Chemistry 120       Problem Session 2

 

1.     Give the correct IUPAC names for the following compounds

a.                      Na2SO4  sodium sulfate            

b.                      Mg3(PO3)2  magnesium phosphite

c.                      PF5   phosphorous pentafluoride           

d.                      MnO    manganese(II) oxide                 

e.                      Ti(IO4)3 titanium(III) periodate  

f.                       Ag2S      silver sulfide               

g.                      (NH4)2SeO3     ammonium selenite

h.                      Zn(BrO)2            zinc hypobromite

i.                       Cu(NO3)2           copper(II) nitrate

j.                       NO2        nitrogen dioxide         

k.                      (NH4)2CrO4 ammonium chromate

l.                       Pb(ClO3)2           lead(II) chlorate

m.                    Ca(NO3)2           calcium nitrate

n.                      K3PO4    potassium phosphate  

o.                      LiOH      lithium hydroxide       

p.                      AgC2H3O2           silver acetate 

q.                      Al(MnO4)3aluminum permanganate

r.                       CuCr2O7 copper(II) dichromate 

s.                      Cd(CN)2 cadmium cyanide        

t.                       BaCO3                barium carbonate

u.                      ZnC2O4  zinc oxalate                 

v.                      RbClO4  rubidium perchlorate  

w.                    Sr(BrO3)2           strontium bromate

x.                       Ni(HSO4)2 nickel (II) hydrogen sulfate

y.                      H3PO4    phosphoric acid          

z.                       Mg(H2PO4)2  magnesium dihydrogen phosphate

aa.                    Hg2(NO2)2           mercury(I) nitrite

bb.                   Fe(IO2)2 iron(II) iodite              

cc.                    CS2         carbon disulfide          

dd.                   CrBr3      chromium(III) bromide

ee.                    HC2H3O2           acetic acid       

ff.                     HBr(aq) hydrobromic acid       


2.     Write the correct formula for the following compounds

a.     Potassium arsenate         K3AsO4

b.     Vanadium(III) chlorate   V(ClO3)3

c.     Calcium carbonate          CaCO3

d.     Carbon tetrabromide       CBr4   

e.     Cadmium sulfite             CdSO3

f.      Sulfur dioxide    SO2                

g.     Tungsten(II) nitride        W3N2  

h.     Sodium acetate   NaC2H3O2      

i.      Stannous fluoride           SnF2   

j.      Chromium(III) nitrite     Cr(NO2)3

k.     Chromium(III) acetate Cr(C2H3O2)3

l.      Iodous acid         HIO2(aq)

m.   Potassium sulfite            K2SO3

n.     Ammonium oxalate        (NH4)2C2O4

o.     Dichlorine heptoxide      Cl2O7  

p.     Aluminum hydroxide     Al(OH)3

q.     Sodium hydrogen sulfate NaHSO4

r.      Mercury(II) phosphate   Hg3(PO4)2

s.     Hydrocyanic acid           HCN(aq)

t.      Tin(IV) sulfide   SnS2               

u.     Zinc dihydrogen phosphateZn(H2PO4)2

v.     Iodine trichloride            ICl3     

w.   Cobalt(III) chromate       Co2(CrO4)3

x.     Lead(IV) oxide               PbO2  

y.     Bismuth(III) cyanide      Bi(CN)3

z.     Iron(III) nitrate   Fe(NO3)3        

aa.   Calcium bicarbonate       Ca(HCO3)2

bb.  Uranium(VI) fluoride     UF6    

cc.   Magnesium perchlorate  Mg(ClO4)2

dd.  Arsenic acid       H3AsO4          

ee.   Lithium borate    Li3BO3                       

ff.    Silver sulfate      Ag2SO4          


 

3.     For the amino acid valine, C5H11O2N, calculate

a.     Molecular mass 

 

5mol C(12.01g/mol) + 11mol H(1.008g/mol) + 2 mol O(16.00g/mol) + 1 mol N(14.00g/mol) =117.16 g/mol

 

b.     Mass of 2.434 mol valine          

c.     Number of moles in 34.22 g valine       

 

d.     Number of moles H in 2.83 moles valine          

 

e.     Number moles O in a sample of valine containing 3.22 moles H          

f.      Number of molecules of valine in a 3.09 mol sample of valine 

 

g.     Mass of carbon in a 2.48 mole sample of valine           

 

h.     Number of atoms of hydrogen in a 6.40 g sample of valine      

6.40g C5H11O2N x 1 mol C5H11O2N x 5 mol H           x 6.02 x 1023 Hatoms  = 3.29 x 1022

                                    117.16 g                1 mol C5H11O2N

i.      Mass of valine that contains 3.29 x 1025 atoms of carbon         


j.      Mass in grams of one valine molecule  

k.     Percent composition       51.25%C, 9.46%H, 27.31%O, 12.26%N

 

4.     Determine an the empirical formula for each of the following sets of percent composition data

a.     43.64% P, 56.36% O    

b.     72.03% Mn, 27.97% O

 

c.     87.73% C, 12.27% H    

            


d.     77.27% Hg, 9.25% C, 1.17% H, 12.32% O     

   

 

5.     Find the molecular formula of a compound composed of 91.25% carbon and 8.75% hydrogen, which has a molar mass of 184 g/mol.


6.     A 14.1 mg sample of a hydrocarbon was burned in air.  The products were 38.8 mg of CO2 and 31.7 mg of water.  What is the empirical formula of the hydrocarbon?

 

Note that we can use mmoles here to avoid working with very small numbers.  Also notice that we were told there was only H and C so we did not need to figure out the oxygen moles.
 

 

 

7.     Rounded Rectangular Callout: This is a hard problem!!A 0.2417 gram sample of a compound known to be composed of C, H, O and Cl only, is burned in oxygen yielding 0.4964 grams of carbon dioxide and 0.0846 grams of water.  A separate 0.1696 gram sample of the compound is fused with sodium metal, the products dissolved in water and the chloride quantitatively precipitated with silver nitrate to yield 0.1891 grams of AgCl.  What is the simplest empirical formula for the compound?


 


 

 


 

 



 


8.     Balance the following equations and classify the reaction by type (i.e. decomposition etc.)

Reaction type

a.         C6H12  +      HCl  ˆ      C6H13Cl                               combination or synthesis

b.       2 HI  ˆ      H2  +      I2                                                            decomposition or redox         

c.       2 FeCl3  +   3 Na2CO3  ˆ      Fe2(CO3)3  +  6  NaCl   double displacement or precipitation

d.         H3AsO4  +   3 NaOH  ˆ      Na3AsO4  +  3  H2O    neutralization or acid-base or double displacement

e.       C8H18O  +   12 O2  ˆ  8 CO2  +  9 H2O                     combustion or redox              

f.        2  Cu  +      O2  ˆ  2  CuO                                          combination or redox             

g.       2  HgO  ˆ   2 Hg  +      O2                                         decomposition or redox         

h.       2  H2O  ˆ    2 H2  +      O2                                          decomposition or redox         

i.          BaCl2  +      Na2S  ˆ      BaS  +  2 NaCl                   double displacement or precipitation  

j.         2 Na  +   2 H2O  ˆ   2  NaOH  +      H2                    single replacement or redox    

k.       3 PbO  + 2  NH3  ˆ    3  Pb  +      N2  +    3  H2O

l.        2  NH3  +   3  O2  +    2  CH4  ˆ   2   HCN  +    6  H2O

m.     2 C5H10O2  +  13 O2  ˆ  10 CO2  +  10 H2O              combustion or redox              

9.     Complete and balance the following single and double displacement reactions.  Write total ionic and net ionic equations for each of the reactions.  Use the activity series in your book to predict whether or not the single replacement reactions will occur.

a.     ZnS(s)  +  HCl(aq)

ZnS(s)  +  2 HCl(aq) ˆ ZnCl2(aq)  + H2S(aq)           (H2S is a weak acid and does not dissociate)

ZnS(s)  +  2H+(aq) + 2Cl-1(aq) ˆ Zn+2(aq)  +  2Cl-1(aq)  +  H2S(aq)

ZnS(s)  +  2H+(aq) + ˆ Zn+2(aq)  +  H2S(aq)

                                       

b.     Na2CO3(aq)  +  BaCl2(aq)

Na2CO3(aq)  +  BaCl2(aq) ˆ 2NaCl(aq) + BaCO3(s)

2Na+(aq) + CO3-2(aq) + Ba+2(aq) + 2Cl-1(aq) ˆ 2Na+(aq) + 2Cl-1(aq) + BaCO3(s)

CO3-2(aq) + Ba+2(aq) ˆ BaCO3(s)

 

c.     Na3PO4(aq)  +  HBr(aq)

Na3PO4(aq)  +  3 HBr(aq) ˆ 3NaBr(aq) + H3PO4(aq)          H3PO4 is a weak acid

3Na+(aq) + PO4-3(aq) + 3H+(aq) + 3Br-1(aq) ˆ 3Na+(aq) + 3Br-1(aq) + H3PO4(aq)

PO4-3(aq) + 3H+(aq) ˆ + H3PO4(aq)

 

d.     Ba(OH)2(aq) + HCl(aq)

Ba(OH)2(aq) + 2 HCl(aq) ˆ BaCl2(s) + 2 H2O(l)

Ba+2(aq) + 2OH-1(aq) + 2 H+(aq) + 2Cl-1(aq) ˆ BaCl2(s) + 2 H2O(l) 

Ba+2(aq) + 2OH-1(aq) + 2 H+(aq) + 2Cl-1(aq) ˆ BaCl2(s) + 2 H2O(l) 

 

e.     Sr(C2H3O2)2(aq)  +  NiSO4(aq)

Sr(C2H3O2)2(aq)  +  NiSO4(aq) ˆ SrSO4(s) + Ni(C2H3O2)2(aq)

Sr+2(aq) + 2C2H3O2-1(aq) + Ni+2(aq) + SO4-2(aq) ˆ SrSO4(s) + Ni+2(aq) + 2C2H3O2-1(aq)

Sr+2(aq) + SO4-2(aq) ˆ SrSO4(s)

 

f.      ZnSO3(aq)  +  HCl(aq).

ZnSO3(aq)  +  2 HCl(aq) ˆ H2SO3(aq) + ZnCl2(aq) ˆ H2O(l) + SO2(g) + ZnCl2(aq)

Zn+2(aq) + SO3-2(aq) + 2H+(aq) + 2Cl-(aq) ˆ H2O(l) + SO2(g) + Zn+2(aq) + 2Cl-(aq)

SO3-2(aq) + 2H+(aq) ˆ H2O(l) + SO2(g)

 

g.     Pb(NO3)2(aq)  +  H2S(aq)

Pb(NO3)2(aq)  +  H2S(aq) ˆ PbS(s) + 2HNO3(aq)

Pb+2(aq) + 2NO3-1(aq) + 2H2S(aq) ˆ PbS(s) + 2H+(aq) + 2NO3-1(aq)

Pb+2(aq) + 2H2S(aq) ˆ PbS(s) + 2H+(aq)

 

h.     Fe(OH)3(s)  +  HClO4(aq)

Fe(OH)3(s)  + 3 HClO4(aq) ˆ Fe(ClO4)3(aq) + 3 H2O(l)  (perchlorates generally soluble)

Fe(OH)3(s)  + 3H+(aq) + 3ClO4-1(aq) ˆ Fe+3(aq) + 3ClO4-1(aq) + 3 H2O(l) 

Fe(OH)3(s)  + 3H+(aq) ˆ Fe+3(aq) + 3 H2O(l) 

                                                                  

i.      H2SO4(aq)  +  BaCl2(aq)

H2SO4(aq)  +  BaCl2(aq) ˆ BaSO4(s) + 2 HCl(aq)

2H+(aq) + SO4-2(aq) + Ba+2(aq) + 2Cl-1(aq) ˆ BaSO4(s) + 2H+(aq) + 2Cl-1(aq)

SO4-2(aq) + Ba+2(aq) ˆ BaSO4(s)

 

j.      NaCl(aq)  +  (NH4)2SO4(aq) ˆNR

 

k.     AgNO3(aq)  +  Na2CO3(aq)

2 AgNO3(aq)  +  Na2CO3(aq) ˆ Ag2CO3(s) + 2 NaNO3(aq)

2Ag+(aq) + 2NO3-1(aq) + 2Na+(aq) + CO3-2(aq) ˆ Ag2CO3(s) + 2Na+(aq) + 2NO3-1(aq)

2Ag+(aq) + CO3-2(aq) ˆ Ag2CO3(s)

 

l.      KOH(aq)  +  HNO3(aq)

KOH(aq)  +  HNO3(aq) ˆ KNO3(aq) + H2O(l)

K+(aq) + OH-(aq) + H+(aq) + NO3-1(aq) ˆ K+(aq) + NO3(aq) + H2O(l)

OH-(aq) + H+(aq) ˆ H2O(l)

 

m.   Al(s)  +  NiCl2(aq)

2 Al(s)  +  3 NiCl2(aq) ˆ 3 Ni(s) + 2 AlCl3(aq)

2 Al(s)  +  3 Ni+2(aq) + 2Cl-1(aq) ˆ 3 Ni(s) + 2Al+3 + 3Cl-1(aq)

2 Al(s)  +  3 Ni+2(aq) ˆ 3 Ni(s) + 2Al+3

n.     Ag(s)  +  Pb(NO3)2(aq) ˆ NR                          Pb more active than Ag, no reaction.

 

o.     Cr(s)  +  NiSO4(aq)

Cr(s)  +  NiSO4(aq) ˆ CrSO4(aq) + Ni(s)

Cr(s)  +  Ni+2(aq) + SO4-2(aq) ˆ Cr+2(aq) + SO4-2(aq) + Ni(s)

Cr(s)  +  Ni+2(aq) ˆ Cr+2(aq) + Ni(s)

 

p.     Mn(s)  +  HBr(aq)

Mn(s)  +  2 HBr(aq) ˆ MnBr2(aq) + H2(g)

Mn(s)  +  2 H+(aq) + 2 Br-1(aq) ˆ Mn+2(aq) + 2 Br-1(aq) + H2(g)

Mn(s)  +  2 H+(aq) ˆ Mn+2(aq) + H2(g)

 

q.     H2(g)  +  CuCl2(aq)

H2(g)  +  CuCl2(aq) ˆ2 HCl(aq)  +  Cu(s)

H2(g)  +  Cu+2(aq) + 2 Cl-1(aq) ˆ2 H+(aq) + 2 Cl-1(aq)  +  Cu(s)

H2(g)  +  Cu+2(aq) ˆ2 H+(aq) +  Cu(s)

 

r.      Ba(s)  +  H2O(l)

Ba(s)  +  H2O(l)  ˆ  Ba(OH)2(s) + H2(g)