Chem practice quiz 3 PDF

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CHM-113 PRACTICE QUIZ 3 CHAPTER 5 Directions: This set of questions are designed to provide the content, style, and level of difficulty of questions encounter on an actual assessment. All responses must be submitted through Mastering Chemistry link for that assignment located in Loudcloud. The questions are not located in Mastering and students must use this document and enter their letter choice for each answer.

1.

Select the incorrect statement. A) B) C) D)

2.

Select the incorrect statement. A) B) C) D)

3.

q is the symbol for heat q = mCsΔT The unit for q is Joules q is positive when the system releases heat

w is positive when work is done on the system w = PΔV The unit for w is Joules w is the symbol for work

What are the signs for q and w if a system absorbs 180 J of heat energy while expanding against constant pressure? A) B) C) D)

+q and -w +q and +w -q and -w -q and +w

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Revised 10/20/2021

4.

What is the change in internal energy of a system that has 682 J of work done on it and gives off 485 J of heat? A) B) C) D)

5.

What is the change in internal energy for a system that performs 213 kJ of work on its surroundings and loses 79 kJ of heat in the process. A) B) C) D)

6.

Heat flows from the system to the surroundings The system does work on the surroundings ΔE = +4 KJ The process is exothermic

Select the endothermic reaction. A) B) C) D)

9.

32.9 kJ 108 kJ 25.5 kJ 7.89 kJ

For a particular process, the system releases 17 kJ of heat and has 21 kJ of work performed on it. Which of the following statements is false? A) B) C) D)

8.

+292 J -292 kJ +152 J -152 J

What is the change in internal energy for a system undergoing an endothermic process in which 29.2 kJ of heat flows and where 3.70 kJ of work is done on the system? A) B) C) D)

7.

+1167 J -1167 J +197 J -197 J

CH4(s) + O2(g)  CO2(g) + 2 H2O(l) + 890 kJ 2 HCl(g) + 185 kJ  H2(g) + 2 Cl2(g) 4 NH3(g) + 5 O2(g)  4 NO (g) + 6 H2O(l) ΔH = -1169 kJ None of the reactions are endothermic

Select the exothermic reaction. A) B) C) D)

4CO(g) + Fe3O4(s) 3Fe(s) + 4CO2(s)  ∆H = +12.5 kJ 4 NH3(g) + 5 O2(g)  4 NO (g) + 6 H2O(l) + 1169 J CO2(g) + 2 H2O(l) + 890 kJ  CH4(s) + O2(g) 2 HCl(g) + 185 kJ  H2(g) + 2 Cl2(g)

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Revised 10/20/2021

10.

Select the correct statement. A) B) C) D)

11.

In the following reaction ΔH° = -3351 kJ is __________, and therefore heat is __________ by the reaction. 4Al (s) + 3O2 (g)  2Al2O3 (s) A) B) C) D)

12.

The reaction is endothermic ΔH = -72.3 kJ ΔH = +72.3 kJ The reaction absorbs heat.

Calculate the work done by a system when a piston expands from a volume of 13.27 L to 76.55 L against a pressure of 14.89 atm? A) B) C) D)

14.

exothermic, released exothermic, absorbed endothermic, released endothermic, absorbed

Given the equation below, which of the following is true? 2 Mg(s) + O2(g)  2 MgO(s) + 72.3 kJ A) B) C) D)

13.

In an exothermic reaction, the surroundings releases heat. If the sign of w is negative, the reaction is always exothermic. If ΔE is negative, the reaction is always exothermic. When the surroundings gains heat, the reaction is exothermic.

-9.545 J -4.250 J -63.28 J -95450 J

Calculate the work done (in J) when a gas condenses from 971 mL to 264 mL at a constant pressure of 4.00 atm. A) B) C) D)

+2.83 J +286 J -2.83 J -286 J

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Revised 10/20/2021

15.

Select the correct statement. A) B) C) D)

16.

Water has a specific heat of 4.184 J/g°C while glass (Pyrex) has a specific heat of 0.780 J/g°C. If 10.0 J of heat is added to 1.00 g of each of these, which will experience the larger increase of temperature? A) B) C) D)

17.

Methanol Ethanol Acetone All substances would behave the same

Select the incorrect statement. A) B) C) D)

19.

glass water they both will experience the same change in temperature since only the amount of a substance relates to the increase in temperature. Not enough information is provided.

Select which of the following substances would require the least amount of energy to increase 20.0 g by 20C.

A) B) C) D) 18.

w and ΔV have the same sign because the gas expands, work flows into the surroundings w and ΔV have the opposite sign because the gas expands, work flows into the surroundings w and ΔV have the same sign because the gas expands, work flows out of the surroundings w and ΔV have the opposite sign because the gas expands, work flows out of the surroundings

Specific heat capacity can never be a negative value. Specific heat capacity of a substance is the amount of energy required to increase the temperature of 1 g of that substance by 1F. Specific heat capacity is a larger value when more energy is required to change the temperature of that substance. More than one statement is incorrect.

The specific heat capacity of lead is 0.13 J/g°C. How much heat (in J) is required to raise the temperature of 15 g of lead from 22°C to 37°C?

A) 29 B) 5.8 x 10-4 Copyright ©2020 Grand Canyon University

Revised 10/20/2021

C) D) 20.

If 1.45 J of heat are added to a 2.00 g sample of aluminum metal and the temperature of the metal increases by 0.798 °C, what is the specific heat of the aluminum? A) B) C) D)

21.

0.418 2.83 3.25 18.0

A chunk of iron at 90.6°C was added to 200.0 g of water at 15.5°C. The specific heat of iron is 0.449 J/g°C, and the specific heat of water is 4.184 J/g°C. The temperature of the resulting mixture was 18.2°C. Assuming no heat was lost to the surroundings, what was the mass of the iron added? A) B) C) D)

24.

2880 g 5.43 x 103 g 54.3. g - 54.3. g

How many Pop TartsTM are needed to convert 1,000.0 g of water at 20.0°C to 100.0°C? One Pop TartTM is equal to 800,000 J of energy. A) B) C) D)

23.

0.579 J/g°C 0.909 J/g°C 1.68 J/g°C 3.63 J/g°C

How many grams of water (4.184 J/gC) can be heated from 20.0 C to 75.0C using 12.5 kJ? A) B) C) D)

22.

-0.13 2.0

468 g 55.5 g 66.9 g 69.5 g

A 24.6 g sample of a metal is heated to 110.0°C and then placed in a coffee cup calorimeter containing 125 g of water at a temperature of 23.00°C. After the metal cools, the final temperature of the metal and water is 24.83°C. Assuming no heat has escaped to the surroundings or been absorbed by the calorimeter, calculate the specific heat of the metal. A) B) C) D)

4.18 J/g°C 0.457 J/g°C 0.499 J/g°C 1.00 J/g°C

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Revised 10/20/2021

25.

The dissociation of a salt in water to from an aqueous solution is called enthalpy of solution, ΔH soln. The ΔHsoln for CaCl2 is -120 kJ/mol. When CaCl2 is added to water _____. A) B) C) D)

the temperature of the water will increase. the temperature of the water will remain the same. the process is endothermic. nothing will occur, CaCl2 is insoluble.

26.

The value of ΔH° for the reaction below is -336 kJ. Calculate the heat (kJ) released to the surroundings when 23.0 g of HCl is formed. CH4 (g) + 3Cl2 (g)  CHCl3 (l) + 3HCl (g) A) 211 B) 177 C) 70.7 D) -336

27.

The heat of combustion for 1.00 mole of carbon to carbon dioxide is -410. kJ. How many kJ of heat would be liberated from the complete combustion of 60.0 g of carbon? A) B) C) D)

28.

The common fertilizer NH4NO3(s), can explosively decompose according to the following reaction. What is the heat released when 80.06 g of NH4NO3(s) explodes? Molar mass of NH4NO3(s) = 80.06 g/mol. 2 NH4NO3(s)  2 N2(g) + O2(g) + 4 H2O (g) ΔH = -236.15 kJ A) B) C) D)

29.

-82.0 kJ -2050 kJ -24,600 kJ -879 kJ

-472.3 kJ -236.15 kJ -118.08 kJ -59.04 kJ

In a popular television series, the two characters use thermite to assist with breaking into a chemical storage facility because the reaction between aluminum and iron(III) oxide produces a tremendous amount of heat. If they began with 10.0 g of Al, how many kJ of heat would be released? 2 Al(s) + Fe2O3(s)  852 kJ + Al2O3(s) + 2 Fe(s) A) B) C) D)

158 kJ 236 kJ 472 kJ None of the above

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Revised 10/20/2021

30.

To which of the following reactions occurring at 25°C does the symbol ΔH°f [H2O(l)] apply? A) B) C) D)

31.

All of the following have standard enthalpy of formation values of zero at 25°C, 1 atm, and 1.0 M concentration except: A) B) C) D)

32.

H2O(l)  2 H(g) + O(g) 2 H(g) + O(g)  H2O(l) H2(l) + ½ O2(g)  H2O(l) H2(g) + ½ O2(g)  H2O(l)

Cl2(g) O2(g) Na(s) All of these have ΔH°f = 0.

Which of the following represents a standard enthalpy of formation reaction? A) B) C) D)

C(s) + O2 (g)  CO2 (g) 2Na (s) + Cl2 (g)  2NaCl (s) MgO (s) + H2O (l)  Mg(OH)2 (s) All of the above are standard enthalpy of formation reactions.

Use the following table for questions 33-36. Substance ΔH°f (kJ/mol) Ca(OH)2(s) -986.6 H3AsO4(aq) -900.4 Ca(H2AsO4)2(aq) -2346.0 H2O(l) -285.9 33.

Substance NH3(g) NO(g) C2H2(g) C2H6(g)

ΔH°f (kJ/mol) -46.19 +90.37 +226.78 -84.68

Given the data in the table below, ΔH°rxn for the following reaction is ______ kJ. Ca(OH)2(s) + 2H3AsO4(aq)  Ca(H2AsO4)2(aq) + 2H2O(l) A) B) C) D)

-4219 -130.4 -4519 -76.4

Use the following table for questions 33-36. Substance ΔH°f (kJ/mol) Ca(OH)2(s) -986.6 H3AsO4(aq) -900.4 Ca(H2AsO4)2(aq) -2346.0 Copyright ©2020 Grand Canyon University

Substance NH3(g) NO(g) C2H2(g)

ΔH°f (kJ/mol) -46.19 +90.37 +226.78 Revised 10/20/2021

H2O(l)

34.

C2H6(g)

Calculate ΔHrxn for A)

35.

-285.9

-1169 kJ

-84.68

4 NH3(g) + 5 O2(g)  4 NO(g) + 6 H2O(l) B)

+1169 kJ

C)

-149.3 kJ

D)

149.3 kJ

Using standard enthalpies of formation, calculate the heat of hydrogenation of acetylene gas, C2H2(g), to form ethane gas. C2H2(g) + 2H2(g)  C2H6(g) A) 142.1 kJ

36.

+966.7 kJ/mol -966.7 kJ/mol -58.1 kJ/mol +58.1 kJ/mol A  2C + E

ΔH1 + ΔH2 + ΔH3 ΔH1 + ΔH2 ΔH1 + ΔH2 - ΔH3 ΔH1 + 2 ΔH2 - ΔH3

Determine the enthalpy of the reaction: 3Fe2O3 (s) + CO (g)  CO2 (g) + 2Fe3O4 (s), given the following reactions. Fe2O3 (s) + 3CO (g)  2Fe (s) + 3CO2 (g) ∆H = -28.0 kJ 3Fe (s) + 4CO2 (s)  4CO (g) + Fe3O4 (s) ∆H = +12.5 kJ A) B) C) D)

39.

D +311.46 kJ

Consider the following numbered processes to calculate ΔH for the process: A  2B ΔH1 B  C + D ΔH2 E  2D ΔH3 A) B) C) D)

38.

C) -142.1 kJ

Calculate the standard enthalpy of formation of solid calcium carbide. CaC2(s) + 2 H2O(1)  Ca(OH)2(s) + C2H2(g) ΔH°rxn = - 129.9 kJ/mol A) B) C) D)

37.

B) -311.46 kJ

40.5 +109 -59.0 -109

Determine the enthalpy of the reaction: N2 (g) + O2 (g)  2NO (g), given the following reactions.

N2 (g) + 2O2 (g)  2NO2 (g) 2NO (g) + O2 (g)  2NO2 (g) Copyright ©2020 Grand Canyon University

ΔH = 66.4 kJ ΔH = -114.2 kJ Revised 10/20/2021

A) B) C) D) 40.

-47.8 47.8 180.6 90.3

Determine the enthalpy of the reaction: S (s) + 3/2 O2 (g)  SO3 (g), given the following reactions. SO2 (g)  S(s) + O2 (g) ΔH = +296.0 kJ 2 SO3 (g)  2 SO2 (g) + O2 (g) ΔH = +198.2 kJ A) B) C) D)

-395.1 kJ 494.2 kJ 97.8 kJ -97.8 kJ

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Revised 10/20/2021...