TIGER

Assessment Questions: 34 results
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
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 : 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 : 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
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 AgOCN used NH4Cl AgCl produced
1 20.4 mL 5.3 mL 2.4 g
2 20.3 mL 10.4 mL 4.3 g
3 20.6 mL 15.4 mL 6.2 g
4 20.5 mL 20.6 mL 8.2 g
5 20.4 mL 25.2 mL 10.2 g
6 20.3 mL 30.4 mL 10.3 g

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 : 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 equation

CH4(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) ArrowZnCl2(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
Solutions : RelativeConc (4 Variations)
What are the relative concentrations of the ions in 0.10 M aqueous sulfuric acid?
Solutions / Solvents |
Stoichiometry
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
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
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