Quiz 2 Flashcards
NH4Cl is a
Salt
Which one of these compounds is insoluble in water?
A- BaSO4
B- NaCL
C- KI
D- HCl
E- No correct answer is given
A
Identify a Strong Base
A- HNO3
B- KCl
C- NH4OH
D- NaOH
E-Na2SO4
D
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).
2H2(g) + O2(g) -> 2H2O(g)
30.0 g H2O
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!).
57.4 g NH3
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.
0.331 M
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)
0.166 M
(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.
True
What is the oxidation number of P in H3PO4?
P= +5
What is the oxidation number of P in PO43-?
P= +5
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
D
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)
75.2%
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?
1.46 g of Mg(OH)2
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
A
Identify/ predict the products of the reaction between Na2SO4 and BaCl2 solutions. (SOLUBILITY RULES)
NaCl + BaSO4
Write the complete molecular equation for the reaction between Na2SO4 and BaCl2 solutions.
2NaCl(aq) + BaSO4(s)
Write the complete ionic equation for the reaction between Na2SO4 and BaCl2 solutions
2Na+(aq) + SO42-(aq) + Ba2+(aq) + 2Cl-(aq) -> 2 Na+(aq) + 2Cl-(aq) + BaSO4(s)
Write the net ionic equation for the reaction between Na2SO4 and BaCl2 Solutions
SO42-(aq) + Ba2+(aq) -> BaSO4(s)
Identify the driving force(s) in the reaction between Na2SO4 and BaCl2
Formation fo a precipitate (ppt) BaSO4(s)
How many moles in 24.02 fo CO2?
0.5458 mol CO2
How many grams in 8.79 moles of CH4?
141 g
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)
437 g Na2SO4
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)
58.14%
Strong electrolytes are…
A- Always Salts
B- always acids
C- always bases
D- always ionic compounds
E- no correct answer given
E
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
B
What is the driving force in the reaction
HCl + NaOH -> NaCl + H2O
Formation of a nonelectrolyte
(T/F)
PbI2 cannot be used as an electrolyte
True
(T/F)
At room temperature a sample that has a weak intermolecular attractions is most likely to be a gas.
True
What volume is occupied by 0.550 moles of as at 1.00 atm and 313 K?
V= 14.1 L
What volume will 0.245 moles of gas occupy at 98.2°F and 755 mmHg?
V= 6.28 L
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?
Pressure= 16.0 atm
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?
Temperature = 33.0 K
What is the temperature of 10.45 moles of a gas in a 4.00 L cylinder at 2.50 atm?
Temperature- 11.7 K
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?
Pressure= 1.08 atm
How many grams of Cl2 are in a 25.0 L cylinder at 250.0 torr and 293 K?
24.2 g Cl2
(T/F)
At STP, the pressure is 1.00 atm and the temperature is 273°C
False
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
A
A pressure of 475. mm Hg has what value measured in atmospheres?
0.625 atm
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?
Volume = 2.35 L
(T/F)
Kinetic energy is the energy of motion and change
true
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?
volume = 1.9 L
What is the volume of 2.75 g of H2 gas at 4.75 atm and 315 K?
Volume = 7.43 L
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?
38.06 g/mol
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?
2.08 atm
Calculate the root mean square velocity of hydrogen molecules at 22.00°C.
Urms= (3RT/M)1/2
R= 8.314 J/mol. K
Urms= 1911 m/s
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
D
The atmospheric pressure is 720. mmHg. What is the pressure in inches of Hg (inHg)?
28.3 inHg
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
A
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
4.11 atm
Calcium hydride (CaH2) reacts with water to form hydrogen gas, according to the following reaction.
CaH2(S) + 2H2O(l) -> Ca(OH)2(aq) + 2H2(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?
1.85 g CaH2
Consider the following combustion reaction:
C2H4(g) + O2(g) -> CO2(g) +H2O(g) (not balanced)
determine the number of liters of CO2 gas formed at STP when 2.45 grams of C2H4(g) is burned with excess oxygen.
3.91 L
(T/F)
A non-electrolyte is a substance, when dissolved in water, can conduct electricity.
False
What might happen when calcium nitrate [Ca(NO3)2] solution is mixed with a potassium phophate (K3PO4) solution.
formation of an insoluble solid, Ca3(PO4)2(s)
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)
221 g
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)
0.338 M
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
A
The volume of a gas is proporational to number of moles of gas at constant pressure and constant temperature is known as….
Avogadro’s law
How many grams of KCl(s) are produced from the decomposition of KClO3(s) which produces 125.0 L fo O2(g) at 34.5°C and 1.22 atm pressure?
0.300 g KCl
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)
265 J
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) + H2(g) -> C2H2(g)
226.6 kJ/mol
How much energy will warm 10.0 g of gold if the (delta)T= 4.1°C?
5.25 J
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)
81 J
What is the heat of reaction for the reaction
2Fe(s) + O3 (g) -> Fe2O3
-966.9 kJ/mol
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?
0.909 J/g°C
(T/F)
thermal energy is a form of chemical energy
False
(T/F)
An open system is one that can gain (or lose) matter and energy
True
How much heat (in kJ) is transferred from surroundings to warm 100.0g of water from 5.0°C to 22.0°C?
7.11 kJ
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)
22.9°C
what is (delta)H°reaction for 2SO2(s) + O2 -> 2 SO3(g)
(delta) H°f SO3= -395.7 kJ/mol
(delta) H°f SO2 = -296.8 kJ/mol
(delta) H°f O2(g) = O kJ/mol
-197.8 kJ/mol
Which one is true based on the following reaction?
CH4(g) + 2O2(g) -> CO2(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
E
B/D are correct
(T/F)
in exothermic reactions, the products of the reaction have more potential energy than the reactants
False
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
A
Use the (delta)H°f and (delta)H°rxn information provided to calculate (delta)H°f for HCl(g)
CH4(g) + 4Cl2(g) -> CCl4(g) + 4HCl(g)
(delta) H°rxn = -389 kJ
(delta) H°f of CH4(g) = -75 kJ/mol
(delta) H°f of CCl4(g) = -96 kJ/mol
-92 kJ/mol
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
-45.9 kJ
(T/F)
Heat capacity: The quantity of heat required to change a system’s temperature by 1°C
True
(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 Cs)
True
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)
28.4°C
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.
2.90 * 106 J/mol
Choose the reaction that illustrates (delta)H°f for Ca(NO3)2
A- Ca(s) + N2(g) + 3O2(g) -> Ca(NO3)2(s)
B- Ca+(aq) + NO3-(aq) -> Ca(NO3)2(s)
C-Ca+(aq) + NO3(aq) -> Ca(NO3)2(s)
D- Ca(s) + N2(g) + O2(g) -> Ca(NO3)2(s)
E- 2Ca(s) + 2N2(g) +3O2(g) -> Ca(NO3)2(s)
A
Identify a green-house gas
A- O3(g)
B- C2H4(g)
C- CO2(g)
D- H2O(g)
E- More than one correct answer is given
E
A, C, D are all correct
(T/F)
The temperature of pressure for the standard state for a liquid are 298 K and 1 atm
true
Give teh equation with the elements Na2SO4 in their standard state as the reactants and Na2SO4 as the product.
2Na(s) + 1/8S8(s, rhombic) +2O2(g) -> Na2SO4