Post on 17-Jan-2016
transcript
Solutions
Percent Concentration
Percent Concentration
Describes the amount of solute dissolved in 100 parts of solution
amount of solute
100 parts solution
Mass-Mass % Concentration
mass/mass % = g solute x 100% 100 g solution
Mixing Solute and Solvent
Solute + Solvent
4.0 g KCl 46.0 g H2O
50.0 g KCl solution
Calculating Mass-Mass %
g of KCl = 4.0 g
g of solvent = 46.0 g
g of solution = 50.0 g
%(m/m) = 4.0 g KCl (solute) x 100 = 8.0% KCl
50.0 g KCl solution
Grams, Moles & %Composition
A solution contains 15 g Na2CO3 and 235 g of
H2O? What is the mass % of the solution?
1) 15% (m/m) Na2CO3
2) 6.4% (m/m) Na2CO3
3) 6.0% (m/m) Na2CO3
Solution
mass solute = 15 g Na2CO3
mass solution = 15 g + 235 g = 250 g
%(m/m) = 15 g Na2CO3 x 100
250 g solution
= 6.0% Na2CO3 solution
Mass-Volume %
mass/volume % = g solute x 100% 100 mL solution
Moles & Volume & %Composition
An IV solution is prepared by
dissolving 25 g glucose
(C6H12O6) in water to make 500.
mL solution. What is the
percent (m/v) of the glucose in
the IV solution?
1) 5.0% 2) 20.% 3) 50.%
Solution
1) 5.0%
%(m/v) = 25 g glucose x 100
500. mL solution
= 5.0 %(m/v) glucose solution
Writing Factors from %
A physiological saline solution is a 0.85% (m/v) NaCl solution.
Two conversion factors can be written for the % value.
0.85 g NaCl and 100 mL NaCl soln
100 mL NaCl soln 0.85 g NaCl
% (m/m) Factors
Write the conversion factors for a 10 %(m/m) NaOH solution
NaOH and NaOH soln
NaOH soln NaOH
% (m/m) Factors
Write the conversion factors for a 10 %(m/m) NaOH solution
NaOH and NaOH soln
NaOH soln NaOH
10 g
10 g100 mL
100 mL
Moles, Volume & %Composition
Write two conversion factors for each of the following solutions:
A. 8 %(m/v) NaOH
B. 12 %(v/v) ethyl alcohol
Solution
Write conversion factors for the following:
A. 8 %(m/v) NaOH
8 g NaOH and 100 mL__100 mL 8 g NaOH
B. 12 %(v/v) ethyl alcohol
12 mL alcohol and 100 mL 100 mL 12 mL alcohol
Using % Factors
How many grams of NaCl are needed to prepare 250 g of a 10.0% (m/m) NaCl solution?
Complete data:____________ g solution
____________% or (______/_100 g_) solution
____________ g solute
Clculation Using % Factors
250 g solution
10.0% or (10.0 g/100 g) solution
? g solute
250 g NaCl soln x 10.0 g NaCl = 25 g NaCl100 g NaCl soln
Calculations using %Compostion
How many grams of NaOH do you need to measure out to prepare 2.0 L of a 12%(m/v) NaOH solution?
1) 24 g NaOH
2) 240 g NaOH
3) 2400 g NaOH
Solution
2.0 L soln x 1000 mL = 2000 mL soln
1 L
12 % (m/v) NaOH = 12 g NaOH
100 mL NaOH soln
2000 mL x 12 g NaOH = 240 g NaOH
100 mL NaOH soln
Moles, Volume & %Composition
How many milliliters of 5 % (m/v) glucose solution are given if a patient receives 150 g of glucose?
1) 30 mL
2) 3000 mL
3) 7500 mL
Solution
5% m/v factor
150 g glucose x 100 mL = 3000 mL
5 g glucose