ  
  b.   460 kJ  
  c.   289 kJ  
  d.   192 kJ  
      
  3.Chemical reactions and physical changes that absorb energy from their surroundings are __________.  
  a.   exothermic  
  b.   endothermic  
  c.   isothermic  
  d.   mesothermic  
      
  4.Given the following information,

SO3 g+ H2Ol→H2SO4 l ΔH° = -133 kJ

Pbs+PbO2 s + 2H2SO4l→2PbSO4s+2H2OlΔH° = -509 kJ

calculate theΔH° for the reaction below.

Pbs+PbO2 s+2SO3 g → 2PbSO4 s SC.B.1.4.6		  
  a.   b. -376 kJ  
  b.   -775 kJ  
  c.   376 kJ  
  d.   -642 kJ  
      
  5.Which of the following substances has an enthalpy value of 0 at 298 K and 1 atmosphere of pressure?  
  a.   Nas  
  b.   NaOHs  
  c.   HClaq  
  d.   CO2g  
      
  6.At one atmosphere pressure and the melting point of a substance, which statement is true about this general equation? solid 3 liquid SC.A.1.4.3  
  a.   Both ΔH and ΔS = 0 for the process  
  b.   ΔG = 0 for the process  
  c.   ΔH = 0 for the process  
  d.   ΔS = 0 for the process  
      
  7.Calculate the amount of heat absorbed by 10.0 grams of ice at -15.0°C as it is converted to liquid water at 50.0°C. The specific heat of H2Os = 2.09 J/g·°C. The specific heat of H2Ol = 4.18 J/g·°C. The heat of fusion is 333 J/g. SC.A.1.4.3  
  a.   5.73 kJ  
  b.   2.83 kJ  
  c.   0.676 kJ  
  d.   0.170 kJ  
      
  8.How much heat is required to melt 200 grams of ice? The heat of fusion is 333 J/g. SC.A.1.4.3  
  a.   c. 1.66 J  
  b.   66.6 kJ  
  c.   d. 6.66 kJ  
  d.   666 J  
      
  9.From the following data,

H2 g+Cl2 g → 2HClg ΔH°v = -185 kJ

2H2 g+O2 g → 2H2Og ΔH° = -483.7 kJ

calculateΔH° for the following reaction.

4HClg +O2 g → 2Cl2 g+ 2H2Og		  
  a.   -299 kJ  
  b.   299 kJ  
  c.   114 kJ  
  d.   -114 kJ  
      
  10.Which of the following processes occurs with a decrease in entropy? SC.A.1.4.3  
  a.   sublimation of dry ice  
  b.   freezing of water  
  c.   boiling water  
  d.   dissolving salt in water  
      
  11.A process can never be spontaneous when it is _________. SC.B.2.4.1  
  a.   exothermic, and there is a decrease in disorder  
  b.   endothermic, and there is an increase in disorder  
  c.   endothermic, and there is a decrease in disorder  
  d.   exothermic, and there is an increase in disorder  
      
  12.Calculate the enthalpy for the reaction:

2ZnSs +3O2g → 2ZnO s+ 2SO2g ΔHf° kJ/mol -206.0 0 -348.3–296.8 SC.B.1.4.1		  
  a.   -270.6 kJ  
  b.   +878.2 kJ  
  c.   +270.6 kJ  
  d.   -878.2 kJ  
      
  13.How much heat is absorbed in the complete reaction of 3.00 grams of SiO2 with excess carbon in the reaction below? ΔH° for the reaction is +624.7 kJ.

SiO2g+ 3Cs → SiCs+2COg SC.A.1.4.5		  
  a.   31.2 kJ  
  b.   366 kJ  
  c.   1.13 ´ 105 kJ  
  d.   5.06 kJ  
      
  14.Calculate the ΔG° for the reaction:

2C2H2g+5O2g→ 4CO2g+2H2OlΔG° kJ/mol209.2, 0, -394.4, -237.2 SC.B.2.4.7		  
  a.   -2599 kJ  
  b.   -2470 kJ  
  c.   -1409 kJ  
  d.   -1643 kJ  
      
  15.If 5.0 grams of copper cools from 35.0°C to 22.6°C and loses 23.6 joules of heat, what is the specific heat of copper?  
  a.   3.8 ´ 102 J/g·°C  
  b.   0.62 J/g·°C  
  c.   0.076 J/g·°C  
  d.   0.38 J/g·°C  
      
  16.Calculate ΔH° for the following reaction.

Fe3O4s+COg → 3FeOs+CO2g ΔHf°kJ/mol-1118-110.5-272-393.5 SC.B.2.4.1		  
  a.   54 kJ  
  b.   neg. 50 kJ  
  c.   -263 kJ  
  d.   19 kJ  
      
  17.One calorie is equal to 4.184J. How much energy in joules is supplied by a breakfast bar containing 170 nutritional calories?  
  a.   711 J  
  b.   170 J  
  c.   7.11 x 105 J  
  d.   1.7 x 105 J  
      
  18.A body in motion possesses kinetic energy because of its __________. SC.B.1.4.3  
  a.   position  
  b.   inertia  
  c.   composition  
  d.   motion  
      
  19.The temperature of a 2.5 kg sample of silver was heated from 25°C to 45°C. How much energy was absorbed by the silver?

Specific Heats of Common Substances at 298 K 25°C
Specific heat


Substance J/g•°C
Waterl

liquid
4.184
Waters

ice
2.03
Waterg

steam
2.01
Ethanoll

grain alcohol
2.44
Aluminums
0.897
Granites
0.803
Irons
0.449
Leads
0.129
Silvers
0.235
Golds
0.129


SC.B.1.4.6		  
  a.   1.2 x 104 J  
  b.   12 J  
  c.   2.6 x 104 J  
  d.   118 J  
      
  20.The temperature of a 25.0 g sample of aluminum changed from 25°C to37°C when heated. How much energy was absorbed by the aluminum?

Specific Heats of Common Substances at 298 K 25°C
Specific heat


Substance J/g•°C
Waterl

liquid
4.184
Waters

ice
2.03
Waterg

steam
2.01
Ethanoll

grain alcohol
2.44
Aluminums
0.897
Granites
0.803
Irons
0.449
Leads
0.129
Silvers
0.235
Golds
0.129


SC.B.1.4.6		  
  a.   269 J  
  b.   22.4 J  
  c.   334 J  
  d.   10.8 J  
      
  21.How much heat is evolved when 27.0 g of glucose is burned according to this equation?

C6H12O6 + 6O2 → 6CO2+ 6H2O; Δ H comb. = -2808kJ

Specific Heats of Common Substances at 298 K 25°C
Substance
Specific heat

J/g·°C
Waterl

liquid
4.184
Waters

ice
2.03
Waterg

steam
2.01
Ethanoll

grain alcohol
2.44
Aluminums
0.897
Granites
0.803
Irons
0.449
Leads
0.129
Silvers
0.235
Golds
0.129


SC.B.1.4.6		  
  a.   136 kJ  
  b.   421 kJ  
  c.   421 J  
  d.   280 kJ  

 
   
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