Introduction to Solutions (Chapter 5) 7 SCIENCE
How do solutions relate to matter? Atoms make up all matter on earth; therefore solutions are made from atoms When atoms combine they are called chemical compounds Ex: What atoms make up the chemical compound water? These chemical compounds cannot be separated by physical processes like squeezing, filtering etc If a substance can be broken down by physical processes it is called a mixture
Mixtures A mixture is a combination of substances that can be separated by physical means Ex: boiling saltwater to separate the salt from the water Two types of mixtures: Heterogeneous Homogeneous
Heterogeneous Mixtures Hetero = different The substances in a heterogeneous mixture are not mixed evenly, so different parts have different compositions Different parts of the mixture are easy to see Ex: watermelon and seeds Ex: oil in water
Homogeneous Mixtures Homo = same Made up of 2 or more substances and one appears to ‘disappear’ into the other Not easy to see the different parts Ex: Saltwater – you cannot see the salt as different than the water Ex: Nestea powder into water cannot see the powder is different Also called a solution
Solutions When you mix 2 or more substances together, the substance that seems to disappear (dissolves), is called the solute The substance that dissolves the solute is called the solvent Ex: Sugar and coffee Which is the solute? Solvent?
Mixtures activity Instructions:You will travel to each mixture station and be responsible for creating a mixture with your group, record observations and answer questions individually 1) Read and follow the instructions from Ms.Young and create a hypothesis for each substance. 2) Test your hypothesis by creating a mixture at each station with 100mL of water and half a teaspoon of each substance. 3) Stir until there is no change in the mixture. 4) Record observations for each substance. 5) Please answer the following questions on the back of your observation paper: Which substances dissolved into the water when you stirred? For the substance(s) that dissolved, how do you know that it is still there? How could you figure this out? Do you think the ability of water to dissolve many substances is useful in our lives? Explain why/why not.