Chem Exam 3

Determine the concentration of a solution prepared by diluting 20.0 mL of a 0.200 M LiCl to 250.0 mL.

0.0160 M

Which of the following solutions will have the highest electrical conductivity?

0.045 M Al2(SO4)3

How many moles of BCl3 are needed to produce 5.00 g of HCl(aq) in the following reaction? BCl3(g) + 3 H2O(l) → 3 HCl(aq) + B(OH)3(aq)

0.0457 mol

Lithium and nitrogen react to produce lithium nitride:6Li(s) + N2(g) → 2Li3N(s)How many moles of N2 are needed to react with 0.450 mol of lithium?

0.0750

Consider the following balanced reaction. What mass (in g) of CO2 can be formed from 288 mg of O2? Assume that there is excess C3H7SH present.C3H7SH(l) + 6 O2(g) → 3 CO2(g) + SO2(g) + 4 H2O(g)

0.198 g CO2

What is the concentration (M) of a NaCl solution prepared by dissolving 7.2 g of NaCl in sufficient water to give 425 mL of solution?

0.29 M

Two samples of calcium fluoride are decomposed into their constituent elements. The first sample produced 0.154 g of calcium and 0.146 g of fluorine. If the second sample produced 294 mg of fluorine, how many g of calcium were formed?

0.309 g

How many moles of oxygen are formed when 58.6 g of KNO3 decomposes according to the following reaction? The molar mass of KNO3 is 101.11 g/mol.4 KNO3(s) → 2 K2O(s) + 2 N2(g) + 5 O2(g)

0.724 mol O2

How many moles of LiI are required to make 250 mL of a 3.00 M solution?

0.750 moles

What are the correct coefficients (reading from left to right) when the chemical equation is balanced? __PCl5(l)+ __H2O(l)→H3PO4(aq)+__ HCl(aq)

1, 4, 1, 5

Dinitrogen monoxide gas decomposes to form nitrogen gas and oxygen gas. How many grams of oxygen are formed when 30.0 g of dinitrogen monoxide decomposes?

10.9 g

Balance the chemical equation given below, and determine the number of grams of MgO are needed to produce 15.0 g of Fe2O3.________ MgO(s) + ________ Fe(s) → ________ Fe2O3(s) + ________ Mg(s)

11.4 g

If the percent yield for the following reaction is 65.0%, how many grams of KClO3 are needed to produce 42.0 g of O2?2 KClO3(s) → 2 KCl(s) + 3 O2(g)

165 g

How many of the following compounds are insoluble in water?LiC2H3O2 , BaSO4, BaS, AlPO4

2

Which of the following is an acid-base reaction?

2 HClO4(aq) + Ca(OH)2(aq) → 2 H2O(l) + Ca(ClO4)2(aq)

Give the complete ionic equation for the reaction (if any) that occurs when aqueous solutions of lithium sulfide and copper (II) nitrate are mixed.

2 Li+(aq) + S2-(aq) + Cu2+(aq) + 2 NO3-(aq) → CuS(s) + 2 Li+(aq) + 2 NO3-(aq)

Give the theoretical yield, in moles, of CO2 from the reaction of 4.00 moles of C8H18 with 4.00 moles of O2.2 C8H18 + 25 O2 → 16 CO2 + 18 H2O

2.56 moles

What is the concentration (M) of CH3OH in a solution prepared by dissolving 19.6 g of CH3OH insufficient water to give exactly 230 mL of solution?

2.66

Give the percent yield when 28.16 g of CO2 are formed from the reaction of 4.000 moles of C8H18 with 4.000 moles of O2.2 C8H18 + 25 O2 → 16 CO2 + 18 H2O

25.00%

Identify the correct balanced equation for the combustion of pentene (C5H10).

2C5H10(g)+15O2(g)→10H2O(g)+10CO2(g)

How many of the following compounds are soluble in water?Cu(OH)2, LiNO3, NH4Cl, Li2S

3

How many milliliters of a 0.184 M NaNO3 solution contain 0.113 moles of NaNO3?

614 mL

Find the percent by mass of sodium chloride in a 1.40 M NaCl solution. The density of the solution is 1.07 g/mL.

7.65%

Determine the percent yield of aspirin for the reaction.

76.7 %

Determine the percent yield of a reaction that produces 28.65 g of Fe when 50.00 g of Fe2O3 react with excess Al according to the following reaction.Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)

81.93 %

A reaction was conducted between barium nitrate and sodium phosphate. 3 Ba(NO3)2 + 2 Na3PO4 → 6 NaNO3 + Ba3(PO4)2 What is the percent yield if 0.3 mol Ba(NO3)2mol Ba(NO3)2 and 0.25 mol Na3PO4 react to produce 0.095 mol Ba3(PO4)2?

95%

Imagine that A and B are cations and X, Y, and Z are anions, and that the following reactions occur: AX(aq)+BY(aq)→no precipitate AX(aq)+BZ(aq)→precipitate

AZ

Classify these compounds as acid, base, salt, or other.

Acid: HCOOH; HNO3 Base: NaOH; NH3 Salt: NaBr; KCl Other: CH3CH3; CO2

Enter the net ionic equation for the reaction of aqueous sodium chloride with aqueous silver nitrate.

Ag+(aq)+Cl−(aq)→AgCl(s)

Which of the following is NOT a strong electrolyte?

BaCO3

Each of the following compounds is soluble in water. For which compounds do you expect the resulting aqueous solution to conduct electrical current?

BaCl2, CsCl

Which one of the following compounds is insoluble in water?

BaSO4

Enter the chemical formula for the anion present in the aqueous solution of KBr.

Br-

Enter the chemical formula for the anion present in the aqueous solution of Zn(C2H3O2)2

C2H3O2-

Which of the following compounds is not an Arrhenius acid?

CH3NH2

When HNO3 is slowly dropped onto a piece of CaCO3, bubbles appear on the surface of the solid. Which of the following explains this observation?

CO2 gas is formed in the reaction.

Which of the following would you least expect to find in CaCl2(aq)?

CaCl2 molecules.

Which of the following pairs of aqueous solutions will form a precipitate when mixed?

CaS + Na2SO4

Enter the chemical formula for the anion present in the aqueous solution of (NH4)2CO3.

Co3_2-

Which of the following is a strong electrolyte in solution?

FeCl3

Give the formula for sulfurous acid.

H2SO3

Identify the polyprotic acid.

H2SO4

What is the net ionic equation for the reaction that occurs when you mix aqueous solutions of NaHCO3 and HC2H3O2?

HCO3(aq)+HC2H3O2(aq)→CO2(g)+H2O(l)+C2H3O2−(aq)

Which of the following represents a chemical property of hydrogen gas?

It reacts explosively with oxygen.

Enter the chemical formula for the cation present in the aqueous solution of KBr.

K+

The mixing of which pair of reactants will result in a precipitation reaction?

K2SO4(aq)+Pb(NO3)2(aq)

Determine the limiting reactant (LR) and the mass (in g) of nitrogen that can be formed from 50.0 g N2O4 and 45.0 g N2H4. Some possibly useful molar masses are as follows: N2O4 = 92.02 g/mol, N2H4 = 32.05 g/mol.N2O4(l) + 2 N2H4(l) → 3 N2(g) + 4 H2O(g)

LR = N2O4, 45.7 g N2 formed

Insoluble sulfide compounds are generally black in color. Which of the following combinations could yield a black precipitate?

Li2S(aq)+Pb(NO3)2(aq); K2S(aq)+Sn(NO3)4(aq)

Which pair of compounds is soluble in water?

LiI and Ca(NO3)2

Which of the following represents a physical property?

Mercury is a silvery liquid at room temperature.

Enter the chemical formula for the cation present in the aqueous solution of (NH4)2CO3.

NH4+

Enter the chemical formula for the anion present in the aqueous solution of Pb(NO3)2

NO3−

Which one of the following compounds is soluble in water?

Ni(NO3)2

Enter the chemical formula for the cation present in the aqueous solution of Pb(NO3)2.

Pb2+

Identify whether each of the following compounds is soluble or insoluble.

Soluble: Pb(NO3)2; Zn(C2H3O2)2; KBr; (NH4)2CO3 Insoluble: none

When the following two solutions are mixed: K2CO3(aq)+Fe(NO3)3(aq) the mixture contains the ions listed below. Sort these species into spectator ions and ions that react.

Spectator ions: NO3-, K+ Ions that react: Fe3+, CO3_2-

What is the net ionic equation of the reaction of MgSO4 with Sr(NO3)2?

Sr2+(aq)+SO42−(aq)→SrSO4(s)

Write net ionic equations for the formation of each of the precipitates observed.

Sr2+(aq)+SO42−(aq)→SrSO4(s); Cu2+(aq)+CO32−(aq)→CuCO3(s)

Which ions were present in the original solution?

Sr2+; Cu2+

To what volume should you dilute 53 mL of a 12 M stock HNO3 solution to obtain a 0.137 HNO3 solution?

V = 4.6 L

Find the volume of 0.150 M hydrochloric acid necessary to react completely with 1.60 g Al(OH)3.

V= 0.410 L

What volume of a 0.20 M silver nitrate solution is required to precipitate all the Cl− ion in the solution as AgCl?

V= 0.42 L

9.0 g of iron is reacted with 9.0 g of water according to the chemical equation shown below. Which one of the following statements is false?3 Fe(s) + 4 H2O(l) → Fe3O4(s) + 4 H2(g)

Water is the limiting reactant.

Substance X is a molecular compound and is not an acid nor a base. Based just on this information, what can you determine about substance X?

X is not an electrolite.

Enter the chemical formula for the cation present in the aqueous solution of Zn(C2H3O2)2.

Zn2+

What is the net ionic equation of the reaction of ZnCl2 with NaOH?

Zn2+(aq)+2OH−(aq)→Zn(OH)2(s)

0.280 MCa(NO3)2

[NO3−] = 0.560M

0.370 MAl(NO3)3

[NO3−] =1.11 M

0.150 MKNO3

[NO3−]= 0.150 M

Suppose that aqueous solutions of barium nitrate and potassium carbonate are mixed. What is the name of the compound or compounds that precipitate?

barium carbonate

Determine the name for aqueous HBr.

hydrobromic acid

What is the name for an aqueous solution of HIO?

hypoiodous acid

Determine the name for HIO3.

iodic acid

Determine the theoretical yield of aspirin for the reaction.

m = 1.59 g

What mass of CaCl2 (in g) should the chemist use?

m = 230 g

What minimum mass of H2SO4 would you need?

m = 84.5 g

What mass of H2 gas would be produced by the complete reaction of the aluminum block?

m =1.74 g

What mass of hydrochloric acid (in grams) can be neutralized by 2.7 g of sodium bicarbonate? (Hint: Begin by writing a balanced equation for the reaction between aqueous sodium bicarbonate and aqueous hydrochloric acid.)

m= 1.2 g

Determine how many moles of Ba(OH)2Ba(OH)2 are required to completely neutralize 0.428 mol of HC2H3O2.

n = 0.214 mol

133 mL of a 1.78 MKCl solution

n = 0.237 mol

0.612 L of a 2.5 MKCl solution

n = 1.5 mol

1.8 L of a 0.79 MKCl solution

n =1.4 mol

Give the name for HNO3.

nitric acid

Zinc sulfide reacts with oxygen according to the reaction 2ZnS(s)+3O2(g)→2ZnO(s)+2SO2(g) A reaction mixture initially contains 4.8 mol ZnS and 8.5 mol O2. Once the reaction has occurred as completely as possible, what amount (in moles) of the excess reactant remains?

nn = 1.3 mol

A chemical change

occurs when methane gas is burned.

A physical change

occurs when water is evaporated.

Determine the limiting reactant for the reaction.

salicylic acid

Which of the following situations is most favorable for solubility?

strong attraction of solute particles to solvent particles

Give the name for H2SO4.

sulfuric acid

Give your answer as an ordered set of numbers α, β, γ, δ. Your answers should reflect the lowest whole-number ratio of coefficients.

α, β, γ, δ = 2,1,2,1