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Year 7 Science Revision

7A Cells: The Body’s Building Bricks

Q1. Organ Cell Body Tissue Arrange the previous body parts in order (which part is composed of which part) Give 2 examples of each.

Q2. Fill in the labels on the following microscope picture. Mention the function of each part.

Q3. A microscope with 2 eyepieces; x5 and x10, and 3 objective lenses x10, x20 and x40. What are the magnifications you can get from using this microscope?

Q4. A ladybird of 4mm length. It was drawn on a paper as 4 cm long. What is the scale factor used?

Q5. What are the common parts that are found in both plant cell and animal cell? What is the function of each part?

Q6. What are the special cell parts that can only be found in plant cells? What is the function of each part?

Q7. What is the difference between normal cells and specialized cells? Q8. Give the special feature and the function of each of the following specialized cells; goblet

cells, ciliated epithelial cells, nerve cells, red blood cells and root hair cells. Where’s each of these cells found?

Q9. How does a cell divide? Q10. What are the steps of sexual reproduction in the flower of a plant?

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7B Reproduction

Q1. What is the name of the male sex cell? Fill in the labels on its diagram.

Q2. What is the name of the female sex cell? Fill in the labels on its diagram.

Q3. What do we call fusion between a male sex cell and a female sex cell? Q4. Compare between fertilization in humans, birds and amphibians in terms of; where does

fertilization happen?, where does the fertilized egg develop?, where are the eggs laid?, the number of eggs produced, do eggs have a soft or a hard shell?, do parents look after their young?

Q5. Fill in the labels on the following diagram.

Q6. Fill in the labels on the following diagram.

Q7. Where does fertilization happen? Where does an embryo develop? Q8. Mention the body parts through which the sperm goes until it fertilizes the egg. Q9. What is the difference between identical twins and non-identical twins? Q10. Discuss what happens during the following days of the menstrual cycle; day 1, days 7- 12,

days 13- 14, days 15- 20 and days 21- 28.

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Q11. Complete the labels on the following diagram.

Q12. What’s the job of: a) The umbilical cord b) The amniotic fluid

Q13. Mention two substances that pass from the baby to the mother. Q14. Mention two useful substances that pass from the mother to the baby. Q15. Mention two harmful substances that can pass from the mother to the baby. Q16. What are the steps of labour? Q17. What is afterbirth? Q18. What is the name of the gland that makes milk in the human body? Q19. Write down 2 differences between human milk and cow’s milk. Q20. What are the secondary sexual characters? Q21. Write down 2 changes that happen during adolescence to:

a) Boys only b) Girls only c) Both boys and girls

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7E Acids and Alkalis

Q1. Give the names of 3 acids and 2 alkalis that you can find at home. Are they mild or strong?

Q2. Give the names of 2 strong acids and 2strong alkalis. What are their uses?

Q3. Draw 5 Hazard Symbols. Give the meaning of each one of them.

Q4. Give the names of 4 natural indicators. What are they extracted from?

Q5. Draw a table about the 4 natural indicators and the colour changes they give with acids,

alkalis and neutral solutions.

Q6. Mention the colours given by the Full range Universal Indicator when used with strong acid,

weak acid, strong alkali, weak alkali and a neutral solution.

Q7. What is the pH scale? Mention the pH scale range for strong acid, weak acid, strong alkali,

weak alkali and a neutral solution.

Q8. What is the general equation for neutralization? Give an example of a neutralization

reaction.

Q9. What is the meaning of “Indigestion”? How can you cure it? Give examples of the remedies

used.

Q10. How does each of the following make use of neutralization reaction:

a. Toothpaste

b. Making cakes rise

c. Acid rain

d. Soil treatment

Q11. For each question you have to decide if the statement is true for acids or alkalis. a) pH1? b) Lemon juice? c) Oven cleaner? d) pH14? e) Turns litmus paper red? f) Sodium hydroxide? g) Turns universal indicator purple? h) Feels soapy? i) Has higher pH than water? j) Vinegar?

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Q12. Circle the correct answer. An (acid/ alkali) with pH1 was tested with a full range indicator. Its colour turned (red/ orange). To decrease its acidity a solution of (nitric acid/ sodium hydroxide) was added. When equal amounts of these solutions were mixed the pH of the solution became (7/14) and turned the indicator (green/ blue). This reaction is called (combustion/ neutralization).The two products of this reaction are (carbon dioxide/ salt) and (hydrogen/ water).

Q13. Fill in the blanks in the following word equations: a) Hydrochloric acid + ____________________ sodium chloride + water

b) __________________ + calcium hydroxide calcium nitrate + water

c) Phosphoric acid + sodium hydroxide _______________ + _________________

Q14. Fill in the table below to show the colour of the different indicators in acidic, alkaline and neutral solutions.

Indicator Acid Alkali Neutral Red litmus paper

Blue litmus paper

Red cabbage indicator

Universal indicator

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7F Simple Chemical Reactions

Q1. What is a chemical reaction? What is the difference between chemical and physical

changes?

Q2. Write down one example of an everyday chemical reaction and an example of a physical

change.

Q3. What is the equation for the reaction between an acid and a metal? Give an example.

Q4. What is the equation for the reaction between an acid and a carbonate? Give an example.

Q5. What is the equation for burning? Give an example.

Q6. What is the equation for burning of fuels? Give an example.

Q7. Draw the fire triangle.

Q8. Explain about the candle burning process, giving its steps in details.

Q9. Does covering a burning candle with a jar affect its burning time? Explain why.

Q10. What are the main gases found in air? Give their percentages.

Q11. George burned some propane and collected the products in a test tube.

a) What is the name of this reaction?

b) What is the gas needed for this reaction?

c) Write the word equation of this reaction.

d) What are the reactants?

e) What are the products?

f) What is the evidence that a chemical change had happened?

g) Describe the TEST to identify the gas produced and its RESULT?

h) Propane is used in a Bunsen burner.

i) How can you control the size of the flame?

ii) How can you control the temperature of the flame?

iii) What is the colour of the hot flame?

Q12. Give evidences that the reactions below are examples of chemical changes.

a) Hydrochloric acid reacting with calcium carbonate.

b) Sulphuric acid reacting with magnesium.

c) Iron reacting with oxygen gas.

Q13. Describe the TEST used to identify hydrogen gas and its RESULT.

Q14. Describe the TEST used to identify oxygen gas and its RESULT.

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Q15. Complete the following chemical reactions:

a) Nitric acid + Iron → ______________

b) ________________ + Oxygen → Carbon dioxide + Water.

c) Copper + _________________ → Copper oxide

d) Sodium carbonate + _______________ → Sodium chloride + Water + ______________

Q16. Mention if the statements below are examples of physical or chemical changes.

a) Wax melting as being heated.

b) Glass breaking

c) Posters fading

d) Candle burning

e) Petrol evaporating

f) A metal corroding