1. Solutions in Chemical Reactions
Chapter 7 Solutions
7.6
Solutions in Chemical Reactions
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

2. Molarity in Chemical Reactions
In a chemical reaction,
the volume and molarity of a solution are used to determine the moles of a reactant or product.
molarity ( mole ) x volume (L) = moles
1 L
if molarity (mole/L) and moles are given, the volume (L) can be determined
moles x L = volume (L)
moles

3. Using Molarity of Reactants
How many mL of 3.00 M HCl are needed to completely
react with 4.85 g CaCO3?
2 HCl(aq) + CaCO3(s) CaCl2(aq) + CO2(g) + H2O(l)
STEP 1 Given M HCl; 4.85 g CaCO3
Need volume in mL
STEP 2 Plan
g CaCO mole CaCO mole HCl mL HCl

4. Using Molarity of Reactants (cont.)
2 HCl(aq) + CaCO3(s) CaCl2(aq) + CO2(g) + H2O(l)
STEP 3 Equalitites
1 mole CaCO3 = g; 1 mole CaCO3 = 2 mole HCl
1000 mL HCl = 3.00 mole HCl
STEP 4 Set Up
4.85 g CaCO3 x 1 mole CaCO3 x 2 mole HCl x 1000 mL HCl
100.1 g CaCO mole CaCO mole HCl
= mL HCl required

5. Learning Check How many mL of a 0.150 M Na2S solution are needed to
completely react 18.5 mL of M NiCl2 solution?
NiCl2(aq) + Na2S(aq) NiS(s) + 2 NaCl(aq)
1) mL
2) mL
3) mL

6. Solution
3) 27.8 mL
L x mole NiCl2 x 1 mole Na2S x 1000 mL
1 L mole NiCl mole
= mL Na2S solution

7. Learning Check If 22.8 mL of 0.100 M MgCl2 is needed to completely
react 15.0 mL of AgNO3 solution, what is the molarity of
the AgNO3 solution?
MgCl2(aq) + 2 AgNO3(aq) AgCl(s) + Mg(NO3)2(aq)
1) M
2) M
3) M

8. Solution
3) M AgNO3
L x mole MgCl2 x 2 mole AgNO3 x P
1 L mole MgCl L
= mole/L = M AgNO3

9. Learning Check How many liters of H2 gas at STP are produced
when Zn react with 125 mL of 6.00 M HCl?
Zn(s) + 2 HCl(aq) ZnCl2 (aq) + H2(g)
1) L H2
2) L H2
3) L H2

10. Solution 2) 8.40 L H2 gas 0.125 L x 6.00 mole HCl x 1 mole H2 x 22.4 L
1 L mole HCl 1 mole
= L H2 gas
2) 8.40 L H2 gas
0.125 L x 6.00 mole HCl