CHEMISTRY

Unit 02, Lesson 02

Classification of Matter

Fractional Distillation

Images source: http://en.wikipedia.org/wiki/Fractional_distillation

Separation Stations

Graphic Organizer Construction

• Construct a 3 tab graphic organizer “Elements, Compounds, and Mixtures”– Materials:

• 1 sheet paper• scissors • pen• colored

pencils/crayons• glue/tape

– Instructions:• Fold paper lengthwise.• Cut along the fold lines

from the edge to the centerline.

• Color the headings ‘Elements’, ‘Compounds’, and ‘Mixtures’ different colors.

• Use this graphic organizer to list examples of each type of particle.

• Adhere graphic organizer in your science notebook.

Filtration

Separation Technique

Property Used for Separation

Example

Filtration Solubility Separate sand from water

Thin Layer Chromatography (TLC)

Chromatogram of 10 essential oils colored with vanillin reagent.

Separation Technique

Property Used for Separation

Example

Chromatography Size, Polarity, pH Separate component dyes of black ink

Sieving

Separation Technique

Property Used for Separation

Example

Sieving Particle Size Panning for gold (Au)

Magnetic Attraction

Separation Technique

Property Used for Separation

Example

Magnetic Attraction Magnetism Separate ferrous from non-ferrous materials

Decantation

Separation Technique

Property Used for Separation

Example

Decanting Density or Solubility Pour off water from sediment mixture

Evaporation

Separation Technique

Property Used for Separation

Example

Evaporating Solubility and Boiling Point

Driving off water leaving salt behind

TASK: For the scenarios provided, use the decision tree below, and your knowledge of matter, to classify the particles (element, compound, or mixture) described.

An unknown, clear liquid is given to you in a beaker. You transfer the liquid from the beaker to a clean, empty test-tube and begin to heat it. After a while, you see vapors (which on further analysis, you discover are vapors of water) rising from the test-tube, and pretty soon, all that's left are a few crystals of salt stuck to the edges! How would you classify the unknown liquid?

MIXTURE

You have won the world's biggest lottery, for which you are given a huge block of pure, metallic gold. How would you classify this substance?

ELEMENT

A dish is given to you, which contains a blackish-yellow powder. When you move a magnet over it, you are amazed to see black particles (which you find out are iron) fly upwards and get stuck to the magnet. All that's left in the dish is a yellow powder, which you discover to be sulfur.

How would you classify the initial blackish-yellow powder?

MIXTURE

A substance is analyzed in a laboratory, and when viewed under an electron microscope, it is revealed that it contains only one kind of atom. How would you classify the substance?

ELEMENT

This gas is essential for us, and all other aerobic organisms, to survive. We inhale it along with the air we breathe (of which it forms approximately 21%), and it then helps in the oxidation of glucose in our bodies. How would you classify the substance?

ELEMENT

Water is what all life in the world depends on.

How would you classify water?

COMPOUND

A magnesium ribbon is burnt in the air to form the grayish oxide of magnesium - magnesium oxide (MgO). How would you classify this oxide?

COMPOUND

How would you classify the air we breathe?

MIXTURE

These are given 'symbols' like 'Ar', 'Zn', 'W‘, and 'Xe' and are arranged in a table called the periodic table. How would you classify these substances?

ELEMENTS

An unknown, silvery powder has a constant melting point and does not chemically or physically separate into other substances. How would you classify the unknown substance?

ELEMENT

Separating an Unknown Mixture

1. Examine the mixture. Discuss, in your group, how you are going to separate the mixture. Think about the properties and techniques you will use and the order of the steps that you will follow.

2. After you agree on a plan, write this plan in your science notebook. 3. Review the plan with your teacher before you begin to separate the mixture.4. Using the techniques you have selected, separate the mixture. Make observations and record them in your science notebook.

1. Were you successful in separating the components of the mixture? Describe your results.

2. Was the order you used to separate the mixture important? Why?

3.  What was the most challenging part about separating the mixture?

4.  What properties did you use to separate the mixture?

Separating Mixtures

Write a summary report that includes the steps used to successfully separate the unknown mixture into its components.

Include a table that:

• classifies each component separated as a pure substance (element or compound) or mixture;

• identifies the property and technique used to separate the component from the mixture; and

• indicates whether the property used is intensive or extensive.