Quiz 7 Name: _______________________________________ Chemistry 102, Lecture 402 – Fall 2016 DS Section: (1 point) ____________________________ 1. What is one metal that will react with lead(II) nitrate? There are many answers which are stronger reducing agents than Pb(s); we will use magnesium here. Complete the table below for this reaction. (6 points) Balanced equations Macroscopic/Particle representation Oxidation half‐reaction: Mg(s)  Mg2+(aq) + 2e– Reduction half‐reaction: NO3 Pb2+(aq) + 2e–  Pb(s) –
–
Also fine: Pb(NO3)2(aq) + 2e  Pb(s) + 2NO3 (aq) NO3Mg2+
Overall balanced equation: Pb2+(aq) + Mg(s)  Pb(s) + Mg2+(aq) Also fine: Pb(NO3)2(aq) + Mg(s)  Pb(s) + Mg(NO3)2(aq) Pb
# of electrons transferred oxidizing agent reducing agent Spectator ion(s) 2 Pb(NO3)2 Mg NO3– 2. Is hydrochloric acid (HCl(aq)) oxidizing agent? Why or why not? (1 point) Yes, it is because H+ will undergo reduction when forming H2. 3. Complete the table. (3 points) Solution Molar concentration of solution Mass of solute (in g) Volume of Solution (in mL) Molar concentration of sodium ion Na2SO4(aq) 0.205 M 7.28 g 250.00 0.410 M Solute: Na2SO4 Solvent: H2O Work:  142.05 g Na 2SO 4
 0.205 mol Na 2SO 4 
 0.25000 L  


L


 mol Na 2SO 4
 0.205 mol Na 2SO 4

L


  7.28 g Na 2SO 4


  2 mol Na 

  1 mol Na SO   0.410 M Na

2
4 
4. What is the volume (in L) of 25.5 g of hydrogen at STP? (1 point) PV  nRT
V
nRT

P
 mol H 2
 2.02 g H 2
 25.5 g H 2  

L  atm 
 0.08206
  273 K 
mol  K 

 283 L 1 atm