Spring 2011. Compound Definition: Two or more different elements chemically bonded by a chemical...

Spring 2011

Compound Definition: Two or more different elements chemically bonded by a chemical reaction to form a new substance.

Examples: NaCl, H2O, CO2

How can they be broken down or separated?: Compounds can only be broken down or separated by chemical means. (it requires a chemical reaction to break them apart).

Mixtures Definition: a combination of two or more substances that are not chemically combined.

Examples: salad, kool-aid, blood, salt water

How can they be broken down or separated?: Mixtures can be broken down physically. No chemical reaction is required.

Characteristics of Mixtures

A.No chemical change occurs(the substances keep their identity).

B.THE SUBSTANCES CAN BE SEPARATED!!!!!

Atoms vs. Elements vs. Compounds vs. Mixtures

MIXTURES COMPOUNDS

Components are elements, compounds or both

Components are elements

Components keep their original properties

Components lose their original properties

Separated by physical means

Separated by chemical means

Formed using any ratio of components

(Ex- salad, if you want more lettuce, just add it)

Formed using a specific ratio of elements

(Ex- water H2O… not H2O2)

Types of Mixtures

A.Heterogeneous- the different substances are visible in the mixture.

B.Homogeneous – The mixture looks the same and has the same characteristics throughout.

Types of Heterogeneous mixtures

a. Suspension: mixtures in which particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out.

Solution: A mixture that looks to be the same but is composed of 2 or more substances appears to be a single substance.

Examples: Alloys, soda, salt water, tea.

Colloid: a mixtures in which the particles are dispersed (spread) throughout but are not heavy

enough to settle out. Examples: Milk, mayonnaise, stick deodorant, shaving cream, and jello are all colloids.

Colloids are like a mix between solutions and suspensions

Parts of a Solution

• Solute: is the substance that is dissolved.• Ex. Salt, sugar.

• Solvent: is the substance in which the solute is dissolved in.• Does the dissolvingEx. Water.

Solubility=the ability of an object to dissolve into other substances.Solubility of Solids and Temperature Change:Solubility of solids increases as temperature increases.

Solubility of Gases and Temperature Change:Solubility of gases decreases as temperature increases.

Suppose you had a mixture of iron nails, salt and water…

How would you separate this mixture completely?

Based on which physical properties would you base your method on?

Ways Mixtures Can Be SeparatedFiltration – Used to separate heterogeneous mixtures composed of liquids and solids

Using some form of filter to separate particles that won’t dissolve from a liquid.

This is good for separating an insoluble solid from a liquid (an insoluble substance does not dissolve in water).

EX: sand can be separated from a mixture of sand and waterUsing filtration

Evaporation – Used when you wish to collect a solute from a solution.

Evaporate a LIQUID to leave the SOLID behind.

Separating Mixtures Continued

Distillation: the process that separate a mixture based on the boiling points of the components.

Used to separateHomogeneous mixtures

Chromatography – used to separate out mixtures of dyes.

Shows all the colors used to make certain dyes or pigments

ink stain

Get a piece of paper and fold “hamburger style”.

Fold “hamburger style” again.Cut the TOP half of the paper up to the

“mountain”.Label one side “ACID” and the other side

“BASE”.The inside of the flaps should contain your

notes on acids, bases, and the pH scale. Follow along with PowerPoint.

To determine the difference between Acids & Bases

Discuss the importance of studying Acids & Bases

Perform an experiment dealing with Acids & Bases

Acids can be characterized by:1. A sour taste. Try drinking lemon juice (citric

acid)2. It turns litmus paper red3. Have a pH from 0-7, the lower the pH

number the stronger the acid…4. They can neutralize (chemical reaction) a

base.5. They are corrosive (eat through things).

A Base is characterized by:

1. A bitter taste. (TUMS)2. It feels slippery. (Soapy Water)3. It turns Red Litmus Blue.

4. Have a pH from 7-14, the higher the pH number, the stronger the base.

5. Can neutralize (chemical reaction) an acid.

The pH scale measures how

acidic or basic a mixture is.

Draw a pH scale in your foldable. You do NOT have to draw the pictures, but you should include some examples of acids and bases on your scale.

Acids have a ph from 0-7Lower pH value indicates a stronger acid.

Bases have a pH from 7-14Higher pH value indicates a stronger base.

What happens when the pH of a substance is 7?

Ans: A pH level of 7 indicates a Neutral Substance i.e: Water!

Neutral- is neither an acid nor a base.Neutralization- chemical reaction between an

acid and a base to form a neutral substance (salts).

What do you think is the pH level of NYC tap water?

The pH of a swimming pool must be checked periodically. Why?

Is it important for Lakes & Rivers to maintain a certain pH?

Test the pH of Pepsi, tap water, and drain cleanerOn the back of your foldable copy the chart below

to record your observations about acids and bases.

GOOD LUCK!!!

Substance Color (after dipping)

pH Acid/Base/Neutral

Pepsi

Water

Drain Cleaner

1. The smallest part of matter is:a. Cellb. Particle c. Moleculed. Atom

2. To find information about elements:a. Look at a dictionaryb. Use a periodic tablec. Google themd. Look under a microscope

3. Vocabulary words are:a. Any word you don’t knowb. Words that may help me understand a concept betterc. Important to all subject areas.d. All of the above.

1. A mixture where you can see the individual parts is called a:

a. Homogenous mixture

b. Solution

c. Colloid

d. Heterogeneous mixture 2. A mixture where you cannot see the individual parts is

called a:

a. Homogenous mixture

b. Suspension

c. Heterogeneous mixture

d. Compound 3. The main difference between compounds and mixtures is:

a. Compounds can be separated but mixtures cannot.b. Compounds do not require a chemical reaction to occur.c. Mixtures can be separated by physical means.d. Mixtures require a chemical reaction.

1. A solute is:a. The liquid that a solid or gas is dissolved into.b. The solid or gas that is dissolved.c. Is greater than the solvent.2. A solvent is:

a. The liquid that a solid or gas is dissolved into.b. The solid or gas that dissolved.c. Is less than the solute.

3. A solution is:a. A homogenous mixtureb. A mixture with a solute and solventc. Both A and B

1. When you balance chemical equations:a. The atoms are equal on both sides of the equation.b. There are more atoms on the reactant side of the equation.c. There are more atoms on the product side of the equation.

2.Solubility of solids: a. Increases with a decrease in temperature.

b. Increases with an increase in temperature.c. Decreases with an increase in temperature.

3.The two main types of mixtures are:a. Heterogeneous and homogenousb. Solutions and suspensionsc. Solute and solvent