Discovering Science 7
Unit 3
Chapter 7 - Mixture/Substances
Mixtures vs. Pure Substances
Matter can be either a mixture or pure substances.
Mixture – two or more different types of matter.
Heterogeneous Mixture – made up of two or more part; usually visible to the eye.
Homogeneous Mixture – a mixture in which the parts appear to be the same throughout.
Ex: Clean air, vegetable oil, salt water.
Reading Check – 235 - #1-3
Activity – 235 – 7-1B - Homework
Product
Classification
(Hetero/Homo)
Hetero
Cereal
Reasons
Can see bran and raisins
Pure Substance – matter that is the same throughout. Each part of the substance has the same
properties.
Ex: White sugar, copper, pure water, iron
Reading Check – 237 - # 1-3
Note: Pure Substance/ Mixture diagrams regarding the particle theory of matter are imp. Sketch!
Activity – 238 – 7-1C – Set up 3 stations (OJ, MILK, PEPSI) and allow students to look at them
under a microscope
Checking Concepts – 241 - #1-5
Ms. Marche 2011
Classifying Mixtures
Matter/Mixtures/Pure Substances . . .
Mechanical Mixtures- obviously heterogeneous
Solution – a mixture that is homogeneous
Alloy – solutions that are made of 2 or more metals.
Ex: 22/14/12 karat gold
Ways to tell if a mixture is a solution or heterogeneous:
1. Microscope – solution – you will only see one type of matter
2. Filter – heterogeneous – if anything is caught in the filter
3. Light – heterogeneous – if light passes through and you can see it/particles
Mixtures of Mixtures?


Freshly squeezed OJ
Milk
Reading Check – 245 - #1-4
Check your Understanding – 249 - #1,2,5,6
Checking Concepts – 250 - #1,4,6,8
Ms. Marche 2011
Discovering Science 7
Unit 3
Chapter 8 – Dissolving
Making Solutions: Solutes and Solvents
Solute – the substance that dissolves
Solvent – the substance in which the solute dissolves
Solvents can be solids, liquids and gasses (Chart on page 255)
Solution
Air
Soda water
Solute
Oxygen, carbon
dioxide, and
other gasses
Carbon dioxide
Solvent
Nitrogen
Stage of Solute
Gas
State of Solvent
Gas
Water
Gas
liquid
Activity – 255 – 8-1A - Homework
Soluble – able to dissolve in a certain solvent
Ex: Sugar is soluble in water
Insoluble – unable to dissolve in a certain solvent
Ex: “Motor Oil is insoluble in water”
Reading Check – 257 - #1-3
Activity – 259 – 8-1C – Students do this activity in the lab!
Checking Concepts – 261 - #1-4, 7
Ms. Marche 2011
Concentration and Solubility
Concentrated solution – large mass of dissolved solution for a certain quantity of solvent.
Dilute Solution – has a small mass of dissolved solute for a certain quantity of solvent.
Concentration – quantity of solute that is dissolved in a certain quantity of solvent
Qualitatively – describing the concentration in words
Quantitatively – describing the concentration using numbers
Reading Check – 263 - #2
A pop bottle contains a mixture of concentrated gasses and concentrated liquids. They are all
under pressure!
POP BOTTLE – demonstrate opening a bottle of pop, check out the bubbles ! how does that
work?
CORE LAB – 269
Checking Concepts – 273 – #1,5,8
Checking Concepts – 274 - #1,7,9,11,13
Ms. Marche 2011
Discovering Science 7
Unit 3
Chapter 9 – Separating
Separating Mixtures and Solutions
You separate solutions all the time: cooking, sorting money, laundry !
Mechanical Sorting – separate parts of a mixture based on properties such as particle size
Ex: Floating, magnets
Filtration – removing particles by using filter paper
Ex: Brita Water Filters !
Reading Check – 281 - #2,3
Evaporation – a liquid turning to a gas – solute is left behind
Simple Distillation – removing a solute and solvent from each other. Solution is heated until the
solvent changes state to become a gas. Then the gas changed back to a liquid by cooling.
Example: See photos on page 283
Ms. Marche 2011
Paper Chromatography – separate the colored substances in a mixture such as ink.
CORE LAB – 287 – 289
Checking Concepts – 291- #1,2,6
Activity – Students Read pages 292 – 294
Reading Check – 294 - #1,2
Checking Concepts – 297 - #1,2,7,8
Activity – Students choose 6 questions they want to do on pages 300-301
Ms. Marche 2011