Investigate (09/10/13)

In your Notebook, prepare a data table like the one on page 121 for all 6 substances. No column for filter exercise!

Work with the students at your table. Follow the instructions on page 120 -121,

start with 3) do not do last bullet.

Write down the items below and tell which is a mixture and which is a

Warm up(09/10/13) Pure Substances vs Mixtures 9-9-2013Look at each picture below, and for each item, be prepared to answerIs it a mixture or a compound? Is it a solution? Is it a suspension? Is it a colloid? Is it homogeneous or heterogeneous?How can we tell the difference? How are mixtures similar or different from compounds?

Matter and Change

Chemistry

Physical ChangesPhysical change: a change in the

physical properties of a substance.

Composition does not change. Phase changes (like liquid to gas)

Evaporation, freezing, condensing, subliming, etc. Tearing or cutting the substance

Chemical Change

A change that produces matter with a different composition than the original matter.

Atoms rearrange themselves into new combinations.

All chemical reactions

Burning of MethaneCH4 +2O2 CO2 + 2H2O

Recognizing a Chemical Change

1. permanent color change2. gas produced (odor or bubbles)3. precipitate (solid) produced 4. light given off 5. heat released (exothermic) or

absorbed (endothermic) examples include

decomposing, rusting, exploding, burning, or and oxidizing.

Quick QuizWhen one substances turns into another, what kind of change has taken place?

A. chemical reaction B. physical reactionC. extensive reactionD. nuclear reaction

Change of Phase

Melting solid liquidCondensation gas liquid

Freezing liquid solid

Evaporation liquid gasSublimation solid gas

Boiling: Evaporation occurring beneath the liquid’s surface.

Temperature vs Time Phase Change Graph

Is changing phase a physical or chemical change?

Pure Substance Matter that has a uniform and

definite composition.

Elements- cannot be broken down chemically into simpler substances

Compounds- all the components are the same (but could be chemically broken down into elements)

Water is a compound. All thecomponents are the same—H2O molecules.

Mixture: a physical blend of two or more substances that are not chemically combined.

Homogeneous-mixture has the same

properties/composition throughout. Homogeneous means the particles are evenly distributed

Heterogeneous-Not uniform composition

Mixtures can be physically separated.

Mixtures exhibit physical properties

similar to the components of the mixture.

Homogenous MixturesSolutions

A solution is a homogeneous mixture formed when one substance dissolves in another.

It is the best mixed of all mixtures.

The substance that is dissolved is the solute and the substance that does the dissolving is the solvent.

Heterogenous Mixtures

Colloids Colloids are mixtures, and look like solutions,

but their particles are too small to settle to the bottom of their container over time.

Colloids can not be filtered out. Colloids obey the Tyndall effect the particles are mixed together but not

dissolved Examples of colloids are mayonnaise, egg

whites, and gelatin.

Heterogenous Mixtures

Tyndall effect

Tyndall effect is occurring if you shine a flashlight through a jar of liquid and see the light beam.

This distinguishes a colloid from a solution.

Heterogenous Mixtures

SuspensionsIn a mixture called a suspension the

particles are very large and will settle out upon standing. Suspensions can be filtered.

Examples include muddy water, sand in water, paint, dust in air, flour in water

Muddy water, will settle when it is left still for a period of time.

Types of mixtures

How can you tell the difference between a solution, a colloid and a suspension?

First, try filtering it, then look for the Tyndall effect.

Mixtures can be physically separated.

Mixtures exhibit physical properties similar to the components of the mixture.

To separate, use differences in the physical properties of the components of the mixture.

Filtration: separates a solid from a liquid in a heterogeneous mixture

Distillation: -separate dissolved solids from a liquid -uses boiling and condensation.

Learning Check

Identify if the following are

1) Homogeneous or 2) Heterogenous

1. 1 perfect, pure air 4. 2 salad dressing

2. 1 ink 5. 1 coffee

3. 1 soft drink 6. 2 Chicken noodle

soup

Learning Check

Circle the solute and underline the solvent

1. 50 g of water and 5 g NaCl

2. 2. 20 g copper and 50 g zinc

3. 30%water and 70% alcohol

4. 18.0 L of nitrogen & 12.0 L of oxygen

Write down the items below and tell which is a mixture and which is a

Warm up Pure Substances vs Mixtures 9-9-2013Look at each picture below, and for each item, be prepared to answerIs it a mixture or a compound? Is it a solution? Is it a suspension? Is it a colloid? Is it homogeneous or heterogeneous?How can we tell the difference? How are mixtures similar or different from compounds?

Today’s Activity

Read Chem Talk on page 122 Draw either a Venn Diagram or table that

compares solutions, suspensions and colloids.

Tomorrow night is OPEN HOUSE !!

Please remind your parents!