| Assessment Questions: 40 results |
Solutions : FreezePtDepression (20 Variations)
It takes 6.86 kg of ethylene glycol (antifreeze) to decrease the freezing point of 6.50 kg of water to -25.0oF (-31.7oC). How much sodium chloride (NaCl) would it take to decrease the freezing point of 6.50 kg of water to -25.0oF? (Assuming all the salt will dissolve in that amount of water.)
Solutions / Solvents
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Solutions : GeneralSolutions (10 Variations)
You have 500.0mL of 0.100M aqueous MgBr2. Which of the following statements are true?
Solutions / Solvents
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Solutions : SolnPrepProcedure (10 Variations)
You want to prepare 250mL of a 0.0150M solution of KCl. Which of the following procedures would give you the best results?
Solutions / Solvents
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Solutions : SolutionNanoPics (4 Variations)
The drawings below represent flasks of aqueous solutions. Each pink dot represents a dissolved solute particle.
Which of the following solutions is most concentrated?
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500 mL
Solution A
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500 mL
Solution B
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500 mL
Solution C
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250 mL
Solution D
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250 mL
Solution E
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250 mL
Solution F
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Solutions / Solvents
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Thermochemistry : SystemSurrExoEndo (4 Variations)
Sulfuric acid is added to water in a beaker and the resulting solution is much warmer than either the water or acid was initially.
Identify the following items as being part of the system or the surroundings, and indicate whether the process is exothermic or endothermic.
Calorimetry / Thermochemistry
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Thermochemistry : BondEnergies (10 Variations)
Use  to determine which of the following requires the most energy.
Calorimetry / Thermochemistry
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Thermochemistry : FlaskTemp (6 Variations)
If 200. J of thermal energy was added to both flasks, which of the following would happen?
Calorimetry / Thermochemistry
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Thermochemistry : GeneralEnergy (10 Variations)
Which of the following statements about energy is NOT true?
Calorimetry / Thermochemistry
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Thermochemistry : ThermalEnergy (2 Variations)
The sketch below shows two identical flasks with different volumes of water at the same temperature. Which of the following is true?
Calorimetry / Thermochemistry
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Thermochemistry : HeatTransfers (10 Variations)
A red-hot piece of lead is dropped into water. Which of the following statements are true? (Assume that there are no energy transfers between anything except the lead and the water.)
Calorimetry / Thermochemistry
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Solutions : IonConcentration (4 Variations)
Which of the following solutions has the greatest concentration of Na+ ions?
Solutions / Solvents |
Chemometrics
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Solutions : MassSoluteInSoln (10 Variations)
What is the mass of the solute in 500mL of 0.341M ammonium chloride?
Solutions / Solvents |
Chemometrics
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Solutions : RelativeConc (4 Variations)
What are the relative concentrations of the ions in 0.10 M aqueous sulfuric acid?
Solutions / Solvents |
Stoichiometry
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Solutions : ReverseOsmosis (20 Variations)
You are given a water sample that contains ammonium chloride (NH4Cl). You determine the concentration of the salt to be 0.500 M and decide to purify the water using reverse osmosis. What is the minimum pressure that must be applied at 30.0oC to force the water through the membrane?
Solutions / Solvents |
Transport Properties
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Solutions : SolnConcAfterMixing (4 Variations)
10 mL of 0.1 M BaCl2(aq) is mixed with 10 mL of 0.1 M AgNO3(aq). What are the concentrations of the ions in the final mixture?
Solutions / Solvents |
Chemometrics
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Solutions : SolnPrepByDilution (10 Variations)
For the analysis of trace metals it is necessary to prepare solutions of very low concentrations from a stock solution of higher concentration using a micropipet and a volumetric flask. What volume of a 0.0010 M solution of Zn(NO3)2 (aq) would be required to prepare a 5.0 nM solution of Zn2+ in a 250mL flask?
Solutions / Solvents |
Chemometrics
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Solutions : SolnPrepByMass (4 Variations)
You are required to prepare 5 L of a solution containing 1.000 x 10-3 mol/L of Cu2+(aq). Which of the following procedures would produce an appropriate solution?
Solutions / Solvents |
Chemometrics
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Thermochemistry : BombCalorimeter (4 Variations)
Stearic acid (CH3(CH2)16CO2H) is a fatty acid, the part of fat that stores most of the energy. 1.00 g of stearic acid was burned in a bomb calorimeter. The bomb had a heat capacity of 652 J/oC and a 500. g water reservoir. If the temperature rose from 25.0 to 39.3 oC, how much heat was released when the stearic acid was burned?
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : CalcHStateChange (4 Variations)
Calculate the enthalpy change when 100. g of ice at 0.0 oC is heated to liquid water at 50.0oC. (The heat of fusion for water is 333 J/g.)
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : CoffeeCupCalorimeter (2 Variations)
A block of copper is heated to {x} °C and then is dropped into a coffee cup calorimeter containing {y} g of water at 25.0 °C. The final temperature of the system is 45.1 °C. What is the mass of the copper block to the nearest gram? (Assume all heat is transferred to the water). Write your answer in the box, and do NOT include units.
Specific heat capacity of copper = 0.383 J/(g*°C)
Specific heat capacity of water = 4.18 J/(g*°C)
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : FuelAmpWattHeat (4 Variations)
Gasoline has an enthalpy of combustion of approximately 24000 kJ/gallon. When gasoline burns in an automobile engine, approximately 30% of the energy released is used to produce mechanical work. The remainder is lost as heat transfer to the engine's cooling system and eventually the atmosphere. As a start on estimating how much heat transfer is required, calculate what mass of water could be heated from 25 to 100oC by the combustion of 1.0 gallon of gasoline in an automobile.
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : HeatCapacityGraph (6 Variations)
Consider the graph above. Which of these substances has the highest specific heat capacity?
Calorimetry / Thermochemistry |
Heat Capacity
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Thermochemistry : HeatCapacityLiq (4 Variations)
100 g of water (c=4.184 J/g.oC), 100 g of ethanol (c=2.46 J/g.oC), 100 g of carbon tetrachloride (c=0.861 J/g.oC), and 100 g of ethylene glycol (c=2.42 J/g.oC) at 50oC were each placed into a separate coffee cup calorimeter and the temperature recorded. The temperature of the surroundings was 20oC. After one hour the temperature of which substance would have changed by the largest amount? Assume that the rate of heat transfer from the coffee cup to the surroundings was the same in each case.
Calorimetry / Thermochemistry |
Heat Capacity
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Thermochemistry : CalcHBondEnergy (14 Variations)
Use the bond energies given in to estimate the  Ho for the reaction given below:
hint: both carbon dioxide and molecular oxygen have double bonds
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : CalcHCombustion (6 Variations)
Using the thermodynamic data given in  , determine the enthalpy change for the combustion of ethane to produce carbon dioxide and water vapor. 2C2H6(g) + 7O2(g) 4CO2(g) + 6 H2O(g)
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : EnthalpyEnergy (10 Variations)
2SO2(g) + O2(g)2SO3(g)
Horxn = -197.78 kJ
How much energy is transferred when 96.6 g of SO2 reacts to form SO3?
Calorimetry / Thermochemistry |
Chemometrics
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Bonding : EnergyBreakAllBonds (10 Variations)
Use the bond energies given in to determine the total energy needed to break all of the bonds in C3H6. (Do not use ring structures.)
Covalent Bonding |
Calorimetry / Thermochemistry
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Thermochemistry : HeatCapacitySolLiq (4 Variations)
The Table below lists the specific heat capacities of several metals and liquids.
| Substance |
Specific Heat Capacity
J/(g.oC) |
Substance |
Specific Heat Capacity
J/(g.oC) |
| Al |
0.902 |
H2O |
4.18 |
| Fe |
0.451 |
C2H5OH |
2.46 |
| Cu |
0.383 |
CCl4 |
0.861 |
| Au |
0.128 |
CCl2F2 |
0.598 |
In an experiment, 50 g of a metal was heated to 100oC and placed in 200 g of a liquid at 25oC. Which of the following combinations of metal and liquid will produce the largest temperature increase in the liquid? (Assume that there is no transfer of energy to the surroundings.)
Calorimetry / Thermochemistry |
Heat Capacity
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Thermochemistry : CalcHHessLaw (8 Variations)
The industrial process for making sulfuric acid has three steps. Using the data given, calculate the enthalpy change for the overall reaction for the process (the equation is given below).2S(s) + 3O2(g) + 2H2O(l)2H2SO4(l)
Data:
| S(s) + O2(g) SO2(g)
| Hrxn = -296.83 kJ
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| 2SO3(g)O2(g) + 2SO2(g)
| Hrxn = -198.2 kJ
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| SO3(g) + H2O(l)H2SO4(l)
| Hrxn = -227.72 kJ
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Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : MassFromCalorimetry (2 Variations)
The table below lists the specific heat capacities of several metals and liquids. | Substance | Specific Heat Capacity
J/(g.oC) | Substance | Specific Heat Capacity
J/(g.oC) | | Al | 0.902 | H2O | 4.18 | | Fe | 0.451 | C2H5 OH | 2.46 | | Cu | 0.383 | CCl4 | 0.861 | | Au | 0.128 | CCl2F2 | 0.598 |
In an experiment a block of aluminum was heated to 100oC and placed in 200 g of water at 25oC. If the final temperature of the system is 43oC, and no heat transfer to the surroundings occurred, what is the mass of the aluminum block?
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : CalcMolarEnthalpy (5 Variations)
White phosphorus, P4, ignites in air to produce heat, light, and P4O10 according to the following reaction. P4(s) + 5O2(g) P4O10(s) If 67.2 g of P4 is burned,1620 kJ of energy is evolved. What is the molar enthalpy of combustion of P4 if the process was carried out under constant pressure?
Calorimetry / Thermochemistry |
Chemometrics
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Thermochemistry : ConvertEnergyUnits (4 Variations)
The label on a granola bar says it provides 120 Calories. How many kilojoules of energy will this bar provide if it is completely metabolized?
Calorimetry / Thermochemistry |
Nomenclature / Units / Symbols
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Solutions : ConvertConcUnits (10 Variations)
The maximum concentration of arsenic in drinking water that is allowed by the EPA is 0.050 mg/L. Express this as a weight percent. (You can assume the density of the water solution is 1.0g/mL.)
Solutions / Solvents |
Nomenclature / Units / Symbols |
Chemometrics
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Solutions : GramsToMolalSoln (20 Variations)
How many grams of citric acid need to be added to 750 ml of ethanol to make a 0.50 m solution?
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Density (g/ml)
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Molecular Weight (g/mol)
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Citric acid
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1.665
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192.14
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Ethanol
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0.7893
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46.07
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Solutions / Solvents |
Nomenclature / Units / Symbols |
Chemometrics
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Solutions : MixturesMolcPics (11 Variations)
Which of the following combinations of substances corresponds to the molecular scale diagram shown below?
Solutions / Solvents |
Noncovalent Interactions |
Precipitation / Solubility
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Solutions : WtPercentToMolarity (4 Variations)
A common concentration unit used commercially is percent weight per volume (%W/V) which is the number of grams of solute in 100 mL of solution. A bottle of vinegar contains 5 %W/V acetic acid (CH3COOH). What is the molar concentration of acetic acid in the vinegar?
Solutions / Solvents |
Nomenclature / Units / Symbols |
Chemometrics
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Solutions : CalcMolarityFromPPT (10 Variations)
You are given a water sample to analyze from a lake contaminated with lead. It takes 24 mL of 0.020 M NaCl to exactly precipitate the Pb2+ ions from 61 mL of the water sample. What is the concentration of Pb2+ ions in the water?
Pb2+(aq) + 2NaCl(aq) PbCl2(s) + 2Na+(aq)
Solutions / Solvents |
Nomenclature / Units / Symbols |
Chemometrics
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Thermochemistry : PhaseChangeEnthalpy (10 Variations)
A solid melts to a liquid. Which of the following statements are true? (Assume constant pressure and a flexible container.)
Calorimetry / Thermochemistry |
Phases / Phase Transitions / Diagrams
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Thermochemistry : PhaseChanges (8 Variations)
Steam at 100oC is condensed by an ice-water mixture at 0oC. Assuming that there is still ice present when the process is over, how much ice will be melted if 10.0 g of steam is condensed? The following may be useful:
enthalpy of vaporization of water = 40.7 kJ/mol; enthalpy of fusion of water = 6.07 kJ/mol; specific heat capacity of water = 4.184 J/g•K.
Calorimetry / Thermochemistry |
Phases / Phase Transitions / Diagrams
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Intermolecular_Forces__Liquids_and_Solids : PhaseEnergyChanges (6 Variations)
When a liquid is transformed into its vapor at constant temperature,
Phases / Phase Transitions / Diagrams |
Calorimetry / Thermochemistry
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