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Practice Exam 2 Question List

1. Identify the major ionic species present in an aqueous solution of NH4ClO4.  A) NH4+, Cl-, 4O2 B) N3-, 4H+, Cl-, 4O2 C) 4NH+, 4ClO- D) NH4+, ClO4- E) NH4Cl+, O4-

2. What volume of concentrated nitric acid (15.0 M) is required to make 100. mL of a 3.0 M nitric acid solution by dilution?  A) 20. mL B) 30. mL C) 40. mL D) 50. mL

3. How many total moles of ions are released when 5 moles of Na3PO4 are dissolved in water?

A) 5 moles B) 10 moles C) 20 moles D) 8 moles E) 4 moles

4. What is the new concentration if 400mL of 0.346M NaCl is diluted to a total volume of 750mL?

A) 0.260M B) 0.138M C) 18.5M D) 0.531M E) 0.185M

5. How much 0.54 M NaCl can be prepared via the dilution of 100. mL of a 6.0M NaCl solution?

A) 1.1 L B) 910 mL C) 90 mL D) 540 mL E) 1.9 L

6. Calculate the mass of NaHCO3 needed to prepare 250 mL of 0.024 M NaHCO3 (molar mass = 84 g/mole).

A) 0.50g B) 500g C) 21g D) 880g E) 0.12g

7. Calculate the mass of H2(g) (in grams) that will be formed when 275 mL of 0.725 M HCl solution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride according to the following balanced equation: 2 HCl (aq) + Mg(s) H2(g) + MgCl2(aq)

8. A standard solution of a 0.235 M NaOH solution was used to determine the concentration of an HCl solution. If 22.36 mL of NaOH is needed to neutralize 15.00 mL of the acid, what is the concentration of the acid (in units of molarity)?

A) 5.25M B) 7.88 M C) 2.24M D) 0.35M E) 5.25 x 10-3M

9. The spectator ions in the reaction between aqueous solutions of Ba(NO3)2 and Na2SO4 are

A) NO3 & SO42 B) Ba2+, NO3, Na+, & SO42 C) Na+ & NO3 D) Ba2+ & SO42

E) no spectator ions

10.	Select the compound that is reduced in the following equation: KMnO4 + HCl MnCl2 + Cl2 + H2O + KCl
A)	KMnO4	D)	H2O
B)	HCl	E)	Cl2
C)	MnCl2
11.	Calculate the oxidation number of chromium in Na2Cr2O7.
A)	–2
B)	+2
C)	+6
D)	+12
E)	+14

12	Select the classification for the following reaction. CH4(g) + O2(g)  CO2(g) + 2 H2O(l)
A)	combination	D)	acid-base
B)	decomposition	E)	combustion
C)	displacement

13. A system delivers 225 J of heat to the surroundings while delivering 645 J of work. Calculate the change in the internal energy, E, of the system.

A) –420 J B) 420 J C) –870 J D) 870 J E) –225 J

14. What is the chemical equation for the standard enthalpy of formation for SeOCl2(l)?

A) Se(s) + 2 O(g) + 2 Cl(g) SeOCl2(l)

B) Se(s) + ½ O2(g) + Cl2(g) SeOCl2(l)

C) 2 Se(s) + O2(g) + Cl2(g) 2 SeOCl2(l)

15. A kid bumped their head and needed an ice pack – “boo boo bunny”. Assume the “boo boo bunny” weighs 5g and the initial temperature was 0°C. If “boo boo bunny” absorbed 420 J of energy from the kid’s head, what was the final temperature of the “boo boo bunny”? Specific heat capacity of “boo boo bunny” is 0.85 J/(gx°C).

A) 98.8°C B) -98.8°C C) -71.4°C D) -10.1°C E) 71.4°C

16.	A system that does no work but which receives heat from the surroundings has
A)	q < 0, E > 0.	D)	q = –E.
B)	q > 0, E < 0.	E)	w = E.
C)	q = E.

17.	In which one of the following situations would you expect H to be similar or equal to E?
A)	A reaction that doesn’t involve gases
B)	A reaction in which you have three moles of gas as reactants and two moles of gas as products
C)	A reaction in which the reactants are solids but a gas is created as a product

18. What volume of 0.25M nitric acid (HNO3) is needed to neutralize 3.70 grams of Ca(OH)2 (74 g/mole) according to the following equation: 2 HNO3 + Ca(OH)2 Ca(NO3)2 + 2H2O

A) 99.9 mL B) 400 mL C) 200 mL D) 25.0 mL E) 164 mL

19. The spectator ions in the reaction between aqueous solutions of ZnSO4(aq) and Na2S(aq) are

A) S2 & SO42 B) Zn2+, SO42, Na+, & S2 C) Na+ & SO42 D) Zn2+ & S2 E) no spectator ions

20. Which of the following is insoluble (would be a precipítate)?

A) NaCl B) MgCO3 C) Al(NO3)3 D) K2S E) NaOH

21.	Select the oxidizing agent in the following equation: 2 Al + Fe2O3 Al2O3 + 2 Fe
A)	Al2O3	D)	Fe2O3
B)	Fe	E)	This is not a REDOX reaction
C)	Al
22.	Calculate the oxidation number of sulfur (S) in S2O62-.
A)	+7
B)	-6
C)	-2
D)	+5
E)	+10

23.	Select the classification for the following reaction. 2 AgNO3 + Ni  Ni(NO3)2 + 2 Ag
A)	combination	D)	acid-base
B)	double displacement	E)	combustion
C)	single displacement

24. The specific heat of nickel is 0.444 J/(g °C). If 85.0 J of heat are added to a 50.0 gram piece of nickel at an initial temperature of 22°C, what is the final temperature of the nickel?

A) 18.2°C B) 29.1°C C) 31.8°C D) 25.8°C E) 3.8°C

25. A system has 682 J of work done on it and also releases 485 J of heat. Calculate the change in the energy, Δ E, of the system.

A) –682 J B) +682 J C) +1167 J D) -197 J E) +197 J

26. Given the following equation showing the formation of H2O (18 g/mole), how much heat is involved in decomposing 12.5 grams of H2O into hydrogen and oxygen gas.

2 H2(g) + O2(g) 2H2O(l) ΔH°rxn = -571.6

A) +571.6 kJ B) +285.8 kJ C) +198 kJ D) +396 kJ E) -496 kJ

27. Which of the following will occur when a solution of Pb(NO3)2(aq) is mixed with a solution of KI(aq)?  A) A precipitate of KNO3 will form; Pb2+ and I– are spectator ions. B) No precipitate will form. C) A precipitate of PbI2 will form; K+ and NO3– are spectator ions. D) A precipitate of Pb(NO3)2 will form; K+ and I– are spectator ions. E) A precipitate of PbI2 will form; Pb2+ and I– are spectator ions.

28. What volume (mL) of a 0.3428 M HCl(aq) solution is required to completely neutralize 23.55 mL of a 0.2350 M Ba(OH)2(aq) solution? 

Balanced equation: 2 HCl (aq) + Ba(OH)2(aq) 2 H2O (l) + BaCl2 (aq) A) 55.34 mL B) 11.07 mL C) 16.14 mL D) 32.29 mL E) 47.10 mL

29. For the perchlorate ion ClO4- , what are the oxidation states of the Cl and O, respectively?  A) – 1, – 2 B) +8, – 2 C) +7, – 2 D) +6, – 2 E) +2, – 1

30. Identify the oxidizing agent in the following chemical reaction. Cd + NiO2 + 2H2O Cd(OH)2 + Ni(OH)2  A) Cd B) NiO2 C) H2O D) Cd(OH)2 E) Ni(OH)2

31. Using the activity series given, predict the products of the following single replacement reaction. Cu(s) + Fe2+(aq)   A) Fe(s) + Cu2+(aq) B) CuFe(s) + H2O(l) C) FeCu(s) + H2O(l) D) Fe2+(aq) + Cu2+(aq) E) No reaction occurs

32. A system releases 455 J of heat to the surroundings while doing 345 J of work on the surroundings. What is the change in energy (E) of this system.

A) 800 J

B) 110 J

C) -110 J

D) -800 J

33. For which of these reactions will H and E be approximately the same?

A) 2H2O2(l) 2H2O(l) + O2(g)

B) NO(g) + O3(g) NO2(g) + O2(g)

C) 2 C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(l)

D) P4(s) + 10Cl2(g) 4PCl5(s)

E) N2(g) + 3H2(g) 2NH3(g)

34. Given the specific heat for aluminum is 0.900 J/g·C, how much heat is released when a 3.8 g sample of Al cools from 450.0C to 25C?  A) 54 J B) 60 J C) 86 J D) 1.5 kJ E) 1.7 kJ

35. How many grams of C4H10(g) (58.12 g/mole) must be burned with excess O2(g) in order to release 1.00x104 kJ of heat? Use the balanced thermochemical equation below: 2C4H10 (g) + 13 O2(g) 8 CO2(g) +10 H2O(l) Hrxn = – 5314 kJ/mol,

A) 30.9 g B) 61.8 g C) 109 g D) 153 g E) 219 g

36. Predict the products and write a balanced molecular, total, and net ionic reaction equation for the following situation. (be sure to include charges and states of matter):

NaOH(aq) + Fe(NO3)2(aq)

37. A 28.5 gram sample of iron is heated to 95°C and then dropped into 58 grams of water in a coffee-cup calorimeter. The temperature of the water rises from 23.5°C to 27.1°C. Calculate the specific heat of iron.

38. Hot pyrex (450. grams) is placed in 175.0 grams of water (d = 1.00 g/mL) which was at 21.0°

C. What was the initial temperature of the pyrex (in °C) if the final temperature of the water and pyrex together was 31 °C?

Given: specific heat capacity of pyrex = 0.753 J(gxK)

specific heat capacity of water = 4.18 J(gxK)

39. Consider: 2Al(s) + 3NiCl2(aq) 2AlCl3(aq) + 3Ni(s)

How many grams of excess reactant do you have if you react 22.1 grams of Al with 575 mL of a 1.70 M NiCl2 solution?

Molar masses:

· Al = 26.982 g/mole

· NiCl2 = 129.599 g/mole

· AlCl3 = 133.341 g/mole

· Ni = 58.693 g/mole

40. Consider Cu(s) + 2AgNO3(aq) Cu(NO3)2(aq) + 2Ag(s)

How many grams of excess reactant do you have if you react 155 grams of Cu with 404 mL of 4.7M AgNO3 solution?

Molar masses:

Cu = 63.546 g/mole

AgNO3 = 169.87 g/mole

Cu(NO3)2 = 187.56 g/mole

Ag = 107.868 g/mole