Solutions, Acids & Bases

The Water MoleculeHow many protons does a water molecule

have? How many electrons?What is the overall charge of a water

molecule?8

OOxygen15.9999

1

HHydrogen

1.0079

The Water MoleculeHow many protons does a water molecule have?

10How many electrons? What is the overall charge of a water molecule?

8

OOxygen15.9999

1

HHydrogen

1.0079

The Water MoleculeHow many protons does a water molecule have? 10

How many electrons? 10What is the overall charge of a water molecule?

8

OOxygen15.9999

1

HHydrogen

1.0079

The Water MoleculeHow many protons does a water molecule have? 10

How many electrons? 10What is the overall charge of a water molecule?

0 + 10 – 10 = 0

8

OOxygen15.9999

1

HHydrogen

1.0079

PolarityDraw a water molecule

e-

e-

e-

e-

e-

e-

e-e-

e-

e-

PolarityOxygen has _____ protons, while Hydrogen only

has _____ proton. Oxygen’s greater attraction for electrons causes the Oxygen to have a slightly ______________ charge, while Hydrogen maintains a slightly _____________ charge.

8

OOxygen15.9999

1

HHydrogen

1.0079

PolarityOxygen has _____ protons, while Hydrogen only

has _____ proton. Oxygen’s greater attraction for electrons causes the Oxygen to have a slightly ______________ charge, while Hydrogen maintains a slightly _____________ charge.

8

OOxygen15.9999

1

HHydrogen

1.0079

8 1

negativepositive

PolarityKey: Why is a water molecule polar?

There is an uneven charge

between the

positive hydrogen

and negative oxygen.

PolarityDraw Hydrogen bonds between one water

molecule and another.

Hydrogen BondsIn terms of a water

molecule explain what a hydrogen bond is:

The attraction of the positively charged hydrogen atom of one water molecule to the negatively charged oxygen of another water molecule.

Hydrogen BondsCohesion:

The ability for water molecules to stick to themselves.

Hydrogen BondsHow does cohesion explain why some insects

can walk on water?

Hydrogen BondsAdhesion:

The ability for water molecules to stick to other materials.

Hydrogen BondsHow does adhesion change the way you read

this graduated cylinder? Why?

Hydrogen BondsWhat is capillary action in plants? Water clings to the inside of plant roots and climbs, just like water will climb up a paper towel if you put half of it in water.

Solutions and SuspensionsMixture: A combination of two or more

substances that are physically mixed, not chemically combined. Example: Soil, salsa, trail mix, milk, cereal,

sugar water

Solutions and SuspensionsSolutions: A mixture formed when one

substance dissolves in another EVENLY.Example: Salt water

Solutions and SuspensionsSolutions: A mixture formed when one

substance dissolves in another EVENLY.Example: Salt water

A. Solute: Substance dissolved in a solution

Salt = Solute

Solutions and SuspensionsSolutions: A mixture formed when one

substance dissolves in another EVENLY.Example: Salt water

A. Solute: Substance dissolved in a solution B. Solvent: Substance that does the dissolving

Salt = SoluteWater = Solvent

Solutions and SuspensionsSuspensions: A mixture of water and non-

dissolved materials.Example: Blood, aerosol sprays, milk

Apply What You KnowSolution or Suspension? Salt and WaterSand and WaterMilkKool-AidChicken Noodle Soup

Acids, Bases, and pHA. The ______ scale is used to measure the

strength of acids and bases.B. Complete the table:

pH Examples

Characteristics

Acids

Neutral

Bases

pH

1-7

Lemon, vinegar, soda, aspirin

Sour, burns, dissolves things

7 Pure Water Not acidic, not basic!

7-14

Soap, baking soda, ammonia

Bitter, slippery

H+

OH-

H2O

Acids, Bases, and pHC. Buffer: Weak acids or bases that neutralize strong acids or bases.Why are buffers important? When acids and bases are added to the body, the blood “buffers” preventing a pH change.

Buffers in the Body

pH of blood MUST be between 7.35 and 7.45

Removing CO2 from the blood helps increase the pH

Removing HCO3- from the blood helps lower the pH

Buffers (Bicarbonate) maintain this acid-base balance in the blood.

pH Lab

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5 6 7 8

Each lab station is doing 2 experiments! (3 people per tray)

Check assignment on back wall

pH Lab

Overview4 drops of each samplePut on white scratch paperDip a small strip of pH paper in each sampleCompare the color to the chart Add 4 drops cabbage juiceColor the box & recordAnswer questions

1 2 3 4

5 6 7 8

General Lab RulesStay at your lab table unless you are the

designated person to get supplies.Read ALL DIRECTIONS CAREFULLY!!!!Wash your trays with hot, soapy water.Clean your lab station & push in stools.Your lab should look cleaner than when you

started!Have fun!