CHEM 1100 STUDY GUIDE 2
How many liters of 0.200 M NaOH solution are required to completely react with 1.00 L of 0.100 M HCN solution to produce sodium cyanide and water?
0.50 L
A sample of gas at 30C changes volume from 20.0 mL to 25.0 mL. If the pressure remained constant, what is the final temperature of the gas?
106 degrees C
How many grams of solid magnesium chloride, MgCl2, are needed to make 250 mL of 0.50 M solution?
12 g
What is the temperature if 3.0 g of propane (C3H8) in a 400.0 mL container exerts a pressure of 5.5 atm?
121degreesC
Given the following thermochemical equation detailing the combustion of methane CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g) (delta)Hrxn = -802kJ/mol CH4 determine the amount of energy released when 25.0 g of methane undergoes combustion.
1250 kJ
A food sample was burned in a bomb calorimeter containing 524 mL water. How much thermal energy was produced when the temperature of the water and the calorimeter rose from 20.0(degrees)C to 25.0(degrees)C? The metal calorimeter had a heat capacity of 725 J/(degrees)C without the water. The specific heat capacity of water is 4.184 J/(g (degrees)C).
14.6 kJ
Before the development of reliable batteries, miners' lamps burned acetylene produced by the reaction of calcium carbide with water. A typical lamp used 0.75 L of acetylene per hour at 1.00 atm pressure and 20°C. How many grams of calcium carbide and how many grams of water had to be in the lamp for a 4-hour shift? CaC2(s) + H2O(l) --> C2H2(g) + CaO(s)
8.0 g CaC2 and 2.2 g H2O
Using the following data for water, determine the energy required to convert 2.00 moles of liquid water to steam (gas phase water) at its boiling point. Boiling point 373 K Melting point 273 K Enthalpy of vaporization 2,260 J/g Enthalpy of fusion 334 J/g Specific heat capacity (solid) 2.11 J/(g x K) Specific heat capacity (liquid) 4.18 J/(g x K) Specific heat capacity (gas) 2.08 J/(g x K)
81.4 kJ
In which one of the following compounds is the oxidation number of silicon not equal to +4?
Mg2Si
The density of a gaseous compound of nitrogen and oxygen is 4.11 g/L at STP. What is the most likely formula of this gas?
N2O4
In which one of the following compounds is the oxidation number of S equal to +4?
Na2SO3
In terms of the kinetic molecular theory, gases exert pressure due to ________
collisions of molecules with the walls of a container.
In which means that ________. going from the top to the bottom of the activity series below, the ease of oxidation of the metal ________,
decreases; magnesium can reduce zinc ions
What are the units of molar concentration, M ?
mol/L
A pot of water is heated with 10 J of energy at constant pressure. What is the enthalpy change ((delta)H) for this process?
+10 J
The oxidation number of carbon in carbon dioxide is ________
+4
What is the oxidation number of S in H2SO4?
+6
Tube worms that survive near geothermal vents of hydrogen sulfide rely on bacteria living inside them to obtain energy by the oxidation of H2S to SO42. What is the overall change in the oxidation number of sulfur for this reaction?
+8
Given the standard enthalpies of formation for the following substances, determine the reaction enthalpy for the following reaction. 2N2H4(g) + 2NO2(g) --> 3N2(g) + 4H2O(g) (Delta)Hrxn = ? kJ Substance N2H4(g), NO2(g), H2O(g) (Delta)H(degrees)f in kJ/mol +95.4 +33.1 -241.8
-1,220 kJ
Steam in a cylinder is compressed by a piston exerting a constant pressure of 5 atm. The volume of the cylinder decreases by 15 L and simultaneously the steam is cooled, losing 105 kJ of energy as heat. How much energy, total, was gained or lost by the steam in this process? (101.3 J = 1 L atm)
-113 kJ
How much work does a gas do when it expands against a constant pressure of 0.500 atm from a volume of 50.00 mL to a volume of 350.00 mL? (101.3 J 1 L atm)
-15.2 J
In a steam engine, steam in a cylinder expands against a piston, exerting 10 atm of external pressure. The volume of the cylinder increases by 10 L and simultaneously the steam cools, losing 3,000 kJ of energy to the surroundings. What is the change in energy of the steam? (101.3 J = 1 L atm)
-3,010 kJ
What is the change in internal energy (E) of a system when it loses 10 kJ of energy and 5,000 J of work is done on the system?
-5 kJ
When 2.50 g of sucrose (molar mass = 342.30 g/mol) reacts with excess oxygen in a constant volume calorimeter, the temperature of the calorimeter increases by 9.17(degrees)C. The heat capacity of the calorimeter is 4.90 kJ/(degrees)C. Determine the heat of combustion per mole of sucrose.
-6,150 kJ/mol
When 1.14 g of octane (molar mass = 114 g/mol) reacts with excess oxygen in a constant volume calorimeter, the temperature of the calorimeter increases by 10.0(degrees)C. The heat capacity of the calorimeter is 6.97 kJ/(degrees)C. Determine the energy flow, q (reaction).
-69.7 kJ
10.0 g of ammonium nitrate ((delta)Hsoln = 25.7 kJ/mol, molar mass = 80.0 g/mol) dissolves in 100.0 g of water. What is the change in temperature of the solution? Assume the specific heat capacity of the solution is 4.2 J g^-1 oC^-1.
-7.0(degrees)C
A 125 mL sample of orange juice was titrated using a redox reaction to the equivalence point with the addition of 7.6 mL of a 0.0025M iodine (I2) solution. What is the concentration of vitamin C (C6H8O6) in this sample? C6H8O6(aq) + I2(aq) --> C6H6O6(aq)+ 2I-(aq) + 2H+(aq)
.15mM
Dr. Dave's supercharged GTI has a 4-cylinder engine. Each cylinder has a volume of 500 mL. Air (20% O2, 80% N2) is fed into the cylinders at a pressure of 2 atm and a temperature of 80C. How many moles of oxygen are there in each cylinder?
0.0069 mol
In an experiment, 30.0 g of metal was heated to 98.0(degrees)C and then quickly transferred to 50.0 g of water in a calorimeter. The heat capacity of the calorimeter with the water was 211 J/(degrees)C. The initial temperature of the calorimeter was 27.0(degrees)C, and the final temperature after addition of the metal was 32.5(degrees)C. What is the value of the specific heat capacity of the metal?
0.591 J/(g (degrees)C)
What mass of potassium iodide (molar mass = 166.0 g/mol) is needed to produce 325.0 mL of a solution that has a concentration of 0.0150 M ?
0.809 g
Which one of these samples contains the smallest number of particles (atoms or molecules)? Explain your logic. 1.0 L of H2 at STP (0degreesC and 1 atm) 1.0 L of N2 at STP 1.0 L of H2 at 20degreesC and 760 torr 1.0 L of N2 at 0degreesC and 800 torr 1.0 L of He at STP
1.0 L of H2 at 20C and 760 torr. All the samples at STP contain the same number of particles. The one with the higher temperature and lower pressure will contain the smaller number of the two remaining. At the higher temperature fewer molecules are needed to produce the pressure because their average velocity is higher. The sample at 800 torr has more molecules, which is why the pressure is higher.
How many moles of ammonium hydroxide are present in 100 mL of a 0.17 M solution?
1.7 x10^2 moles
If one regular antacid tablet contains 500 mg of solid CaCO3 (100 g/mol), how many mL of 1.0 M stomach acid (HCl) could it neutralize?
10 mL
The cooling system in an automobile holds 10.0 L of ethylene glycol antifreeze. How much energy is absorbed when the temperature of the ethylene glycol goes from 20(degrees)C to 100(degrees)C? The density and specific heat capacity of ethylene glycol are 1.11 g/mL and 2.42 J/(g (degrees) C), respectively.
2,150 kJ
Sodium fluoride (NaF) is added to drinking water in some municipalities to protect teeth against cavities. The idea is to convert hydroxyapatite, Ca10(PO4)6(OH)2, into more stable fluorapatite, Ca10(PO4)6F2. The molar mass of hydroxyapatite is 502 g/mol. What is the molarity of a 10.0 mg/L sodium fluoride solution?
2.38x10^4 M
A medical saline solution is prepared by mixing 55 mg of morphine (C17H19NO3) with water to make 75.0 mL of solution. What is the millimolar concentration of this solution?
2.57mM
What is the heat capacity (Cp) of a 7.5 g piece of tin if its temperature changes by 12.3(degrees)C when it is supplied with 20 J from a Bunsen burner?
25.77 J/(mol (degrees) C)
What will be the final temperature of a 10.0 g piece of iron (CP = 25.09 J/(mol · (degrees)C)) initially at 25(degrees)C, if it is supplied with 9.5 J from a stove?
27(degrees)C
Predict the temperature change produced by burning 3.55 g benzoic acid in a bomb calorimeter that has a heat capacity of 20.12 kJ/(degrees)C. The enthalpy of combustion of benzoic acid is -26.43 kJ/g.
4.66(degrees)C
What is the concentration, in g/L, of a 0.100 M sodium chloride solution?
5.84 g/L
If 1.0 L of 1.0 M HCl spilled and needed to be neutralized, how many grams of the solid sodium carbonate (Na2CO3, 106 g/mol) would be required?
53 g
Oxygen for astronauts in space can be produced chemically using a solid fuel oxygen generator. The reaction takes place at 600 degrees C and is shown below. NaClO3(s) + Fe(s) --> 3O2(g) + NaCl(s) + FeO(s) What volume of O2 gas will be produced when 855 g of NaClO3 reacts with excess iron at a pressure of 3 atm?
575 L
Using the following data for water, determine the energy required to melt 1.00 mole of ice (solid water) at its melting point. Boiling point 373 K Melting point 273 K Enthalpy of vaporization 2,260 J/g Enthalpy of fusion 334 J/g Specific heat capacity (solid) 2.11 J/(g K) Specific heat capacity (liquid) 4.18 J/(g K) Specific heat capacity (gas) 2.08 J/(g K)
6.02 kJ
What mass of lead(II) chloride is produced when 200.0 mL of a 0.250 M solution of sodium chloride is mixed with 200.0 mL of a 0.250 M solution of lead(II) nitrate.
6.95 g
What volume of 0.25 M hydrochloric acid (HCl) solution contains 0.15 mol HCl?
600mL
Commercial hydrochloric acid is 12.1 M. What volume of commercial HCl solution should be used to prepare 250.0 mL of 3.00 M HCl?
62mL
Which one of the following statements regarding a strong acid is not correct?
Acids are only strong at a high concentration.
Which of the following compounds are soluble in water? PbCO3 , Fe2S3 , AgNO3, NH4OH
AgNO3, and NH4OH
Which one of the following statements is not correct?
An oxidizing agent is a substance that is oxidized in a chemical reaction
Which of the following ionic compounds is insoluble in water?
BaSO4
In the following reaction, which element or ion is reduced? Cl2(g) + NaBr(aq)-->NaCl(aq) + Br2(g)
Cl2
In the following reaction, which element is oxidized? Cu + FeSO4 --> Fe + CuSO4
Cu
The following graph shows the gas speed distributions for four different gases, all at the same temperature. Select the curve that represents the heaviest gas and explain your rationale for the choice.
Curve A represents the heaviest gas. The heaviest gas at a constant temperature will have the lowest overall root-mean-square speed, which corresponds to Curve A.
Which arrow in the following diagrams represents an exothermic phase transition?
Gas | | v Liquid Solid
Identify the oxidizing agent in the following reaction. 2Hg2^2+(aq) + Sn^2+(aq) --> 2Hg(l ) + Sn^4+(aq)
Hg2^2+(aq)
Write the net ionic equation for the reaction that takes place between a solution of potassium chloride and a solution of lead nitrate.
Pb2^2+(aq) + 2Cl^-(aq) --> PbCl2(s)
Write the complete ionic equation for the reaction that takes place between a solution of lead(II) nitrate and sodium sulfate.
Pb^2+(aq) + 2NO3^-(aq) + 2Na^+(aq) + SO4^2-(aq) --> PbSO4(s)+ 2Na^+(aq) + 2NO3^-(aq)
Which one of the following statements regarding a weak base is not correct?
Sodium hydroxide is an example of a weak base.
Explain why the constants a and b in the van der Waals equation for the noble gas elements increase with increasing atomic number.
The atoms become larger and more polarizable, so the strength of the interactions between atoms increases. The van der Waals constants account for the increasing size and interactions.
Which molecules in air have the highest average speeds, oxygen or nitrogen? Explain.
The kinetic energies depend only on the temperature and therefore are the same. Given that oxygen is heavier than nitrogen, nitrogen molecules must have the higher average speeds because KE 1/2 mu2.
Which contains more solute particles: a 0.10 M aqueous solution of methanol (CH3OH) or a 0.10 M aqueous solution of salt (NaCl)?
The salt solution contains twice as many particles as the methanol solution.
The thermite reaction is used in welding applications and chemistry demonstrations because it releases a tremendous amount of energy. Which of the following statements is not correct regarding this reaction? 8Al + 3Fe3O4 --> 9Fe + 4Al2O3
Three electrons are transferred from each aluminum atom to each iron atom.
A chemistry student attempted to make a 0.2000 M solution of NaCl using a 100.0 mL volumetric flask. She added exactly 100.0 mL of water to the flask, then added 0.02000 mol of NaCl, and found that the total volume in the flask was above the 100.0 mL mark. What was the concentration of the solution?
a bit less than 0.2000 M
A homogeneous mixture of two or more substances is called ________
a solution
Write the equation that corresponds to the standard enthalpy of formation for each of the following compounds: a) NaI(s), b) HClO4(g), and c) CH3OCH3(g)
a) Na(s) + 1/2 I2(s) --> NaI(s) b) 1/2 H2(g)+ 12Cl2(g)+2O2(g)--> HClO4(g) c) 2C(s, graphite) + 3H2(g) + 1/2 O2(g) --> CH3OCH3(g)
Which one of the following is not a polyprotic acid?
acetic acid, CH3COOH
During a(n) ________ process, energy is transferred to the system from the surroundings.
endothermic
During a(n) ________ process, energy is transferred from the system to the surroundings.
exothermic
Which of the following depicts a solution
o.o.o.o.o.o.o.o
Concentrated sulfuric acid contains 4 g of water for every 100 g of solution. The solvent is ________
sulfuric acid
In the dilution of 10.0 mL of a 0.10 M solution of HCl to a volume of 20.0 mL, what remains unchanged?
the moles of HCl in the solution