ASSESSMENT March 14 Thursday – practical March 15 Friday – practical March 18 Monday – write-up Bring your Exercise book & Clear file

(Portfolio) on Thursday

Mercury Oxide, is a yellow/orange solid. When it is heated, it turns into mercury and releases oxygen while doing so.

a) How would you test the gas to confirm that it is really oxygen?

b) What type of reaction is this? Give at least TWO reasons to support your answer.

c) Write down the word equation for the reaction.

When finely powdered magnesium is added to hydrochloric acid, it violently reacts, producing magnesium chloride and hydrogen gas.

1. Write down the word equation

2. Write down the balanced symbol equation

3. Is this a combination reaction or not? Explain your answer.

Practical – Zinc & Sulfur Method Prediction – word equation, reason(s) Results – detailed observations Conclusion• word equation• balanced symbol equation• type of reaction + reason(s)• comment on the initial prediction

Example: Hydrogen Peroxide

When heated, hydrogen peroxide (H2O2) slowly turns into water while releasing oxygen gas.

1. What type of reaction is this? Why?

2. Write down the word equation for the reaction

3. Write down the balanced symbol equation for the reaction

Some of the Key Terms• Element – a substance made of just

one type of atom (e.g. O2, H2, Fe, Mg, Cl2, Ag)

• Compound – a substance made of two or more types of atoms (e.g. CO2, H2O, NaCl, CuSO4, Na2CO3)

• Ion – an atom (or a group of atoms) which has gained electrons (anions) or lost electrons (cations)

Water (H2O) is separated into hydrogen gas and oxygen gas by using two strongly, oppositely charged electrodes. In this reaction:1. What is the reactant?

2. What are the products?

3. Write down the word equation for the reaction

4. Write down the balanced symbol equation for the reaction

5. Is this a combination reaction?

Hydrogen gas and oxygen gas reacted together to form water.

1. Write down the word equation for the reaction

2. Write down the balanced symbol equation for the reaction

3. What type of reaction is this? Why?

Electrolysis

Define the term “Isotopes”

These are three common carbon isotopes. How many protons, electrons and neutrons are there in an atom of each isotope?

Protons Electrons NeutronsCarbon-12Carbon-13Carbon-14

Decomposition Reaction• It is the separation of a chemical

compound into more than one elements or compounds.

• AB → A + B• It is sometimes defined as the

opposite of combination reaction.

Example: Hydrogen Peroxide (H2O2)

Catalysta) Catalysts speed up chemical

reactions

b) Catalysts DO NOT REACT

c) Catalysts do not get used up

d) Different catalysts are used for different reactions

Gas Tests• Carbon dioxide – Limewater Test

• Hydrogen – ‘Pop’ Test

• Oxygen – Splint Test

Test for Carbon Dioxide – Limewater Test

Test for Hydrogen – Pop Test

Test for Oxygen – Splint Test

Practical:

Hydrogen Peroxide (H2O2) and Manganese Dioxide (MnO2)

Method

Put a spatula of potassium permanganate and 100 ml of 3% hydrogen peroxide solution into a conical flask

If any gas is produced, test what type of gas it is

Prediction – word equation, reason(s) Results – detailed observations Conclusion• word equation• balanced symbol equation• type of reaction + reason(s)• comment on the initial prediction

Result / Conclusion:• Describe what you observed

• Describe what gas has been produced

• Describe why this reaction is a decomposition reaction

• Write down the word equation

• Write down the balanced symbol equation

Elephant Toothpaste!!

Gas Tests• Carbon dioxide – Limewater Test

• Hydrogen – ‘Pop’ Test

• Oxygen – Splint Test

Test for Carbon Dioxide – Limewater Test

Test for Hydrogen – Pop Test

Test for Oxygen – Splint Test

When baking soda (sodium bicarbonate) was heated, water, sodium carbonate and an unknown gas were produced.

1) What do you think the unknown gas may be?

2) How would you identify this gas?

3) Write down the word equation for this reaction.

4) Write down the balanced symbol equation.

5) What type of reaction is this? Why?

Practical: Heating Sodium Bicarbonate (baking soda) Method

1. Heat up a spatula of baking soda in a test tube

2. Test and identify what type of gas is being produced

Lime water test

How to collect gas for splint test or pop test

Prediction – word equation, reason(s) Results – detailed observations Conclusion• word equation• balanced symbol equation• type of reaction + reason(s)• comment on the initial prediction

Practical 2: Heating Potassium Permanganate (KMnO4)

Method

1. Heat up a spatula of potassium permanganate in a test tube

2. Test and identify what type of gas is being produced

Prediction – word equation, reason(s) Results – detailed observations Conclusion• word equation• balanced symbol equation• type of reaction + reason(s)• comment on the initial prediction

How do we predict which products will be produced???• Combination – put the reactants

together• Precipitation – solubility rules• Displacement – activity series• Decomposition – look at the formula of

the reactant

DEMO – Zinc & IodinePart A

a) Mix 10 ml of ethanol and 0.5 g of powdered iodine together and measure the temperature.

b) When all of the iodine is dissolved, add 0.5 g of zinc powder and measure the temperature as it reacts.

Part B

a) Filter the solution into a 100 ml beaker and add about 20 ml of distilled water.

b) Put the graphite electrodes over the beaker so that the electrodes are immersed in the solution.

c) Connect the electrodes to the power supply then turn it on.