Question

Part A) When iron and hydrochloric acid are mixed, iron(II) chloride and hydrogen gas is produced. How many grams of iron are needed to produce 31.0 L of gas at 23.0^oC and 750 mm Hg?

Part B) Balance the following using the ½ reaction method

solid aluminum plus   zinc (II) ion  

Answer 1

a)

Fe + 2HCl --> FeCl2 + H2

V = 31 L

T = 23 or 296

P = 750 mm Hg or 750/760 = 0.9868 atm

PV = nRT

n = PV/(RT) = 0.9868 *31 / (0.082*296) = 1.26 mol of H2

since

Fe + 2HCl --> FeCl2 + H2

then, ratio is 1:1

w eneed 1.26 mol of Fe

B)

Al + Zn+2

Al3+ + 3 e− <---> Al(s) −1.662

Zn2+ + 2 e− <---> Zn(s) −0.7618

The most negative will be oxidized, then

Zn2+ + 2 e− <---> Zn(s) −0.7618

Al(s) <--->Al3+ + 3 e−   +1.662

Balance charges

3Zn2+ + 6 e− <---> 3Zn(s) −0.7618

2Al(s) <--->2Al3+ + 6 e−   +1.662

Add both:

3Zn2+ + 6 e− + 2Al(s)  <---> 3Zn(s) + 2Al3+ + 6 e−

cancel electrons

3Zn2+ + 2Al(s)  <---> 3Zn(s) + 2Al3+