Solutions and pH. Solutions Mixtures – a combination of substances that retain their original...

Solutions and pH

Solutions Mixtures – a combination of substances

that retain their original properties

Ex. trail mix, air, salt water

SolutionsSolution – mixture of one or more substances

uniformly distributed in another substance.

Can be solid, liquid, gas

ex. Plasma (liquid)

brass (solid) copper and zinc

soda (liquid/gas) water and CO2

Solutions2 parts:

1. Solute – substance being dissolved2. Solvent- substance doing dissolving

Salt water: salt = solute water = solvent

Aqueous solutions- water is the solvent due to hydrogen bonding

Water = universal solvent because it can dissolve most things

Concentration

Concentration- amount of solute dissolved in a fixed amount of solution

When no more solute can be dissolved….solution is SATURATED

Salt will no longer dissolve

Acids & BasesThe Homeostasis of living things depends

on the degree of acidity (acid) and alkalinity (base) in certain areas

Water Acids and bases are solutions made by the dissociation of

water Water naturally breaks down into ions of opposite charges,

this is called dissociation. Water will form these ions naturally (H3O+ & OH-) and in EQUAL amounts.

H2O H+ + OH-

This is why water is NEUTRAL!

Hydronium (H3O+) ions = hydroxide (OH- ) ions

Acids & Bases

Acidity= measure of the amount of hydronium (H3O+) ions dissolved in a solution.

Alkalinity (AKA basic solution)= measure of the amount of hydroxide (OH- ) ions dissolves in a solution

Acids

- more H+ ions released- pH < 7- Sour taste- Corrosive on metals- Burns skin

• Ex. Orange juice, • vinegar, sulfuric acid

*Homeostasis relevance- your stomach must have a

certain acidity to function properly

Bases

-more OH- ions released- pH > 7- Tastes bitter- Slippery- Irritate the skin

- Ex. NaOH- Homeostasis relevance- your

small intestine needs a certain alkalinity (basic) to function properly

pH Scale

- Used to measure the amounts of H3O+ and OH- ions in a solution

- Tells you how acidic or basic something is

- Ranges 0-14, 7 = neutral above 7 = base below 7 = acid

- Ten fold system- Measure pH with litmus

paper

BuffersBuffers- chemical substances that neutralize

small amounts of acids and bases

Ex. Acids { stomach acid & urine

Ex. Bases { blood & intestinal fluid

- If not at the proper pH level, these body systems will not function properly and…

you’ll need to use a Buffer ex. Alka seltzer