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Transcript of Are you ready for your quiz tomorrow? Take out a scratch sheet of paper, a pencil/pen, and a...
Are you ready for your quiz tomorrow?• Take out a scratch sheet of paper, a
pencil/pen, and a calculator
1. A gas at 3 atmospheres has a solubility of 17 g/L. If we changed the pressure to 20 atmospheres, what is the gas’s solubility?
2. We have a 30% solution of sodium chloride. We made this solution by adding 57 grams of salt to how many grams of water?
3. What is the concentration of a solution made from 170 grams of BaCl2 and 300 grams of water?
4. We have 256 grams of a 30% sodium chloride solution. How many grams of salt and how many grams of water were used to make the solution?
5. Don’t forget about your solubility curves!! You’ll see these types of problems tomorrow.
1. A gas at 3 atmospheres has a solubility of 17 g/L. If we changed the pressure to 20 atmospheres, what is the gas’s solubility?
2
2
1
1
P
S
P
S
203
17 x
3x = 340
x = 113 g/L
2. We have a 30% solution of sodium chloride. We made this solution by adding 57 grams of salt to how many grams of water?
%100solution
solute
3010057
x
solventsolutesolution
solutionofgx
190
waterg
water
133
57190
3. What is the concentration of a solution made from 170 grams of BaCl2 and 300 grams of water?
%100solution
solute
100)300170(
170
%100 sovlentsolute
solute
%2.36100470
170
4. We have 256 grams of a 30% sodium chloride solution. How many grams of salt and how many grams of water were used to make the solution?
%100solution
solute
30100256
x
solventsolutesolution
saltsoluteofgx
)(9.76
waterg
water
1.179
9.76256
• Sometimes the terms diluted and concentrated are not specific enough
• Just like in a cooking recipe, in chemistry lab you may need a certain amount to make your experiment work properly
Molarity (M)
• Molarity, M, molar concentration• 2 M = pronounced as 2 molar• Molarity is another way to express concentration as
moles per liter
• This means you need to remember your flow chart so that you can convert from grams to moles if grams is given in the problem!
solutionofLiters
soluteofmolesMolarity
Remember if we’re given grams to get to moles we do
Molar Mass Grams / mole
x
Particles (atoms or
molecules)Moles
Avogadro’s Number
6.02 x 1023 particles/mole
÷
x
Mass (grams)
÷
massmolar
grams
• We can manipulate the molarity equation…
solutionofLiters
solutemolesMolarity
massmolar
gramsmoles
solutionofLiters
massmolargrams
Molarity
What is the molarity of a solution containing 58 grams of sodium chloride in 1 liter of water?
solutionofLiters
massmolargrams
Molarity
1)5.3523(
58Molarity
M1
Calculate the molarity of 100 mL solution containing 50 grams of H2SO4.
• Don’t forget that we must use Liters! • Remember King Henry Died Unexpectantly Drinking Chocolate
Milk– KHDUDCM• 100 mL = 0.1 L
solutionofLiters
massmolargrams
Molarity
1.0)1641.322(
50Molarity M1.5
1.01.98
50
Molarity
How many grams of salt would be dissolved in 1 L of a 0.5 M solution of NaCl
solutionofLiters
soluteofmolesMolarity
15.0
x
NaClofmolesx 5.0
NaClg25.29)5.3523(5.0