| Assessment Questions: 80 results |
Solutions : RelativeConc (4 Variations)
What are the relative concentrations of the ions in 0.10 M aqueous sulfuric acid?
Solutions / Solvents |
Stoichiometry
|
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
|
Solutions : GeneralSolutions (10 Variations)
You have 500.0mL of 0.100M aqueous MgBr2. Which of the following statements are true?
Solutions / Solvents
|
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
|
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?
|
|
|
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
|
Solutions / Solvents
|
Reactions : PredictRxnProducts (5 Variations)
What are the most likely products from the reaction of aqueous sulfuric acid and aqueous sodium hydroxide?
Aqueous Solution Chemistry |
Reactions
|
Reactions : WillSolnConduct (5 Variations)
One gram of each of the following compounds is mixed with 100mL of water. Which will form solutions that will conduct electricity?
Aqueous Solution Chemistry
|
Reactions : BalanceIonEquation (10 Variations)
What is the balanced net ionic equation for the following reaction:AgNO3(aq) + HCl(aq)  AgCl (s) + HNO3(aq)
Aqueous Solution Chemistry |
Reactions
|
Reactions : Solubility (8 Variations)
Which of the following compounds are soluble in water?
Aqueous Solution Chemistry |
Precipitation / Solubility
|
Solutions : IonConcentration (4 Variations)
Which of the following solutions has the greatest concentration of Na+ ions?
Solutions / Solvents |
Chemometrics
|
Solutions : MassSoluteInSoln (10 Variations)
What is the mass of the solute in 500mL of 0.341M ammonium chloride?
Solutions / Solvents |
Chemometrics
|
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
|
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
|
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
|
Reactions : ExchangeRxn (10 Variations)
Which of the following compounds would result in an exchange reaction if mixed in an aqueous solution with Ba(OH)2?
Aqueous Solution Chemistry |
Reactions |
Precipitation / Solubility
|
Acids_and_Bases : IonizationSteps (20 Variations)
Citric acid (which is a triprotic acid) has the following structure:
Which of the following equations corresponds to the first ionization step of the acid?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : MolcScaleAcidBase (10 Variations)
Study the four drawings below and then decide which best represents an aqueous solution that has
(Water molecules are not shown in the diagrams.)
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : ConjugateAcidBase (20 Variations)
Identify the acid and base that are reactants and the conjugate acid and conjugate base that are products in the following equation:
HI(aq) + H2O(l)  H3O+(aq) + I-(aq)
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : HendersonHassel (20 Variations)
You may want to use the following acid/base table to answer the question below.
Papain is a thiol protease isolated from papaya. The optimal pH for its enzymatic activity is 6.0-7.0. Which of the following buffering systems would work best for a laboratory experiment requiring active papain at pH 6.5? What molar ratios of the compounds would you use to prepare the solution?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
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Acids_and_Bases : IDLewisAcidBase (20 Variations)
Which of the following is a Lewis acid?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : ReactProductFavored (20 Variations)
You may want to use the following acid/base table to answer the question below. Which of the following reactions will be product -favored?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
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Acids_and_Bases : WeakStrongAcidPics (11 Variations)
Which diagram best represents an aqueous solution of HCl? (Water is not shown.) 
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
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Acids_and_Bases : ChooseIndicator (8 Variations)
A 25.0 mL aliquot of a 1.44M solution of ammonia (Kb = 1.8 x 10-5) is titrated with 1.50M HCl. Use the Indicator Table below to decide which of the indicators listed would most accurately signal the equivalence point for this titration. 
Write the letter corresponding to your choice of indicator in the box.
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH
|
Acids_and_Bases : SolnGrams (20 Variations)
How many grams of sodium hydroxide (NaOH) must be dissolved in 510 ml of water to make a solution with a pH = 8.1?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH
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Reactions : IDSampleRxnVideo (7 Variations)
You have an unknown aqueous sample. You add aqueous copper(II) sulfate to the sample. View the video below and determine which of the compounds listed below could be your sample.
Aqueous Solution Chemistry |
Reactions |
Precipitation / Solubility
|
Acids_and_Bases : ProtonTransferRxn (20 Variations)
Write an equation to describe the proton transfer that occurs when the following acid is added to water: HSO4-
Enter the products in the space below using the following as an example:
What ions are present in an aqueous calcium nitrate solution?
Ca(NO3)2(aq) Ca2+(aq) + 2NO3-(aq)
In this case, the answer would be: Ca2+(aq) + 2NO3-(aq)
You should enter: Ca^(2+) + 2NO3^(-)
In other words, use the ^ to indicate superscripts; put charges in parentheses; and leave a space on either side of the + sign. Your answer must be an exact match for the computer to grade it correctly, so be careful.
What products will result when HSO4- is added to water?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
AcidBaseProducts (10 variations)
The following acid/base table may be useful in answering the question below. What products will result when HSO4- is added to water? Complete and balance the reaction below. HSO4- + H2O ?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : AcidBaseProperties (10 Variations)
Which of the following are properties of HCl?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
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Acids_and_Bases : AcidicOrBasicSalt (20 Variations)
When dissolved in an aqueous solution, which of the following salts will yield an acidic solution?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry
|
Acids_and_Bases : PercentDissociationKa (3 Variations)
Calculate the percent dissociation in a {x}M aqueous solution of the weak acid HA. (Ka = {y} x 10-4)
Enter your answer to ONE decimal place.
DO NOT use scientic notation.
DO NOT write in the units.
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
Equilibrium
|
Acids_and_Bases : TitrationCurveKaKb (8 Variations)
Study the graph of the titration of a weak acid with a strong base shown below. What is the approximate Ka for this acid? 
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
Titration / Volumetric Analysis
|
Acids_and_Bases : LewisAcidBaseRxns (19 Variations)
Identify the Lewis Acid and Base in the reaction of Ag+ and NH3 to form Ag(NH3)2+
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
Lewis Acids / Bases
|
Acids_and_Bases : PracticalAcidBase (20 Variations)
Which of the following statements is true?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
Physical Properties
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Acids_and_Bases : WaterAutoIonization (20 Variations)
What effect will the addition of H2CO3 have on the autoionization of water?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
Water / Water Chemistry
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Acids_and_Bases : WeakAcidSolnpH (20 Variations)
Given an aqueous solution of 0.30 M acetic acid (Ka = 1.8 x 10-5), the pH is approximately ...
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
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Acids_and_Bases : BufferingCapacity (20 Variations)
If a buffer is prepared using 0.75 mol CH3COOH and 0.45 mol CH3COO- in 1 liter of aqueous solution, is the buffering capacity of the solution great enough to maintain its pH if 10 g NaOH is added?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
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Acids_and_Bases : pHDilution (6 Variations)
What is the pH of a solution made by diluting {x} mL of {y} M HNO3(aq) to a total volume of 500 mL?
Enter your answer to two decimal places.
DO NOT use scientific notation
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
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Acids_and_Bases : pHBufferCalc (4 Variations)
Calculate the pH of a buffer solution containing {x}M NH3 and {y}M NH4NO3.
Enter your answer to TWO decimal places.
DO NOT use scientific notation.
DO NOT enter units
eg: 4.55
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
|
Acids_and_Bases : BufferWeakStrong (7 Variations)
How many mL of a 2.50 M HCl solution must be added to 500 mL of a 0.150 M CO32- solution to make a buffer with pH = 10.00?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
|
Acids_and_Bases : CalcSolnpH (5 Variations)
Use this acid/base table to answer the question below.
Calculate the pH of a {x}M sodium acetate solution.
DO NOT use scientific notation
Enter your answer to two decimal places.
DO NOT enter units
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
|
Acids_and_Bases : BufferWeakWeak (14 Variations)
What mass of potassium bicarbonate (KHCO3) must be added to 500 mL of a 0.200 M carbonic acid solution to make a buffer with pH = 6.30?
Acids / Bases |
Reactions |
Aqueous Solution Chemistry |
pH |
Equilibrium
|
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
|
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
|
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
|
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
|
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
|
Stoichiometry : GramMoleProblem (9 Variations)
Which sample contains the largest number of nitrogen atoms?
Stoichiometry
|
Stoichiometry : StoicNeeds (10 Variations)
You have a known mass of a compound X and react it to form compound Y. What is the minimum information you need to find the mass of Y produced?
Stoichiometry
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Atoms,_Molecules_and_Ions : MassInAlloy (10 Variations)
Gold is alloyed with other metals to make it less malleable. 10 karat gold is an alloy that is 41.7% gold. How much pure gold is in a 20. gram 10 karat gold ring?
Stoichiometry
|
Stoichiometry : LimitingReagent (8 Variations)
The synthesis of urea by Frederich W??hler in 1825 began the decline of the idea that "organic" chemicals could only be made by living organisms as part of their biological processes. AgOCN(aq) + NH4Cl(aq) AgCl(s) + NH2CONH2(aq) If you perform this reaction and collect the following table of data, in which trial(s) is AgOCN clearly the limiting reactant?
| Trial
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AgOCN used
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NH4Cl
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AgCl produced
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| 1
|
20.4 mL
|
5.3 mL
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2.4 g
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| 2
|
20.3 mL
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10.4 mL
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4.3 g
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| 3
|
20.6 mL
|
15.4 mL
|
6.2 g
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| 4
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20.5 mL
|
20.6 mL
|
8.2 g
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| 5
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20.4 mL
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25.2 mL
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10.2 g
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| 6
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20.3 mL
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30.4 mL
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10.3 g
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The mL of AgOCN and NH4Cl are the initial amounts used, the mass of AgCl is how much was recovered from the reaction. (Hint: You do not need to do any calculations to answer this question.)
Stoichiometry
|
Gases : VolGasReactInTorch (10 Variations)
Oxyacetylene torches used in high-temperature welding use a combination of oxygen and acetylene. The combustion of acetylene (C2H2) occurs in these torches. What volume of oxygen is needed to react with 250 mL of acetylene?
Gases |
Stoichiometry
|
Stoichiometry : CalcPercentYield (8 Variations)
When copper is heated in air, copper(II) oxide is formed. In a given experiment, 1.50 g copper was heated to yield 1.76 g copper(II) oxide. What is the percent yield?
Stoichiometry |
Chemometrics
|
Stoichiometry : CalcWeightPercent (8 Variations)
What is the weight percent of oxygen in LiHCO3?
Stoichiometry |
Chemometrics
|
Stoichiometry : EmpirFormulaFromRxn (10 Variations)
When one mole of a diatomic gas, Y2(g), reacts with one mole of hydrogen gas, neither gas is left over. What is the empirical formula of the compound formed?
Stoichiometry |
Reactions
|
Stoichiometry : GeneralMassMole (4 Variations)
10.0 g of nitrogen monoxide is reacted with 10.0 g of oxygen to form nitrogen dioxide. Which of the following statements is true?
Stoichiometry |
Reactions
|
Stoichiometry : RxnNanoPics (4 Variations)
The following diagram shows a compound reacting to form products. Which equation best describes the stoichiometry of the reaction shown in the diagram?
Stoichiometry |
Reactions
|
Stoichiometry : BalanceRxn (14 Variations)
The reaction of methane with oxygen has the following unbalanced equationCH4(g) + O2(g) CO2(g) + H2O(l) The coefficient for oxygen in the balanced equation is ...
Stoichiometry |
Reactions
|
Stoichiometry : DiagramRxnProds (6 Variations)
According to the law of conservation of matter, which of the following diagrams represents possible products of the following reaction?
A2 + 2B2
Stoichiometry |
Reactions
|
Stoichiometry : CalcTheorYield (10 Variations)
If you react 6.2g of phosphine with 8.30g of oxygen, what is the theoretical yield of phosphorous pentaoxide?
4PH3 + 8O2 P4O10 + 6H2O
Stoichiometry |
Chemometrics
|
Stoichiometry : DeterMolesInRxn (4 Variations)
The reaction of zinc with aqueous hydrochloric acid has the following unbalanced equation Zn(s) + HCl(aq) ZnCl2(aq) + H2(g) When 0.1 moles of zinc is reacted with 0.1 moles of hydrochloric acid ...
Stoichiometry |
Reactions
|
Stoichiometry : TheorYieldDeviation (10 Variations)
You reacted a known amount of phosphorous triiodide with excess water and determined that the percent yield of phosphoric acid was less than 100%, which of the following statements could explain why?
PI3 + 3H2O H3PO3 + 3HI
Stoichiometry |
Reactions
|
Stoichiometry : CalcWtPercent (6 Variations)
A standard dose of antacid as a calcium supplement is two tablets. The active ingredient in many of these tablets is calcium carbonate. One tablet, having a weight of 1.415 g, is reacted with excess HCl(aq) to produce 0.22 g CO2. What is the weight percent of calcium in this tablet? CaCO3(s) + 2HCl(aq)CaCl2(aq) + H2O(l) + CO2(g)
Stoichiometry |
Chemometrics
|
Stoichiometry : CalcPercentPurity (4 Variations)
To test the purity of calcium sulfate, you dissolve a 4.56g sample in water and add oxalic acid to precipitate out calcium oxalate. If 3.45g of precipitate forms, what is the percent purity of the calcium sulfate?
CaSO4(aq) + H2C2O4(aq) CaC2O4(s) + H2SO4(aq)
Stoichiometry |
Chemometrics
|
Stoichiometry : AtomsAndGrams (10 Variations)
How many moles of atoms does a 500. g bar of gold contain?
Stoichiometry |
Nomenclature / Units / Symbols
|
Stoichiometry : CombustionAnalysis (10 Variations)
While working in the lab, you find a bottle of white powder labeled
"analgesic compound #5". Since the original investigator neglected
to record the identity of the substance, you decide to perform a
combustion analysis to identify the compound. You have a 65.7 g
sample that when burned produces 182 g CO2 and 51.7 g
H2O. What is the formula of this compound? (The compound
only consists of C,H, and O.)
Stoichiometry |
Molecular Properties / Structure
|
Stoichiometry : ExplainYldError (4 Variations)
Your TA gives you an aqueous solution containing an unknown quantity of AgNO3(aq) and an unknown quantity of Mg(NO3)2(aq). You are asked to determine the molarity of Ag+ in the solution. You add HCl(aq) to your unknown to precipitate the silver as AgCl(s), then filter out the precipitate, dry it, weigh it, and calculate the concentration of silver ion. However, your TA tells you that your calculated value of [Ag+(aq)] is lower than the actual value. Which of the following could account for your answer being too low? There may be more than one correct answer.
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : FormulaFromComp (8 Variations)
Lactic acid is the substance that makes your muscles burn when you've been exercising hard. Lactic acid is composed of 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by weight. If it has a molar mass of 90 g/mol, what is its molecular formula?
Stoichiometry |
Molecular Properties / Structure
|
Stoichiometry : PrecipYield (3 Variations)
In a laboratory experiment to determine accurately the amount of barium in solution, aqueous sulfuric acid was added to the solution to precipitate barium sulfate, which was then filtered and weighed. In this experiment it is MOST important that ...
Stoichiometry |
Reactions |
Chemometrics
|
Bonding : DetermineStructure (8 Variations)
H
A substance is analyzed and found to contain 57.10% carbon, 4.80% hydrogen and 38.06% oxygen by weight. Its molecular weight is determined to be 126.11 g/mol. Which of the structures shown are possible structures for the substance?
Molecular Properties / Structure |
Stoichiometry
|
Atoms,_Molecules_and_Ions : AtomicRatio (10 Variations)
Which compound(s) contain the most nitrogen atoms per molecule or formula unit?
Molecular Properties / Structure |
Stoichiometry
|
Atoms,_Molecules_and_Ions : BinaryMolcFromImage (8 Variations)
Which of the following binary compounds could the figure below best represent? 
Molecular Properties / Structure |
Stoichiometry
|
Atoms,_Molecules_and_Ions : IonicFormula (10 Variations)
Which pair of ions will form a compound of formula M2X?
Molecular Properties / Structure |
Stoichiometry
|
Atoms,_Molecules_and_Ions : CalcMolarMass (8 Variations)
What is the molar mass of potassium phosphate,
K3PO4?
Enter the numeric value very carefully below, rounding to one decimal place only. Do not put the units in, but think about what the
units are!
Molecular Properties / Structure |
Stoichiometry
|
Stoichiometry : GivenYieldCalcStMat (4 Variations)
Calcium oxide and water are produced by heating calcium hydroxide. If the reaction has an expected yield of 60%, how much calcium hydroxide should be reacted to produce 115g of calcium oxide?
Ca(OH)2 CaO + H2O
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : MolsO2ToReactFuel (10 Variations)
Butane can be used as a fuel. How many moles of oxygen are needed to completely react with 3.0 moles of butane?
The unbalanced reaction equation is given below:
C4H10(g) + O2(g) CO2(g) + H2O(g)
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : RxnMolsProduced (8 Variations)
Given the following balanced chemical reaction:
4A + 3B2 2A2B3
If 12 moles of A are reacted with excess B2, how many moles of A2B3 will be produced?
Very carefully enter the number below.
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : GivenMassCalcStMat (10 Variations)
Aspirin is a common analgesic. If you want to produce 250. mg of aspirin (C9H8O4) from the reaction of C7H6O3 and C4H6O3, what is the minimum amount of C7H6O3 that is needed? 2C7H6O3(s) + C4H6O3(l) 2C9H8O4(s) + H2O(l)
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : RxnTable (10 Variations)
Iron reacts with oxygen to form iron(III) oxide according to the following reaction.
4Fe(s) + 3O2(g)2Fe2O3(s)
|
Fe(s)
|
O2(g)
|
Fe2O3(s)
|
| Initial Amount
|
-
|
-
|
-
|
| Change
|
-
|
-
|
-
|
| End Amount
|
-
|
-
|
-
|
Complete the reaction table for a reaction mixture containing 12.0 moles of iron and 10.0 moles of oxygen, and select the true statement(s) from following list.
Stoichiometry |
Reactions |
Chemometrics
|
Stoichiometry : SolnStoich (4 Variations)
You are working in a forensic lab and are given a blood sample from a suspected drunk driver and asked to determine the person's blood alcohol level. The legal limit is 0.08% by mass in most states. You use the following reaction in your determination, assuming only the ethanol (C2H5OH) in the blood sample will react with the dichromate.
16H+(aq) + 2Cr2O72-(aq) + C2H5OH(l)4Cr3+(aq) + 11H2(l) + 2CO2(g)
If 14.6 mL of 0.10 M K2Cr2O7 are needed to react completely with 28 g of blood, what is the blood alcohol level of the driver?
Stoichiometry |
Reactions |
Chemometrics
|
