entry task: april 27 th friday question: what is the molarity of 1.2 moles of calcium carbonate in...
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Entry Task: April 27th Friday
Question:
What is the molarity of 1.2 moles of calcium carbonate in 1.22 liters of water?
Agenda:
Sign off Discuss Concentration wsNotes on DilutionsHW: Concentration and Dilution ws
1. What is the percent concentration of 75.0 g of ethanol dissolved in 500.0 g of water?
= % NaHCO3
75.0 g ethanol500g water + 75 g ethanol
500g water + 75 g ethanol= 575 g solution
X 10075g NaHCO3
575 g solution= 13.0% ethanol
solution
2. What is the percent concentration of benzene in a solution containing 14.2 grams of benzene in 28.0 grams of carbon tetrachloride?
= % solution14.2 g benzene
28.0 g CCl4+ 14.2 g benzene
28.0 g CCl4+ 14.2 g benzene = 42.2 g solution
X 10014.2g benzene
42.2 g solution= 33.6% solution
3. You have 1500.0 grams of bleach solution. The percent by mass of the solute sodium hypochlorite, NaOCl, is 3.62%. How many grams of NaOCl are in the solution?
= 3.62% NaOClXg NaOCl
1500 g solution
= 3.62 100
Xg NaHCO3
1500 g solution
= 54.3g NaOCl
1500 X 3.2 = 5430 g100
4. What is the percent by volume of ethanol in a solution that contains 35 ml of ethanol in 115 ml of water?
= X% by volume ethanol solution
35 ml of ethanol
35 ml ethanol + 115 ml of water
35 ml ethanol
150 ml solution
= 23.3 %
X 100
5. What is the percent by volume of methanol in a solution that contains 25 ml of methanol in 75 ml of water?
= X% solution25 ml of methanol
25 ml ethanol + 75 ml of water
25 ml ethanol
100 ml solution
= 25.0 %
X 100
6. What is the molarity of an aqueous solution containing 40.0g of glucose (C6H12O6) in 1.5L of solution?
40 g of C6H12O6
180.16 g C6H12O6
1 mole of C6H12O6
0.222 moles of C6H12O6
1.5 L solution
= 0.148 M
7. What is the molarity of a bleach solution containing 9.5 g of NaOCl per liter of bleach?
9.5 g of NaOCl
74.44 g NaOCl
1 mole of NaOCl
0.128 moles of NaOCl 1.0 L solution
= 0.128 M
8. Calculate the molarity of 1.60 L of a solution containing 1.55 g of dissolved KBr.
1.55 g of KBr
119.0 g KBr
1 mole of KBr
0.013 moles of KBr
1.60 L solution
= 0.00814 M
9. Calculate the number of moles of a 125 ml solution (convert to liters) 0.0500M Ba(OH)2.
X moles of Ba(OH)2
0.125 L solution= 0.0500 M
(0.125 L)(0.0500) = 0.00625 moles
10. Calculate the number of grams of a 350 ml solution (convert to liters) 1.50 M Ba(OH)2.
0.525 mol of Ba(OH)2 171.3 g Ba(OH)2
1 mole of Ba(OH)2
X moles of Ba(OH)2
0.350 L solution= 1.50 M
(0.350 L)(1.5) = 0.525 moles Ba(OH)2
89.9 g Ba(OH)2
Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.
Dilution
Add Solvent
Moles of solutebefore dilution (i)
Moles of soluteafter dilution (f)=
MiVi MfVf=
Dilutions: M1V1 = M2V2
Molarity and Volume of the original solution = Molarity and Volume of the diluted solution.
Make sure the volumes match!!!
Dilutions: M1V1 = M2V2
P1. What volume, in milliliters of 2.00M calcium chloride (CaCl2) stock solution would you use to make 0.50 L of 0.300 M calcium chloride solution? Convert liters to milliliters.
(2.00 M)( X) = (0.300 M )(500 ml)
150 2.00M
= 75 ml
Dilutions: M1V1 = M2V2
P2. What volume of a 3.00M KI solution would you use to make 0.300 L of a 1.25 M KI solution?
(3.00 M)( X) = (1.25 M )(0.300L)
0.375 3.00M
= 0.125 L or 125 ml
Dilutions: M1V1 = M2V2
P3. If I add 25 ml of water to 125 ml of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?
(0.15 M)( 125 ml) = (X M )(150 ml)
18.75 150 ml
= 0.125 M
Use the rest of the period to work on
homework