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.)

Question

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!

Answer 1

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.

Answer 2

To calculate the moles of the second reactant required to react completely with a given amount of the first reactant, you need to use the stoichiometry of the balanced equation. The coefficients in the balanced equation represent the mole ratio between the reactants.

For example, in equation (a):

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

The coefficient of H2SO4 is 1, which tells us that for every 1 mole of BaCl2, we need 1 mole of H2SO4 to react completely. Therefore, if you have 0.147 mol of BaCl2, you would need 0.147 mol of H2SO4.

Similarly, you can apply this method to the other equations:

(b) AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
The coefficient of NaCl is 1, so if you have 0.147 mol of AgNO3, you would need 0.147 mol of NaCl.

(c) Pb(NO3)2(aq) + Na2CO3(aq) → 2NaNO3(aq) + PbCO3(s)
The coefficient of Na2CO3 is 1, so if you have 0.147 mol of Pb(NO3)2, you would need 0.147 mol of Na2CO3.

(d) C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)
The coefficient of O2 is 5, so if you have 0.147 mol of C3H8, you would need 0.147 mol multiplied by the mole ratio, which is 5 mol of O2.

Overall, to calculate the moles of the second reactant, you need to consider the coefficients of the balanced equation and multiply by the given amount of the first reactant.