MIXTURES & COMPOUNDS

By Aimee Chavez

Matter

Heterogeneous mixture

Homogenous Mixture

solutionPure substance

compoundElement

Uniform Distribution?

YESNO

Fixed Composition ?

Yes No

Can it be broken down into simpler

substances?

Pure Substances

Has a fixed, uniform composition and properties

Can be an element or a compound.

Atoms & Elements Elements: A substance that cannot be broken down into

simple substances. An atom is the smallest particle of an element. An element has a fixed composition because it contains only one type of atom.

Atoms: basic building block of matter. Unique physical and chemical properties determined by the number or protons.

Examples are nitrogen and oxygen the two main gases you breathe.

Compounds Made from two or more simpler substances. Can be broken down to simpler substances

by chemical reactions (burning, reacting with chemicals, reacting with light)

Properties differ from those substances that make them. Example O and H are gases at room temperature, but water is a liquid.

Contains 2 or more elements joined in a fixed proportion /ratio.

H₂O water CO₂ carbon dioxide Na Cl sodium chloride

Mixtures Retain some of the properties of their

individual substances. Properties of a mixture can vary because

the composition of a mixture is not fixed. The type of pepper and quantity used determines hotness.

May or may not be evenly distributed : homogenous and heterogeneous

Homogenous

The substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another.

Based on the size of its largest particles, a mixture can be classified as a solution, a suspension, or a colloid.

Heterogeneous Means different and kind Particles are noticeably different from one

another.

Suspension

A heterogeneous mixture that separates into layers over time. (pepper and water)

Particles are not evenly mixed and can be easily separated by settling or filtration

Can’t scatter light. Muddy water

Colloids

Contains particles that are intermediate in size between the small particles in solution and the larger particles in a suspension

Doesn’t separate into layers and can’t use filter paper to separate particles

Can scatter light Examples: milk, fog (water droplets in air),gelatin,

mayonnaise, shaving cream, whipped cream

Solutions

When substances dissolve and forms a homogenous mixture, the mixture that forms is called a solution. (salt + water)

The particles are too small to settle out of the solution, be trapped by a filter, or scatter light.

Can separate by boiling and evaporating

Parts of a solution

Solvent: Largest amount, dissolves other substance

Solute: Smaller amount, is dissolved

Water is a “universal solvent” and is part of many solutions. In many living organisms nutrients are dissolved in water. It is an important part of blood, saliva, tears. For trees water is a part of sap which carries sugar to the cells.

Common Solutions

Solute Solvent Solution

O Oxygen (g) Nitrogen (g) Air (g)

carbon dioxide (g) Water (l) Soda (l)

sodium chloride (s) Water (l) Sea Water (l)

Zinc (s) Copper (s) Brass (s)

Iron (s) Carbon (s) Steel (s)

Acetic Acid (l) water (l) Vinegar (l)

Silver (s) Mercury (l) Dental Fillings (s)

Solubility Solubility: a measure of how well a

solute can dissolve in a solvent at a given temperature. Can be used as a property

Saturated: no more sugar dissolves into tea, as much solute as possible is dissolved in a given temperature

Unsaturated: doesn’t hold as much of a solute as is possible at a given temperature

Changing Solubility

1. Temperature: Most substances in crease when temperature is increased except gases

2. Pressure: Gases become more soluble with increased pressure

3. Like dissolves like: polar and non polar don’t mix

Concentration

Concentration : the amount of solute dissolved in a solvent.

Dilute: Little solute Concentrated : more solute

Effects of solutes

1. solutes can decrease the F.P. of solvent 2. solutes can increase the B.P. of solvent

Car antifreeze: acts to decrease the F.P to – 13 C and Increase B.P. to 176 C

Adding salt to water increases the boiling point.

Adding salt to ice decreases the freezing point

Solids from Solutions

Crystallization: Solute comes back out of solution to form a solid by cooling or evaporating.

Some are chemical reactions and form a precipitate. In a shower or sink minerals interact with the water and soap leaving soap scum.

In caves water can interact with limestone to form stalactites and stalagmites.

Acids

Sour taste Common examples: lemons, limes,

citrus, vinegar, tea, tomatoes, green leafy vegetables ( folic acid), fertilizer ( nitric acid and phosphoric acid), car battery ( sulfuric acid), lactic acid from exercise

Reacts with metals (Mg, Zn, and Fe) and is corrosive and carbonates (forms a gas) limestone

Turns Blue litmus paper Red

Acids & Bases in Digestion

Mouth PH is 7 contains amylase which breaks down carbohydrates to simple sugars

Stomach contains HCL which has a PH of 2 the enzyme pepsin breaks down proteins to amino acids and works best with acids

Small Intestine contains Bicarbonate ion which is basic and has a PH of 8 , other enzymes break down Carbohydrates, fates, and proteins which works best in a basic environment.

Bases

Bitter taste Slippery Common examples: drain cleaners, glass

cleaners, ammonia, MOM, calcium carbonate, baking soda, soap, shampoo, detergent

Turns red litmus paper Blue

PH Scale

Tells if the substance is an acid or base 0-14 Low PH = High Hydrogen ions Acidic High PH = Low Hydrogen ions Basic Limes = 1.8 Bananas = 4.5 Milk = 6.3 Eggs = 7.1

Acid Rain

It is normal to have some acid in rain and a PH about 5.5. Some places the acid rain can have a PH as low as 3.0. The acid is from Nitrogen oxide and Sulfur Oxide. This acidic rain can damage statues, buildings, forests and kill fish

Acid & Base Reaction

Neutralization can occur with the correct concentration of acid and base. It forms salts and water.