Chem 201 test 4 (quiz/hw answers)
For data using a bomb calorimeter (constant volume calorimetry), which of the following for a reaction Hint: a bomb calorimeter is the laboratory equipment used to measure energy exchanges at constant volume between the system and the surroundings via temperature changes of the surroundings. A) (Delta)Erxn= -P(delta)V B) (Delta)Erxn= qv-P(delta)V C) (Delta)Erxn= qv D) (Delta)Erxn= qv + w
(Delta)Erxn= qv
which statement is false? A) Enthalpy is the sum of a systems internal energy and the product of pressure and volume. B) (delta symbol)Erxn is the measure of heat. C)An exothermic reaction gives off heat to the surroundings. D)Endothermic has positive (delta symbol)H. E) (delta symbol)Hrxn is the heat reaction.
(delta symbol)Erxn is the measure of heat.
The combustion of titanium with oxygen produced titanium dioxide. Ti(s) + O2(g) --> TiO2(s) When 2.060g of titanium is combusted in a bomb calorimeter, the temperature of the calorimeter increases from 25.00°C to 91.60°C. In a separate experiment the heat compacity of the calorimeter is measured to be 9.84 kJ/K. The heat of reaction for combustion of a mole of Ti in this calorimeter is _______ kJ/mol A) 19.6 B) -0.154 C) -1.52 x 10^4 D) -311 E) 14.3
-1.52 x 10^4
Use the standard reaction enthalpies given below to determine (delta)H°rxn for the following reaction: 2NO(g) + O2 --> 2NO2 (Delta)H°rxn = ?? Given N2(g) + O2(g) --> 2NO(g) (delta)H°rxn = - 182kJ 1/2N2(g) + O2(g) --> NO2(g) (Delta)H°rxn = 33kJ A) -150kJ B) -117kJ C) -333kJ D) 238kJ E) 115kJ
-117kJ
The volume of 350. mL of gas at 25°C is decreased to 135 mL at constant pressure. What is the final temperature of the gas? A) 65°C B) -158°C C) 9.6°C D) 500°C
-158°C
The enthalpy for the formation of 1 mole of NH3(ag) is -80.29 kJ/mol. What is the enthalpy for the formation of 3 mole of NH3(ag) Hint: Does the enthalpy of a reaction change with a different amount of product formed? Enthalpy is an extensive property and enthalpy for this reaction will be 3 times the enthalpy of formation for 1 mole of NH3(ag) A) -240.87kJ B) -83.29kJ C) -26.76kJ D) -518 x 10^3kJ
-240.87kJ
Two solutions, initially at 24.60C, are mixed in a coffee cup calorimeter (Ccal = 15.5 J/°C). When a 100 mL volume of .100 M AgNO3 is mixed with a 100 mL sample of .200 M NaCl solution, the temperature in the calorimeter rises to 25.30°C. Determine the (delta)H°rxn for the reaction as written below. Assume that the density and heat capacity of the solutions is the same as that of water. NaCl(ag) + AgNO3(ag) --> AgCl(s) + NaNO3(ag) (delta)H°rxn = ? A) -59kJ B) -259kJ C) -16kJ D) -140kJ E) -35kJ
-59kJ
Calculate the enthalpy change for the following reaction: N2H4(g) + O2(g) --> N2(g) + 2H2O(l) (delta)H°rxn = ? Given N2(g) + O2(g) --> N2(g) + 2H2O (delta)H°1 = 95.4 kJ H2(g) + 1/2O2(g) --> H2O(l) (delta)H°2 = -285.8 kJ A) -190.4 kJ B) -476.2 kJ C) -667.0 kJ D) -381.2 kJ
-667.0 kJ
Consider the following reaction: 2A + 3B --> D (delta)H°rxn = 45.7kJ. What is (delta)Hrxn for the following reaction: 2D --> 4A + 6B... Hint: Review the 3 quantitative relationships between a chemical equation and (delta)Hrxn. A) -23.8kJ B) -91.4kJ C) 91.4kJ D) -45.7kJ
-91.4kJ
How many grams of KCl(s) are produced from the thermal decomposition of KClO3(s) which produces 50.0 mL of O2(g) at 25°C and 1.00 atm pressure according to the chemical equation shown below?2 KClO3(s) → 2 KCl(s) + 3 O2(g)? A) 0.102 g B) 0.167 g C) 0.304 g D) 0.152 g
0.102 g
Zinc reacts with aqueous sulfuric acid to form hydrogen gas: Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) In an experiment, 225 mL of wet H2 is collected over water at 27°C and a barometric pressure of 748 torr. How many grams of Zn have been consumed? The vapor pressure of water at 27°C is 26.74 torr. A) 431 B) 0.567 C) 567 D) 4.79 × 10^6 E) 4.31 × 10^5
0.567
A mixture of 0.220 moles CO, 0.350 moles H2 and 0.640 moles He has a total pressure of 2.95 atm. What is the pressure of H2? A) 0.969 atm B) 0.853 atm C) 0.649 atm D)1.17 atm E) 1.03 atm
0.853 atm
Which one of these will diffuse the fastest at 25°C? A) 1.0 M H B) 2.0 M N C) 2.0 M O D)2.0 M Ar E) 0.5 M Ne
1.0 M H
Using the following thermochemical equation, determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6) 2C6H6(l) + 15O2(g) --> 12CO2(g) + 6H2O(g) (delta)H°rxn = -6278kg A) 4.34 x 10^4 kJ/kg CO2 B) 2.30 x 10^4 kJ/kg CO2 C) 8.40 x 10^5 kJ/kg CO2 D) 1.19 x 10^4 kJ/kg CO2 E) 1.43 x 10^5 kJ/kg CO2
1.19 x 10^4 kJ/kg CO2
A basketball is inflated to a pressure of 1.90 atm in a 24.0°C garage. What is the pressure of the basketball outside where the temperature is -1.00°C? A) 1.74 atm B) 2.00 atm C) 1.80 atm D) 2.08 atm
1.74 atm
Which gas sample has the greatest volume at STP? A) 10.0 g Cl2 B) 10.0 g O2 C) 10.0 g F2 D) None of the above (They all have the same volume.)
10.0 g O2
Which of the following substances (with specific heat capacity provided) would show the greatest temperature change upon absorbing 100.0 J of heat? A) 10.0 grams of ethanol, C ethanol = 2.42 J/g°C B) 10.0 grams of Pb, C Pb = 0.128 J/g°C C) 10.0 grams of Fe, C Fe = 0.449 J/g°C D) 10.0 grams of H2O, C H2O = 4.18J/g°C E) 10.0 grams of Ag, C Ag = 0.435J/g°C
10.0 grams of Pb, C Pb = 0.128 J/g°C
Calculate the amount of heat (in kJ) required to raise the temperature of a 79.0g sample of ethanol from 298K to 351K The specific heat compacity of ethanol is 2.42J/g°C. A) 57kJ B) 12.9kJ C) 73.6kJ D) 10.1kJ E) 28.4kJ
10.1kJ
Using the following equation for the combustion of octane, calculate the amount of moles of oxygen that reacts with 100.0g of octane. The molar mass of octane is 114.33 g/mol. The molar mass of carbon dioxide is 44.0095g/mol. 2C8H18 + 25 O2 --> 16CO2 + 18H2O (delta)H°rxn = -11018kJ A) 6.997 Moles B) 14.00 Moles C) 18.18 Moles D) 8.000 Moles E) 10.93 Moles
10.93 Moles
How many grams of XeF6 are required to react with 0.579 L of hydrogen gas at 6.46 atm and 45°C in the reaction shown below?XeF6(s) + 3 H2(g) → Xe(g) + 6 HF(g) A) 9.58 g B) 35.2 g C) 11.7 g D)106 g
11.7 g
Use the standard reaction enthalpies given below to determine (delta)H°rxn for the following reaction: 4SO3(g) --> 4S(s) + 6O2 (delta)H°rxn = ?? Given SO2(g) --> S(s) + O2(g) (delta)H°rxn = 269.8kJ 2SO2(g) + O2(g) --> 2SO3(g) (delta)H°rxn = -197.8kJ A) -494.6kJ B) 1583kJ C) -791.4kJ D) -692.4kJ E) -293.0kJ
1583kJ
The mole fraction of argon in dry air near sea level is 1.818 × 10-5 where the molar mass of argon is 39.948. The concentration of argon in the atmosphere is ________ ppm. A) 9.34 × 10^6 B) 18.18 C) 9.34 × 10^9 D) 0.934 E) 1.07 × 10^8
18.18
According to the following reaction, how much energy is required to decompose 59.0kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g/mol. Fe3O4(s) --> 3Fe(s) + 2O2(g) (delta)H°rxn = 1,118kJ A) 8.55 x 10^5kJ B) 2.85 x 10^5kJ C) 1.42 x 10^5kJ D) 5.70 x 10^5kJ E) 1.13 x 10^5kJ
2.85 x 10^5kJ
What is the total volume of the mixture of hydrogen gas and oxygen gas can be obtained from the electrolysis of 110.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below?2 H2O(l) → 2 H2(g) + O2(g) A) 447 L B) 224 L C) 74.7 L D) 149 L
224 L
The enthalpy change for the formation of 1 mole of Ch4 from its elements in their standard states is -74.6kJ/mol. C(s, graphite) + 2H2(g) --> CH4(g) DeltaH°f = -74.6 kJ. What is the enthalpy change associated with the decomposition of 3 moles of methane? A) 74.6 kJ B) -224 kJ C) 24.9 kJ D) 244 kJ
244 kJ
The atmospheric pressure is 700 mm Hg. What is the pressure in inches of Hg? A) 0.921 in Hg' B) 32.5 in Hg C) 16.0 in Hg D) 27.6 in Hg E) 13.5 in Hg
27.6 in Hg
The density of krypton gas at 1.21 atm and 50.0°C is ________ g/L. A) 0.0456 B) 0.295 C) 0.262 D) 7.65 E) 3.82
3.82
How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0°C and 0.975 atm pressure according to the chemical equation shown below? CaH2(s) + 2 H2O(l) → Ca(OH)2(aq) + 2 H2(g) A) 3.82 g B) 7.64 g C) 45.6 g D) 15.3 g
3.82 g
Determine the specific heat capacity of an alloy that requires 59.3 kJ to raise the temperature of 150.0 g alloy from 298 K to 398 K. A) 2.29 J/g°C B) 2.53J/g°C C) 1.87J/g°C D)3.95J/g°C E)4.38J/g°C
3.95J/g°C
What volume will a balloon occupy at 1.0 atm, if the balloon has a volume of 8.8 L at 4.4 atm? A) 2.0 L B) 39 L C) 13 L D) 0.50 L E) 4.4 L
39 L
The concentration of ozone in a sample of air that has a partial pressure of O3 of 0.33 torr and a total pressure of air of 735 torr is ________ ppm. A) 2.20 B) .45 C)4.5 × 10^2 D) 0.045 E)2.2 × 10^-3
4.5x10^2
When 14.0 g of zinc metal reacts with excess HCl, how many liters of H2 gas are produced at STP? A)4.80 L B)0.208 L C)9.60 L D) 0.416 L
4.80 L
A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mm Hg. What volume of gas will the balloon contain at 1.35 atm and 253 K? A) 58.6 L B) 22.2 L C)11.4 L D)87.5 L E)45.0 L
45.0 L
What volume (in mL) will a sample of F2 gas occupy in a syringe at 5.5 atm, if the F2 has a volume of 25.0 mL at 1.2 atm? A) 7.6 mL B) 11 mL C) 5.5 mL D) 17 mL E) 3.8 mL
5.5 mL
To what volume will a sample of gas expand if it is heated from 50.0°C and 2.33 L to 500.0°C? A) 5.58 L B) 23.3 L C) 0.97 L D) 0.233 L E) 0.184 L
5.58 L
How many liters of oxygen are needed to exactly react with 19.8 g of methane at STP? CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) A) 13.9 L B) 60.5 L C) 27.8 L D) 55.5 L
55.5 L
According to the following reaction, how much energy is evolved during the reaction of 0.111 mol B2H6 and 0.252 mole Cl2 (both gases are initially at STP)? Molar mass of B2H6 is 27.67 g/mol. B2H6(g) + 6Cl2(g) --> 2BCl2(g) + 6HCL(g) (delta)H°rxn = -1396kJ A) 352 kJ B) 508 kJ C) 215 kJ D) 156 kJ E) 58.7 kJ
58.7 kJ
A 6.55g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a coffee-cup (Bomb) calorimeter. If the temperature rose by 32.9°C, use the information below to determine the heat compacity of the calorimeter. 4C6H5NH2(l) + 35O2(g) --> 24CO2(g) + 14H20(g) + NO2(g) (Delta symbol)H°rxn= -1.28x10^4kJ A)97.3kJ/°C B)38.9kJ/°C C)5.94kJ/°C D)12.8kJ/°C E)6.84kJ/°C
6.84kJ/°C
Consider this combination reaction: 2MG(s) + O2(g) --> 2MgO(s) (Delta)H = -1204kJ What is the enthalpy for the decomposition of 1 mole of MgO(s) into Mg(s) and O2(g) Hint: How is the decomposition reaction related to the combination reaction? The decomposition reaction is the reverse reaction of this combination reaction, Notice that the question is asking for the enthalpy of 1 mole of MgO; the combination reaction given forming 2 moles of MgO. A) -602 kJ/mol B) 1204 kJ/mol C) 602 kJ/mol D) -1204 kJ/mol
602 kJ/mol
What is the pressure in a gas container that is connected to an open-end U-tube manometer if the pressure of the atmosphere is 742 torr and the level of mercury in the arm connected to the container is 8.60 cm higher than the level of mercury open to the atmosphere? A) 828 mm Hg B) 656 mm Hg C) 751 mm Hg D) 733 mm Hg
656 mm Hg
If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy under the same conditions? A)5.0 L B)17 L C)15 L D)8.6 L E)12 L
8.6 L
A 12.8g sample of ethanol (C2H5OH) is burned in a coffee-cup calorimeter with a heat capacity of 5.65kJ/°C. using the information below, determine the final temperature of the calorimeter if the initial temperature is 25.0°C. The molar mass of ethanal is 46.07 g/mol. C2H5OH(l) + 3O2 --> 2CO2(g) + 3H2O(G) (Delta symbol)H°rxn = -1,235kJ A) 28.1°C B) 74.2°C C) 85.7°C D) 53.4°C E) 111°C
85.7°C
Convert 1.25 atm to torr. A)950 torr B)1530 torr C)1000 torr D)875 torr E)760 torr
950 torr
Look at answer key for quiz 7 there are some diagrams that I can put on here.
:)
There are 2 tables in assignment 7 that I could not put in here would recommend looking over that.
:)
The standard heat of formation of AgCl(s) is -127.0 Kj/mol. which of the following equation is associated with this heat of formation value. Hint: definition of standard heat of formation of a compound is the change in enthalpy when 1 mole of a compound forms from its constituent element in their standard states. A) AgCl(s) --> Ag(s) + 1/2Cl2(g) B) Ag(s) + 1/2Cl2(g)--> AgCl(s) C) Ag(s) + Cl2(g)--> AgCl(s) D) 2Ag(s) + Cl2(g)--> 2AgCl(s)
Ag(s) + 1/2Cl2(g)--> AgCl(s)
Which of the following statements is TRUE? A) Particles of different masses have the same average speed at a given temperature. B) For a given gas, the lower the temperature, the faster it will effuse C) The larger a molecule, the faster it will effuse. D) At very high pressures, a gas will occupy a larger volume than predicted by the ideal gas law. E) None of the above statements are true.
At very high pressures, a gas will occupy a larger volume than predicted by the ideal gas law.
Which of the following equations describes the formation of a compound from its elements in their standard state? Hint: Recall that an elements standard state is its most stable at standard conditions (298K, 1atm) A) 2NH3(g) --> N2(g) + 3H2(g) B) C(s, Graphite) + O2(g) --> CO2(g) C) N20(g) + 4H2(g) --> 2NH3(g) + H2O(l) D) 2CH4(g) + 4O2 --> 2CO2(g) $H2O(l)
C(s, Graphite) + O2(g) --> CO2(g)
Rank the gases Kr, N2, CH4, and C3H8 in order of increasing density at STP. A) CH4 < C3H8 < N2 < Kr B) CH4 < N2 < C3H8 < Kr C) CH4 < N2 < Kr < C3H8 D) Kr < C3H8 < N2 < CH4
CH4 < N2 < C3H8 < Kr
The density of a gas is 3.16 g/L at STP. What is the gas? A) Kr B) Br2 C) Cl2 D) Ar E) H2
Cl2
Choose the reaction that illustrates (delta)H°f for CsHCO3 A) Cs^+(ag) + HCO3^-1(ag) --> CsHCO3(s) B) Cs(ag) + 1/2H2(g) + C(s) + 3/2O2(g) --> CsHCO3(s) C) Cs(ag) + H2(g) + C(s) + O2(g) --> CsHCO3(s) D) Cs^+(ag) + H2O(l) + CO2(g) --> CsHCO3(s) E) Cs(ag) 2H(g) + C(s) + 3O(g) --> CsHCO3(s)
Cs(ag) + 1/2H2(g) + C(s) + 3/2O2(g) --> CsHCO3(s)
For a particular process that is carried out at a constant pressure q = 145 kJ and w = 35 kJ Therefore, A) DeltaE = 145kJ and DeltaH = 180kJ B) DeltaE = 110kJ and DeltaH = 145kJ C) DeltaE = 180kJ and DeltaH = 145kJ D) DeltaE = 145kJ and DeltaH = 110kJ
DeltaE = 110kJ and DeltaH = 145kJ
What are the basic postulates of kinetic molecular theory? Check all that apply. A) The size of a particle is considerable. B) The collision of one particle with another (or with the walls) is completely elastic. C) The collision of one particle with another (or with the walls) is completely nonelastic. D) The average kinetic energy of a particle is inversely proportional to the temperature in kelvins. E) The size of a particle is negligibly small. F) The average kinetic energy of a particle is proportional to the temperature in kelvins.
E) The size of a particle is negligibly small. B) The collision of one particle with another (or with the walls) is completely elastic. F) The average kinetic energy of a particle is proportional to the temperature in kelvins.
Define Kinetic Energy. A) Energy associated with the force of an object B) Energy associated with the temperature of an object C) Energy associated with the gravity of an object D) Energy associated with the motion of an object E) Energy associated with the position or composition of an object
Energy associated with the motion of an object
Define thermal energy. A) Energy associated with the position or composition of an object B) Energy associated with the gravity of an object C) Energy associated with the temperature of an object D) Energy associated with the motion of an object E) Energy associated with the force of an object
Energy associated with the temperature of an object
Identify the gas particle that travels the slowest. A) CO B) N2 C) H2 D) Ne E) F2
F2
Identify an element that is not in its standard state. A) H2 (g) B) H(g) C) Ca(s) D) Xe(g)
H(g)
If the enthalpy change of a reaction in a flask is (delta)H = 67kJ, what can be said about the reaction? Hint: when (delta)H is positive the reaction is endothermic A) Heat is transferred from the surroundings to the reaction flask B) Heat us transferred from the reaction flask to surroundings C) The flask feels warm D) 67kJ of heat is released by the reaction
Heat is transferred from the surroundings to the reaction flask.
Give the units of heat capacity. A) Jmole/°C B) Mole/°C C) J/°C D) g/°C E) J/°C
J/°C
Which of the following statements about energy is false? A) Energy is the capacity to do work B) Systems tend to change in order to lower their potential energy C) Kinetic energy is the energy associated with its position or composition D) Energy can be converted from one type to another
Kinetic energy is the energy associated with its position or composition
Which of the following gases has the lowest average speed at 25°C? A) Kr B) CH3NH2 C) SO2 D) C3H8
Kr
Using the graph below, determine the gas that has the highest density at STP. (Could not insert graph) A) Line A B) Line B C) Line C D) Line D E)All of the gases have the same density at STP.
Line D
An instrument used to measure the pressure of a gas in a laboratory is called a A) sphygmomanometer barometer B) spectrometer C) Spectrophotometer D) Manometer
Manometer
Which of the following compounds would have the largest lattice energy? Hint: Factor that determining lattice energy: The lattice energy depend on both charges of the ion and ionic radius. A) NaBr B) CaO C) MgO D) NaCl
MgO
The rate of effusion of oxygen to an unknown gas is 0.935. What is the other gas? A) N2 B) F2 C) Ne D) Ar
N2
Place the following gases in order of increasing density at STP. F2, NH3, N2O4, Ar A) Ar < N2O4 < F2 < NH3 B) N2O4 < Ar < F2 < NH3 C) F2 < Ar < N2O4 < NH3 D) NH3 < F2 < Ar < N2O4 E) Ar < F2 < NH3 < N2O4
NH3 < F2 < Ar < N2O4
A gas mixture contains an equal number of moles of He and Ne. The total pressure of the mixture is 8.0 atm. What are the partial pressures of He and Ne? A) PHe=5.0atm;PNe=3.0atm B) PHe=3.0atm;PNe=5.0atm C) PHe=4.0atm;PNe=4.0atm
PHe=4.0atm;PNe=4.0atm Because the number of moles of each gas is equal, the mole fraction of each gas is 0.50 and the partial pressure of each gas is 0.50×Ptot
Which of the following processes is endothermic? A) Rusting Iron B) Mixing water and acid C) Photosynthesis D) The electron affinity of a fluorine atom E) None of these are endothermic
Photosynthesis
Define heat capacity. A) The he quantity of heat required to lower the temperature of 1 mole of a substance by 1°C B) The quantity of heat required to change a system's temperature by 1°C C) The quantity of heat required to lower the temperature of 1 liter of a substance by 1°C D) The quantity of heat required to lower the temperature of 1 gram of a substance by 1°C E) The quantity of heat required to raise the temperature of 1 gram of by 1°F
The quantity of heat required to change a system's temperature by 1°C.
When HCl(aq) and NaOH(aq) are mixed in a beaker, the beaker feels warm to the touch. What is known about the enthalpy of this reaction? Hint: How does heat transfer relate to enthalpy? Endothermic reactions absorb heat from surroundings and exothermic reactions give of heat to surroundings. A) (Delta)H is positive B) Heat is absorbed from the surroundings C) The reaction is endothermic D) The reaction is exothermic
The reaction is exothermic.
All of the following statements concerning real gases are correct except A) nonideal gas behavior is described by the Van der Waals Equation. B) the pressure of a real gas at low temperatures is lower than for ideal gases. C) molecules of real gases are attracted to each other. D) the pressure of a real gas is due to collisions with the container. E) molecules of real gases occupy no volume.
molecules of real gases occupy no volume.
Define hypoxia. A) increased oxygen concentration in body tissues B) oxygen starvation C) increased nitrogen concentration in body tissues and fluids D) nitrogen starvation
oxygen starvation
Which of the following signs on q and w represent a system that is doing work on the surrounding, as well as gaining heat from the surroundings A) q=+, w=+ B) q=-, w=+ C) q=-, w=- D) q=+, w=- E) None of these represent the system referenced above
q=+, w=-
