Quiz 2

Question 1

NH₄Cl is a

Answer 1

Salt

Question 2

Which one of these compounds is insoluble in water?

A- BaSO₄

B- NaCL

C- KI

D- HCl

E- No correct answer is given

Answer 2

A

Question 3

Identify a Strong Base

A- HNO₃

B- KCl

C- NH₄OH

D- NaOH

E-Na₂SO₄

Answer 3

D

Question 4

Hydrogen gas reacts with oxygen gas to form water vapor. If 34.5 g of hydrogen gas react with 26.6 g of oxygen gas, how many grams of water vapor will be produced? (Hint: two reactants, two quantities => limiting reactant problem).

2H_2(g) + O_2(g) -> 2H₂O_(g)

Answer 4

30.0 g H₂O

Question 5

Hydrogen gas reacts with excess nitrogen gas to form ammonia gas (NH₃). If 10.2 g of hydrogen gas react with excess of nitrogen gas, how many grams of ammonia gas will be produced? (Hint: one reactant is excess!).

Answer 5

57.4 g NH₃

Question 6

Acid-base reaction is a neutralization reaction. If 12.50 mL of 1.20 M NaOH solution is used to neutralize 45.25 mL of HNO₃ solution, calculate the concentration of the original HNO₃ solution.

Answer 6

0.331 M

Question 7

Acid-base reaction is a neutralization reaction. If 12.50 mL of 1.20 M NaOH solution is used to neutralize 45.25 mL of H2SO₄ solution, calculate the concentration of the original H2SO₄ solution.

NaOH + H₂SO₄ -> 2H₂O (not balanced)

Answer 7

0.166 M

Question 8

(T/F)

Oxidation-reduction (redox) reactions involve electrons. If an element in ground state loses two electros during the redox reaction, this process si called oxidation.

Answer 8

True

Question 9

What is the oxidation number of P in H₃PO₄?

Answer 9

P= +5

Question 10

What is the oxidation number of P in PO₄^3-?

Answer 10

P= +5

Question 11

Which of the following molecule is an electrolyte?

A- Pure Water

B- Sugar Solution

C- Pure butanol

D- KCl solution

E- More than one answer is given

Answer 11

D

Question 12

The reaction of 22.5 of Fe with excess of oxygen gas produced 24.2 g of Fe₂O₃. Calculate the percent yeld. (hint: one reactant, O₂, is excess, so the Fe is the limiting reactant)

Answer 12

75.2%

Question 13

Milk of magnesia contains magnesium hydroxide. What mass of Mg(OH)₂ is needed to prepare 500.00 mL of 0.0500 M solution of magnesium hydroxide?

Answer 13

1.46 g of Mg(OH)₂

Question 14

What element is oxidized in the following reaction?

2Li + O₂ -> Li₂O

A- Li

B- O₂

C- more than one correct answer is given

D- no correct answer is given

Answer 14

A

Question 15

Identify/ predict the products of the reaction between Na₂SO₄ and BaCl₂ solutions. (SOLUBILITY RULES)

Answer 15

NaCl + BaSO₄

Question 16

Write the complete molecular equation for the reaction between Na₂SO₄ and BaCl₂ solutions.

Answer 16

2NaCl_(aq) + BaSO_4(s)

Question 17

Write the complete ionic equation for the reaction between Na₂SO₄ and BaCl₂ solutions

Answer 17

2Na⁺_(aq) + SO₄^2-_(aq) + Ba²⁺_(aq) + 2Cl^-_(aq) -> 2 Na⁺_(aq) + 2Cl^-_(aq) + BaSO_4(s)

Question 18

Write the net ionic equation for the reaction between Na₂SO₄ and BaCl₂ Solutions

Answer 18

SO₄^2-_(aq) + Ba²⁺_(aq) -> BaSO_4(s)

Question 19

Identify the driving force(s) in the reaction between Na₂SO₄ and BaCl₂

Answer 19

Formation fo a precipitate (ppt) BaSO_4(s)

Question 20

How many moles in 24.02 fo CO₂?

Answer 20

0.5458 mol CO₂

Question 21

How many grams in 8.79 moles of CH₄?

Answer 21

141 g

Question 22

In the following reaction, how many grams of sodium sulfate are needed to react with 3.08 moles of strontium nitrate? (hint: stoichimoetry Na₂SO₄: Sr(NO₃)₂ = 1:1)

Sr(NO₃)₂ + Na₂SO₄ -> SrSO₄ + 2 NaNO₃ (balanced)

Answer 22

437 g Na₂SO₄

Question 23

If 10.89 g of silver are recovered when 42.88 g of zinc and 29.50 g of silver nitrate are reacted, calculate the precent yield? (hint: limiting reactant problem; the euqation is balanced for you.)

Zn + 2AgNO₃ -> An(NO₃)₂ + 2Ag (balanced)

Answer 23

58.14%

Question 24

Strong electrolytes are…

A- Always Salts

B- always acids

C- always bases

D- always ionic compounds

E- no correct answer given

Answer 24

E

Question 25

Which is of the followign is the net ionic equation for Pb(NO₃)₂ + 2NaI -\> 2NaNO₃ + PbI₂ (Balanced?) A-Pb(NO₃)₂ +2NaI -\> 2 NaNO₃ +PbI₂ B- Pb²⁺ + 2 I^- -\> PbI₂ C-Pb²⁺ + 2 I^- -\> 2PbI₂ D- NO₃^- + Na⁺ -\> NaNO₃ E- No correct answer given

Answer 25

B

Question 26

What is the driving force in the reaction HCl + NaOH -\> NaCl + H₂O

Answer 26

Formation of a nonelectrolyte

Question 27

(T/F) PbI₂ cannot be used as an electrolyte

Answer 27

True

Question 28

(T/F) At room temperature a sample that has a weak intermolecular attractions is most likely to be a gas.

Answer 28

True

Question 29

What volume is occupied by 0.550 moles of as at 1.00 atm and 313 K?

Answer 29

V= 14.1 L

Question 30

What volume will 0.245 moles of gas occupy at 98.2°F and 755 mmHg?

Answer 30

V= 6.28 L

Question 31

What is the pressure of a sample of gas after it is compressed from 2.00 L, 2.00 atm to 0.250 L at a constant temperature?

Answer 31

Pressure= 16.0 atm

Question 32

What is the temperature of a sample of gas after it is allowed to expand from 1.50 L, 6.00 atm and 293 K to 5.60 L and 0.180 atm?

Answer 32

Temperature = 33.0 K

Question 33

What is the temperature of 10.45 moles of a gas in a 4.00 L cylinder at 2.50 atm?

Answer 33

Temperature- 11.7 K

Question 34

A 4.50 L gas cylinder contains 1.50 g of O₂ and 4.30 g of N₂. What is the pressure in the cylinder at 22.00°C?

Answer 34

Pressure= 1.08 atm

Question 35

How many grams of Cl₂ are in a 25.0 L cylinder at 250.0 torr and 293 K?

Answer 35

24.2 g Cl₂

Question 36

(T/F) At STP, the pressure is 1.00 atm and the temperature is 273°C

Answer 36

False

Question 37

Which of these statements is true about gases? A- Gas molecules are in constant motion except at 0 K B- gas molecules interact very well C- Gases exert little pressure D- Gas molecules are large compared to the distances between them E- Temperature does not affect the rate of motion of gas molecules

Answer 37

A

Question 38

A pressure of 475. mm Hg has what value measured in atmospheres?

Answer 38

0.625 atm

Question 39

Inflate a 2.50 liter ballon in a place where the atmospheric pressure is 715. torr. What will the volume of the ballon be in a place where the atmospheric pressure is 760. torr?

Answer 39

Volume = 2.35 L

Question 40

(T/F) Kinetic energy is the energy of motion and change

Answer 40

true

Question 41

If a sample of 0.50 moles of He occupies 4.2 L under certain conditions, what volume will 0.23 moles occupy under the same conditions?

Answer 41

volume = 1.9 L

Question 42

What is the volume of 2.75 g of H₂ gas at 4.75 atm and 315 K?

Answer 42

Volume = 7.43 L

Question 43

A 0.465 g sample of an unkown compound occupies 0.245 L at 298 K and 17.9 psi. What is the molar mass of the unknown compound?

Answer 43

38.06 g/mol

Question 44

A mixture of 5.00 g of He and 5.00 g of Ne have a total pressure of 2.50 atm. What is the partial pressure of He?

Answer 44

2.08 atm

Question 45

Calculate the root mean square velocity of hydrogen molecules at 22.00°C. Urms= (3RT/M)^1/2 R= 8.314 J/mol. K

Answer 45

Urms= 1911 m/s

Question 46

One of the following equation/law is used to calculate the properties of a gas under non-ideal conditions. A- Dalton's law B- Charle's Law C- Boyle's Law D- van der Waals equation E- Avagodro's law

Answer 46

D

Question 47

The atmospheric pressure is 720. mmHg. What is the pressure in inches of Hg (inHg)?

Answer 47

28.3 inHg

Question 48

Which of the following samples has the greatest density at STP? A- SF₆ B- NO C- He D- CO₂ E- All of these marterials have the same density at STP

Answer 48

A

Question 49

A mixture of 0.152 moles of NO, 0.245 moles of H₂ and 0.993 moles of Ar has a total pressure of 5.75 atm. Calculate the partial pressure of Ar

Answer 49

4.11 atm

Question 50

Calcium hydride (CaH₂) reacts with water to form hydrogen gas, according to the following reaction. CaH_2(S) + 2H₂O_(l) -\> Ca(OH)_2(aq) + 2H_2(g) How many grams of calcium hydride (CaH₂) are needed to generate 2.50 L of hydrogen gas at a pressure of 0.900 atm and a temperature of 38.20°C?

Answer 50

1.85 g CaH₂

Question 51

Consider the following combustion reaction: C₂H_4(g) + O_2(g) -\> CO_2(g) +H₂O_(g) (not balanced) determine the number of liters of CO₂ gas formed at STP when 2.45 grams of C₂H_4(g) is burned with excess oxygen.

Answer 51

3.91 L

Question 52

(T/F) A non-electrolyte is a substance, when dissolved in water, can conduct electricity.

Answer 52

False

Question 53

What might happen when calcium nitrate [Ca(NO₃)₂] solution is mixed with a potassium phophate (K₃PO₄) solution.

Answer 53

formation of an insoluble solid, Ca₃(PO₄)_2(s)

Question 54

How many grams of potassium dichromate (K₂Cr₂O₇) are required to prepare a 500.00 mL solution with a concentration of 1.50 M? (MM of K₂Cr₂O₇ is 294.2 g/mol)

Answer 54

221 g

Question 55

In a titration experiment a student found that 25.55 mL of 1.00 M KOH solution are required to neutralize 37.75 ml of sulfuric acid (H₂SO₄) What is the concentration of H₂SO₄ solution (Hint: write the balanced equation)

Answer 55

0.338 M

Question 56

Which of the following gas will have the greatest volume at STP? A- 2.5 g N₂ B- 2.5 g O₂ C- 2.5 g Ar D- 2.5 g NO E- 2.5 g CO₂

Answer 56

A

Question 57

The volume of a gas is proporational to number of moles of gas at constant pressure and constant temperature is known as....

Answer 57

Avogadro's law

Question 58

How many grams of KCl_(s) are produced from the decomposition of KClO_3(s) which produces 125.0 L fo O_2(g) at 34.5°C and 1.22 atm pressure?

Answer 58

0.300 g KCl

Question 59

How much energy is needed to warm 25.0 g of benzene from 1.00°C to 8.00°C? (Csp of benzene can be found in the CRC handbook fo chemistry and physics- Library website)

Answer 59

265 J

Question 60

The production of 1.00 g of C₂H₂ gas from graphite and H₂ gas requires 8.7033 kJ under standard conditions. What is the (delta)H°_f(C2H2)? 2 C_(graphite) + H_2(g) -\> C₂H_2(g)

Answer 60

226.6 kJ/mol

Question 61

How much energy will warm 10.0 g of gold if the (delta)T= 4.1°C?

Answer 61

5.25 J

Question 62

How many joules need to be added to 4.50 g of graphite to raise its temperature by 25 K? (Csp of graphite can be found in teh CRC handbook of chemistry and physics- library website)

Answer 62

81 J

Question 63

What is the heat of reaction for the reaction 2Fe_(s) + O_{3 (g)} -\> Fe₂O₃

Answer 63

-966.9 kJ/mol

Question 64

What is the specific heat of a material if 45.0 J are needed to warm a 2.25 g sample of 0.0°C to 22.0°C?

Answer 64

0.909 J/g°C

Question 65

(T/F) thermal energy is a form of chemical energy

Answer 65

False

Question 66

(T/F) An open system is one that can gain (or lose) matter and energy

Answer 66

True

Question 67

How much heat (in kJ) is transferred from surroundings to warm 100.0g of water from 5.0°C to 22.0°C?

Answer 67

7.11 kJ

Question 68

A 5.5 g block of Cu at 95.0°C is placed in 100.0 ml of water at 22.5°C. What is the final temperature of the water. (Hint- this problem involves transfer of heat energy.) (D= 1.00 g/mL)

Answer 68

22.9°C

Question 69

what is (delta)H°_reaction for 2SO_2(s) + O₂ -\> 2 SO_3(g) (delta) H°_f SO₃= -395.7 kJ/mol (delta) H°_f SO₂ = -296.8 kJ/mol (delta) H°_f O_2(g) = O kJ/mol

Answer 69

-197.8 kJ/mol

Question 70

Which one is true based on the following reaction? CH_4(g) + 2O_2(g) -\> CO_2(g) + 2H₂O_(g) (delta)H°_rxn = -802.3 kJ A- this is an endothermic reaction B- this is an exothermic reaction C- the products have more potential energy D- the reactants have more potential energy E- more than one correct answer is given

Answer 70

E B/D are correct

Question 71

(T/F) in exothermic reactions, the products of the reaction have more potential energy than the reactants

Answer 71

False

Question 72

Which of the following signs on q and w represent a system that is doing work on the surroundings, as well as gaining heat from the surroundings? A- q= +, w= - B- q= -, w=+ C- q=+, W=+ D- q= -, w= - E- non of these represent the system referenced above

Answer 72

A

Question 73

Use the (delta)H°_f and (delta)H°_rxn information provided to calculate (delta)H°_f for HCl_(g) CH_4(g) + 4Cl_2(g) -\> CCl_4(g) + 4HCl_(g) (delta) H°_rxn = -389 kJ (delta) H°_f of CH_4(g) = -75 kJ/mol (delta) H°_f of CCl_4(g) = -96 kJ/mol

Answer 73

-92 kJ/mol

Question 74

Calculate the change internal energy (deltaE) for a system that is giving off 45.0 kJ of heat and is performing 895 J of work on the surroundings

Answer 74

-45.9 kJ

Question 75

(T/F) Heat capacity: The quantity of heat required to change a system's temperature by 1°C

Answer 75

True

Question 76

(T/F) Specific heat capacity: The quantity of heat required to raise the temperature of 1 gram of a substance by 1°C (Hint: consider analyzing the units of C_s)

Answer 76

True

Question 77

A 4.00 g sample of water at 22.5°C is heated by the addition of 98.0 J of energy. The final temperature of the water is \_\_\_°C (the specific heat capacity of water is 4.18 J/g°C)

Answer 77

28.4°C

Question 78

When 0.500 g of cyclohexane (C₆H₁₂) is combusted in a bomb calorimeter that has a water sheath containing 750.0 g of water, the temperature of the water increased by 5.5°C. Assuming that the specific heat of water is 4.18 J/g°C, and that the heat absorption by the calorimeter is negligible, calculate the enthalpy of combustion per mole of cyclohexane.

Answer 78

2.90 \* 10⁶ J/mol

Question 79

# Choose the reaction that illustrates (delta)H°_f for Ca(NO₃)₂ A- Ca_(s) + N_2(g) + 3O_2(g) -\> Ca(NO₃)_2(s) B- Ca⁺_(aq) + NO₃^-_(aq) -\> Ca(NO₃)_2(s) C-Ca⁺_(aq) + NO_3(aq) -\> Ca(NO₃)_2(s) D- Ca_(s) + N_2(g) + O_2(g) -\> Ca(NO₃)_2(s) E- 2Ca_(s) + 2N_2(g) +3O_2(g) -\> Ca(NO₃)_2(s)

Answer 79

A

Question 80

Identify a green-house gas A- O_3(g) B- C₂H_4(g) C- CO_2(g) D- H₂O_(g) E- More than one correct answer is given

Answer 80

E A, C, D are all correct

Question 81

(T/F) The temperature of pressure for the standard state for a _liquid_ are 298 K and 1 atm

Answer 81

true

Question 82

Give teh equation with the elements Na₂SO₄ in their standard state as the reactants and Na₂SO₄ as the product.

Answer 82

2Na_(s) + 1/8S_{8(s, rhombic)} +2O_2(g) -\> Na₂SO₄