Balance and complete each of the following, and indicate how many moles of the second reactant would be required to react completely with 0.147 mol of the first reactant. (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer.)

(a) BaCl2(aq) + H2SO4(aq)
BaCl2(aq)+H2SO4(aq) → BaSO4(s)+2HCl(aq
H2SO4 mol?

(b) AgNO3(aq) + NaCl(aq)
AgNO3(aq)+NaCl(aq) → AgCl(s)+NaNO3(aq)
Correct.
NaCl mol?

(c) Pb(NO3)2(aq) + Na2CO3(aq)
Pb(NO3)2(aq)+Na2CO3(aq) → 2NaNO3(aq)+PbCO3(s)
Correct.
Na2CO3 mol?

(d) C3H8(g) + O2(g)
C3H8(g)+5O2(g) → 3CO2(g)+4H2O(l)
Correct.
O2 mol?

I got the balanaced equations correct, I am just unsure of how to calculate the moles for each. Thanks!

1 answer

You've done the hard part. Look at the coefficients. The first equation (a) tells you that 1 mol BaCl2 reacts with 1 mol H2SO4 so wouldn't you guess that 0.147 mol BaCl2 will require 0.147 mols H2SO4?

(d) 1 mol C3H8 requires 5 mols O2; therefore, 0.147 mols C3H8 will require 0.147 x 5 = ? mols O2.