7H Solutions and 7F Simple Chemical Reactions

Solutions vocabulary When you mix salt and water to get salty water. Which substance is the Solute? Solvent? Solution?

Dissolving Which words means something will dissolve in a solvent? Which word means that something will not dissolve in a solvent?

SolubleInsoluble

Saturation Is there a limit of how much solute will dissolve in a solvent? What is a saturated solution? How do we know is a solution is saturated?

Saturation Experiment Aim: To investigate how the maximum number of spatulas of salt dissolved changes with volume of water. Variables Independent: Range:Values: Dependent: Control:

Results Volume of water (ml)Number of spatulas dissolved

Upd8 activity What is this?

Read the information in the cards Put them in order to show how you get kidney stones.

Mass of solutions When you add a solute to a solvent what happens to the volume of the solution? When you add 5g of sugar to 100g of water what will the total mass be? Why?

Results Name of solvent Mass of solvent (g) Name of solute Mass of solute (g) Mass of solution (g)

Separation How can we separate an insoluble solid and water? How can we separate inks in pens? How can we separate salt and water? How can purify water ?

7F Simple Chemical reactions

Chemical and Physical changes What is a physical change? Give an example. What is a chemical change/reaction? Give an example. What is the difference between chemical and physical changes?

Can you ‘uncook’ the egg, bacon or toast? NO. The changes are irreversible. This means it can’t be changed back into what you started with.

Can you change water into ice? Can you change ice into water?

The changes from water to ice, and back again are reversible. This means you can get back to what you started with. Reversible changes are usually PHYSICAL reactions. Irreversible changes are usually CHEMICAL reactions. The important thing to remember is… CHEMICAL REACTIONS MAKE NEW THINGS.

Chemical or physical?

Chemical reactions What are the signs of a chemical reaction?

Signs of a chemical change… Change in colour Change of temperature Bubbles of gas

CHEMICAL/PHYSICAL CHANGE STATIONS Do the experiments and write about what you see. Lots of detail please, at least 4 sentences per station.

Chemical n physical changes Science tube video (13 mins)

Gas tests Name 4 gases How do you test for Oxygen? How do you test for Carbon dioxide? How do you test for Hydrogen?

Which picture shows the test for which gas? (Oxygen, Hydrogen, Carbon dioxide)

Important words Splintlime waterrelight lit splintglowing splint Cloudymilky“squeaky pop”

Metals and acids Name 3 metals Name 3 acids What happens when a metal reacts with an acid Complete this equation Metal + Acid _______ +______

A reaction that usually makes hydrogen is the reaction of a metal and an acid. You are going to test several metals to see if they react with the acid. Remember you are looking for bubbles! Fill in the table in your booklet.

Copy and complete this table to describe the reactions of metals with acid MetalReaction with acid Copper Iron Magnesium Zinc

We are going to test the gas that has been given off to see if it is hydrogen. What is the test for hydrogen gas? Think back to the video.

Homework Glue in and complete worksheets 7Fa and 7Fd Make a table with 2 columns to give 5 examples of physical and 5 chemical changes that happen in your kitchen PhysicalChemical e.g. when I take ice cream from the freezer it melts e.g. When I cook an egg it solidifies but cannot change back to a liquid.

Acids and carbonates Name two carbonates Complete this equation Acid + carbonate ______ + _______ + ________

A reaction that makes carbon dioxide is the reaction of a carbonate and an acid. These things are all carbonates.

Copy and complete this table to describe the reactions of carbonates with acid CarbonateReaction with acid Calcium carbonate (marble) Chalk Indigestion tablet Bicarbonate of soda

We are going to test the gas that has been given off to see if it is carbon dioxide. What is the test for carbon dioxide gas? Think back to the video.

Optional bath bomb activity If time permits

The reaction that makes carbon dioxide gas can be useful. We can use the reaction to make a fizzy bath bomb.

Follow the instructions: Weigh out 15g of citric acid, bicarbonate of soda and cornflour. Mix these ingredients and put them in a cup. Measure 9ml of oil in a measuring cylinder using a funnel. Add 5 small drops of colour and some of the smelly oil. Make the total volume 10ml in your measuring cylinder. Add the wet ingredients to the dry ones a bit at a time, and mix them up well. Now make the mixture into a ball shape in your hands (this is messy!). Leave it to dry.

Burning What three things are needed for a substance to burn? Complete the equation Magnesium + Oxygen _____________ Which chemicals are produced when we burn a fossil fuel or candle? (hydrocarbon) Complete the equation Hydrocarbon + Oxygen _______ + ______

Remember the fire triangle from 7I? If we burn something in pure oxygen rather than just in the air the reaction is bigger and faster.

A chemical reaction happens when something burns. Watch what happens when the magnesium burns. DO NOT LOOK DIRECTLY AT THE LIGHT! What is left behind once all the metal has burned? The white stuff is a new thing – a chemical reaction has happened.

What is made when a candle burns? When a candle burns, a chemical reaction happens. We can test to see what new things are made.

What happens when you put a beaker upside down over the candle? What is the beaker stopping? oxygen

What is inside the beaker? There is a GAS inside the beaker. How can we find out what gas it is? Put the beaker over the candle until it goes out. Then pour some limewater into the beaker and swirl it round. What happens?

Hold the beaker over the candle, but not so close that it goes out. What is now inside the beaker? water vapour

We have proved what is made when the candle burns. Copy and complete the sentence: When we put the beaker over the candle it ________ ______. This is because the beaker stopped _______________ getting to the flame. We know the fire made ___________ __________ because the limewater went ____________. We know the fire made water vapour because there was ____________________ on the beaker. Words to use: oxygen carbon dioxide went out condensation cloudy

Fireworks