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

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 activity Instructions: 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.Young 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 pair Please 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.(2) For the substance(s) that dissolved, how do you know that the substance is still there? Explain. c.(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 25 marks. 4 of these marks is for your lab participation. Please follow all instructions carefully and stay focused on the activity.