# Solutions in Chemical Reactions

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Solutions in Chemical Reactions
Chapter Solutions 12.6 Solutions in Chemical Reactions Copyright © by Pearson Education, Inc. Publishing as Benjamin Cummings

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. volume (L) x molarity ( mol ) = moles 1 L If molarity (mol/L) and moles are given, the volume (L) can be determined mol x L = volume (L) mol

Using Molarity of Reactants
How many mL of 3.00 M HCl are needed to react 4.85 g CaCO3? 2HCl(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 mol CaCO mol HCl mL HCl

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

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

Solution 3) 27.8 mL 0.0185 L x 0.225 mol NiCl2 x 1 mol Na2S x 1000 mL
1 L mol NiCl mol = mL Na2S solution

Learning Check What is the molarity if 15.0 mL of AgNO3 solution
reacts with 22.8 mL of M MgCl2? MgCl2(aq) + 2AgNO3(aq) AgCl(s) + Mg(NO3)2(aq) 1) M 2) M 3) M

Solution 3) M AgNO3 L x mol MgCl2 x 2 mol AgNO3 x = 1 L mol MgCl L = mol/L = M AgNO3

Learning Check How many liters of H2 gas at STP are produced
when 12.5 g Zn react with 20.0 mL of 1.50 M HCl? Zn(s) + 2HCl(aq) ZnCl2 (aq) + H2(g) 1) L H2 2) L H2 3) L H2

Solution 2) 0.336 L H2 Limiting Reactant
12.5 g Zn x 1.00 mol Zn x 1 mol H2 x 22.4 L = L H2 65.41 g Zn 1 mol Zn 1 mol L x 1.50 mol HCl x 1 mol H2 x L 1 L mol HCl 1 mol = L H2 gas

Summary of Chemical Reactions