Week 7

1. Observe the experiment performed by the teacher and answer:

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a) Draw the experiment before and after. Explain what happened

b) Why did the water go up?

c) How is this experiment related to the topic of burning reactions?

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2. Watch the part of the video shown by the teacher (It's an extract from the series "Anne with an E"). Then explain why the girl could solve the problem in a faster way.

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3. What is the right thing to do in case that a person gets on fire? Why can't we use something to blow the fire away?  Need help with this answer? Check this VIDEO

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4. Investigate 3 uses of combustion reactions in real life. Explain them with your own words

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5. Visit the CHEM website and answer: What do combustion reactions release? Write the chemical equation of a combustion reaction. 

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BONUS POINT: Watch the VIDEO about car engines and explain step by step in your own words how do engines use gasoline to make the car work?

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You probably learned about the pH scale last year and now you remember the basic concept: Acids and bases are two groups of chemical compounds with opposite properties that are encountered frequently in the laboratory and in everyday life. Acids, bases, and the products of their reactions are vital to many life processes and are invaluable to industry and agriculture.

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During this class, we will learn how acids react with other substances to create different products, specifically how acids react with metals, hydroxides and carbonates. We will learn the general equations for these reactions and will analyze a few cases.

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Let's start with a short presentation:

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Use any search engine to find the name, formula and use of 5 acids.

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1. Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen. Let's analyze this reaction:

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a) Write the word equation for this reaction

b) What class of reaction is it? (from the 3 types you learnt today)

c) What are the reactants?

d) What are the products?

e) Write the chemical equation of this reaction (Hydrochloric acid is HCl)

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2. Calcium chloride, water and carbon dioxide are produced when calcium carbonate and hydrochloric acid react. 

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a) Write the word equation for this reaction

b) What class of reaction is it? (from the 3 types you learnt today)

c) What are the reactants?

d) What are the products?

e) Write the chemical equation of this reaction (Hydrochloric acid is HCl)

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3.. Lithium nitrate and water are produced when nitric acid and lithium hydroxide react. Let's analyze this reaction:

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a) Write the word equation for this reaction

b) What class of reaction is it? (from the 3 types you learnt today)

c) What are the reactants?

d) What are the products?

e) Write the chemical equation of this reaction (Nitric acid is HNO3)

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4. Look at the following reaction:

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CuCO3   +    HCl                             CuCl   +    H2O   + CO2

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a) Write the word equation for this reaction

b) What class of reaction is it? (from the 3 types you learnt today)

c) Does this reaction produce a gas? explain

d) Which compound is a salt?

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5. We have this reaction:

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Zn   +     H2SO4                                ZnSO4       +    H2

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a) Write the word equation for this reaction (H2SO4 is sulfuric acid)

b) What class of reaction is it? 

c) Does this reaction produce a gas? explain

d) Which compound is a salt?

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A lot of chemical reactions are useful - for example, cooking and the reactions that happen inside the body. But some reactions are not very useful. An example of a reaction that is not useful is rusting (when something gets rusted, or in Spanish cuando algo se oxida). Today we will learn more about the conditions for some metals to get rusted and how to prevent this undesirable reaction:

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1. Visit the Tought.Co website and summarize in your notebook, when does rust form?​

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2. In the same website, under the title "Preventing rust"

find the information about why is rust undesirable.

and what happens to iron when it gets rusted?

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3. There is an experiment to prove what is needed for rust to occur, read the experiment :

 

Clean iron nails should be placed in each of the three​

test jars labelled A, B, and C:

• Fill test tube A with tap water and cork it.

• Fill test tube B with hot distilled water, then add roughly

• 1ml of oil and cork it. The oil will float on the surface of

• the water, keeping the air from being in touch with the water.

• Fill test tube C with anhydrous calcium chloride and cork it.

• Any moisture in the air will be absorbed by anhydrous calcium chloride.

• Allow a few days for these test tubes to settle before observing.

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Result: Iron nails rust in test tube A but not in test tubes B and C,

according to the results. The nails in test tube A corroded because

they were exposed to both air and water. Test tube B’s nails are solely

to water, but test tube C’s nails are exposed to dry air.

 

a) Write one conclusion about the factors needed for rust to occur

b) Why is the same type of nail used in all test tubes?

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4. Visit the Byjus website and explain 2 methods used to prevent rusting.

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