Download - BELLRINGER Compare and explain in complete sentences what is a saturated solution.

BELLRINGER

Compare and explain in complete

sentences what is

a saturated solution.

Previous homework

Finish and submit 4 BRs for the previous week.

SOLUTIONSIII

Water and Solutions

Concentration and Solubility

4 9.2 Concentration and Solubility

Suppose you dissolve 10.0 g of sugar in 90.0 g of water. What is the mass percent concentration of sugar in the solution?

Asked: The mass percent concentration

Given: 10 g of solute (sugar) and 90 g of solvent (water)

Relationships: 100%mass of solute

concentrationtotal mass of solution


Suppose you dissolve 10.0 g of sugar in 90.0 g of water. What is the mass percent concentration of sugar in the solution?

Asked: The mass percent concentration

Given: 10 g of solute (sugar) and 90 g of solvent (water)

Relationships:

Solve:

100%mass of solute

concentrationtotal mass of solution

10

100%10 90

10%g sugar

concentrationg of solution

sugar


( )( )

( )

( )( / )

( )

( )(%) 100

( )

,

mass of solute gconcentration g L

volume of solution L

mass of solute gconcentration

m

mol

ass of solution

es of solute mmol

oleconcentration

volume of solarity M

n

g

utio L

Concentration

There are several ways to express concentration


Concentration

Calculate the molarity of a salt solution made by adding 6.0 g of NaCl to 100 mL of distilled water.



Concentration

Asked: Molarity of solution

Given: Volume of solution = 100.0 mL, mass of solute (NaCl) = 6.0 g

Relationships:

22.99 35.45 58.44 /

1,000 1.0 , 100 0.10

molesM

L

Formula mass of NaCl g mole

mL L therefore mL L



Concentration



Relationships:

Solve:

22.99 35.45 58.44 /

1,000 1.0 , 100 0.10

molesM

L


mL L therefore mL L

0.

0.1031.03

16.0

58.

0.100

344

10mole NaCl

moles NaCl g NaClg NaC

mole

moles Na

s

Cl

M

l

ML



Concentration



Relationships:

Solve:

Answer: 1.03 M solution of NaCl

22.99 35.45 58.44 /

1,000 1.0 , 100 0.10

molesM

L


mL L therefore mL L

16.0 0.103

58.4

0.

4

103

0.101 03

0.

mole NaClmoles NaCl g NaCl moles NaCl

g NaCl

Mmoles

ML


sugar

100 mLH2O

10 g

What happens when you add 10 g of sugar to 100 mL of water?

Conc. (%) = 10 g/110 g

Solubility


100 mLH2O


Conc. (%) = 10 g/110 g

Water molecules dissolve sugar molecules

sugar10 g

Solubility



But when two sugar molecules find each other, they will become “undissolved” (solid) again…

Solubility



But when two sugar molecules find each other, they will become “undissolved” (solid) again…

… then, they become redissolved in water again.

Solubility



This is an aqueous equilibrium!

Equilibrium

Solubility


Solubility

low

high

Co

nce

ntr

atio

n

Equilibrium

dissolving “undissolving”

10 g sugar

100 mLH2O Conc. (%) = 10 g/110 g

20oC


Solubility

low

high

Co

nce

ntr

atio

n

Equilibrium



saturation: situation that occurs when the amount of dissolved solute in a solution gets high enough that the rate of “undissolving” matches the rate of dissolving.

Equilibrium



saturation: situation that occurs when the amount of dissolved solute in a solution gets high enough that the rate of “undissolving” matches the rate of dissolving.

204 g sugar

100 mLH2O Conc. = 204 g/100 mL

20oC

Solubility


Solubility

low

high

Co

nce

ntr

atio

n

Equilibrium


250 g sugar

100 mLH2O

Conc. = 250 g/100 mL

20oC

Undissolved sugar


210 gsugar

100 mLH2O

20oC

Undissolved sugar

Temperature and solubility

210 gsugar

100 mLH2O

30oC

All the sugar is dissolved


Temperature has an effect on solubility

Temperature and solubility

210 gsugar

100 mLH2O

20oC

Undissolved sugar

210 gsugar

100 mLH2O

30oC

All the sugar is dissolved


ACTIVITY

READ THE TEXTBOOK FROM PAGE 239.

WORK PROBLEMS FROM PAGES 244 and 245.


Homework

FINISH YOUR ACTIVITY ASSIGNMENT AND SUBMIT IT

TOMORROW.