Types of Solutions

7SCIENCE

Review

• What is a mixture?– Combination of substances

• What are the two types of mixtures?– Homogeneous– heterogeneous

• What is a solution?– A homogeneous mixture

• What is the difference between a solute and a solvent?– Solute is what disappears or dissolves into the solvent

Types of Solutions• Similar to the 3 states of matter, there are 3

types of solutions:– Solid – Liquid– Gaseous

• One specific type of liquid solution is the aqueous solution – Water is the solvent

Solid solutions

• Solvent is a solid• Most common are solid – solid solutions • Solid-solid solutions of metal are called

alloys – Jewellery, faucet/sink, instruments

• Gas-solid combination is freezing water and air bubbles are trapped frozen in the ice

Let’s Watch and Review…

http://youtu.be/VTmfQUNLlMYhttp://youtu.be/M5Tx99IN_K4

Review Questions• The majority component of a

solution is the __________. • The minority component of a

solution is the __________. • Decide whether the following

statement is true or false, and then explain why: There is no such thing as a universal solvent.

• An aqueous solution is a solution in which the solvent is __________.

• A solution in which there is a lot of solute relative to the solvent is __________.

• A solution in which there is little solute relative to the solvent is __________.

• How is the concentration of solute in a solution measured?

1. Compare and contrast the solute and solvent of a solution.2. Describe an example of a gaseous solute dissolved in a liquid solvent. 3. Explain the expression “like dissolves like,” and give an example. 4. Outline how sodium chloride dissolves in water.

Liquid solutions• Solvent is a liquid • Solute can be a liquid, solid or gas• Examples:– liquid-gas: soda– liquid-solid: saltwater, milo and milk– Liquid-liquid: oil and vinegar (salad dressing), perfume

Aqueous solutions

• Aqua = water• Water is the solvent• Called the “universal solvent”– Because it can dissolve many

solutes• WHY!?– Water is made of the negatively

charged oxygen atom and two positively charged atoms – these can attract many kinds of atoms and dissolve more easily

Gaseous solutions

• Solvent is a gas• Small amounts of one gas are dissolved in a

larger amount of gas • Example: Air– 78% nitrogen– 20% oxygen– Other gases

Aqueous Mixtures activityInstructions: You will travel to each mixture station and create a mixture with your partner. Remember to record observations!

1) Read and follow the instructions from Ms. Marcum and create a hypothesis for each substance. Remember to explain why in a hypothesis as well!

2) Test your hypothesis by creating a mixture at each station with 30mL of water and half (1/2) a spoonful of each substance. **Please do not mix up spoons from different stations, or this will contaminate and ruin the experiment.**

3) Stir until there is no change in the mixture. Record observations for each substance in a table. Your table should have the following:1 mark: Title 1 mark: Station # (1-5)10 marks: Hypothesis (for each substance)5 marks: Observations

Questions to answer – one per pairPlease answer the following questions on the back of your observation paper: YOU DO NOT NEED TO WRITE OUT THE QUESTIONS.a. (5) Which substances dissolved in the water when you

stirred?b. (5) Try and identify each of the solutes (Station 1 was….etc).c. (2) For the substance(s) that dissolved, how do you know

that the substance is still there? Explain.d. (2) Do you think the ability of water to dissolve many

substances is useful in our lives? Explain why/why not.

This lab activity will be for 30 marks. 4 of these marks is for your lab participation. Please follow all instructions carefully and stay focused on the activity.