CHEM 111 Midterm: CHEM 111 EXAM 2

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13 Jun 2018

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1.Which of the following are soluble in water?

a.PbCl2 -NOT SOLUBLE BC PB+2 IS AN EXCEPTION

b. CaCO3-INSOLUBLE

c. NH4Cl-SOLUBLE

2.In an aqueous solution, ________________ is added to a mixture of NaNO3

and Ba(NO3)2. If the barium would precipitate (INSOLUBLE SOLID) but the

sodium remained in solution, what was added?

a.CaCl2-NaCl-soluble, BaCl2-soluble

b.CaCO3-Na2Co3-soluble BaCl2-insoluble

c.Ca(OH)2-NaOH-soluble Ba(OH)2-soluble

Net Ionic Equations

Step 1: Write a balanced chemical equation for the precipitation reaction.

Step 2: Identify all soluble compounds in the reaction and write them in their

ionized form.

Step 3: Identify the spectator ions in the reaction

Step 4: Remove spectator ions and write the reaction using the only species that

remain.

3.Write the net ionic equation between calcium nitrate and sodium

carbonate.Ca(NO3)2(aq) + Na2CO3(aq) → CaCO3(s) + 2 NaNO3(aq)

Ca2+ (aq) + 2NO3- (aq) + 2Na+ (aq) + CO3-2 (aq) → CaCO3 (s) + 2Na (aq) + 2NO3-

(aq)

SPECTATOR ION: Na+, NO3-

Ca+2 (aq) + CO3-2 (aq) → CaCO3 (s)

4.Write the net ionic equation between potassium hydroxide and phosphoric acid.

3 KOH (aq) +H3PO4(aq) DOESN’T MEAN IT’S SOLUBLE JUST BC ITS AQ → 3 H2O

(l) + K3PO4(aq)

3K+ (aq) + 3(OH)- (aq) + H3PO4 (aq) → 3H2O (l) + 3K+ (aq) + PO4 (aq)

SPECTATOR IONS: 3K+

3(OH)- (aq) + H3PO4 (aq) → 3H2O (l) + PO4 (aq)

Oxidation–Reduction

5.Given the reaction Zn (s) (OXIDATION #=0 B/C IT’S JUST BY ITSELF) + 2Cu(NO3)2

(OX. #= -1 B/X (3*(-2) +5=-1) → Zn (ON=2) (NO3)2 (ON=-1)(aq) (OX. #=-1)+ Cu (s)

(ON=0)

a.What is the reducing agent? (GAINS ELECTRONS, becoming more (+)) Zn b/c it

goes from the 0 charge to the +2 charge so it’s losing e- and getting oxidized

b.What is the oxidizing agent? (LOSES E-, becoming more(-)) Cu(NO3)2 b/c it gains

c.What are the two half reactions? Zn b/c it’s losing 2 e- and so you go from a

charge of 0 to +2

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Document Summary

1. which of the following are soluble in water? a. pbcl2 -not soluble bc pb+2 is an exception: caco3-insoluble, nh4cl-soluble. 2. in an aqueous solution, ________________ is added to a mixture of nano3 and ba(no3)2. If the barium would precipitate (insoluble solid) but the sodium remained in solution, what was added? a. cacl2-nacl-soluble, bacl2-soluble b. caco3-na2co3-soluble bacl2-insoluble c. ca(oh)2-naoh-soluble ba(oh)2-soluble. Step 1: write a balanced chemical equation for the precipitation reaction. Step 2: identify all soluble compounds in the reaction and write them in their ionized form. Step 3: identify the spectator ions in the reaction. Step 4: remove spectator ions and write the reaction using the only species that remain. 3. write the net ionic equation between calcium nitrate and sodium carbonate. ca(no3)2(aq) + na2co3(aq) caco3(s) + 2 nano3(aq) Ca2+ (aq) + 2no3- (aq) + 2na+ (aq) + co3-2 (aq) caco3 (s) + 2na (aq) + 2no3- (aq) Ca+2 (aq) + co3-2 (aq) caco3 (s) 4. write the net ionic equation between potassium hydroxide and phosphoric acid.

Related Questions

1. Balance each equation:

a) H2 +I2 = HI b) Al+O2 = Al2O3 d) Al+HBr = Albr3+H2

2. Calcium oxide is prepared by heating limestone (calcium carbonate, CaCO3) to a high temperature, at point it decomposes to calcium oxide and carbon dioxide. Write a balanced equation for this preparation of calcium oxide.

3.When a piece of aluminum metal is dropped into hydrochloric acid, HCI, hydrocloric acid, HCI, hydrogen is released as a gas and a solution of aluminum chloride forms. Write a balanced equation for the reaction.

4. In the equation: 2Na^+(aq)+CO3^2-(aq)+Sr^2+(aq)+2CI^-(aq)+SrCO3(s)+2Na^+(aq)+2CI^-(aq)

a) Identify the spectator ions b) Write the balaanced net ionic equation

5. When a solution of sodium hyroxide is added to a solution of ammonium carbonate, H2O is formed and ammonia gas, NH3, is released whe the solution is heated. Write a net ionic equation for this reaction. Both NaOH and (NH4)2CO3 exist as dissociated ions in aqueous solution.

6. Using the solubility generalizations given in Section 4-3 predict which of these ionic compounds are soluble in water.

a)MgCl2 b)CaCO3 c)Na2SO3 d)NH4NO3 e)Pb(OH)2

7. When a piece of sodium metal is added to water, hydrogen is evolvedas a gas . and a solution of sodium hydroxide is formed.

a) Write a balanced equation for this reaction.

b) What is oxidized in this reaction? What is reduced?

8. Calculate the formula weight of:

a)Na3PO4 b)Al2(SO4)3

9. Calculate the number of moles in:

a) 32g of methane,CH4 b)184.4g of chlorine dioxide ClO2

10. Calculate the number of grams in:

a) 1.77 mol of nitrogen dioxide, NO2 b) 3.69 mol of uranium hexaflouride, UF6

1. A 15.00 mL sample of perchloric acid, HClO4(aq) was titratedwith 1.385 M sodium hydroxide, NaOH (aq) to a phenolphthalein endpoint. The volume of base solution used is 22.25 mL.
a) Write a balanced molecular equation
b) Identify the spectator ions
c) Write a net ionic equation for this neutralization.
d) Calculate the molarity of the perchloric acid.

2. Consider using 0.445 M hydroiodic acid, HI(aq) to completelyneutralize 12.5 mL of 0.225 M Ba(OH)2(aq).
a) Write a balanced molecular equation
b) Identify the spectator ions
c) Write a net ionic equation for this neutralization.
d) How many mL of 0.445 M HI(aq) would be needed for thisneutralization?

3. An aqueous solution of sulfuric acid is neutralized by anaqueous solution of the base, lithium hydroxide. Write a balancedmolecular equation showing this chemical reaction. Be sure toinclude physical states.

I VALUE QUALITY RATHER THAN TIME