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Science 8 · Unit 8: Chemical reactions · Cambridge Lower Secondary Science Stage 8

8.1 Exothermic reactions

18 questions · e.g. Name two control variables in that investigation.

Practice

Questions

  1. 1. What happens to the temperature in an exothermic reaction?

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  2. 2. In an exothermic reaction, where is energy transferred?

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  3. 3. What is the word equation for magnesium and sulfuric acid?

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  4. 4. Sofia tests whether more magnesium ribbon makes a bigger temperature rise. What is the independent variable?

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  5. 5. In that investigation, what is the dependent variable?

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  6. 6. Name two control variables in that investigation.

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  7. 7. Ribbon 0.5 cm, 1.0 cm and 1.5 cm all raised the temperature by about 17 °C. Can they confirm their prediction?

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  8. 8. How can heat loss from the test tube be reduced?

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  9. 9. How can results be made more reliable?

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  10. 10. Zara puts a small piece of metal X into 10 cm³ of acid. Arun puts a bigger piece of metal Y into 10 cm³ of the same acid. Which variable did they change that they should have kept the same?

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  11. 11. Metal X raised the temperature 2 °C and Y raised it 6 °C. What can they conclude?

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  12. 12. When potassium reacts with water, what is chemical energy changed into?

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  13. 13. What is the word equation for potassium and water?

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  14. 14. Which type of graph suits results for four different metals (A, B, C, D)?

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  15. 15. Which is an exothermic process?

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  16. 16. What three things are needed for burning?

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  17. 17. What is an oxidation reaction?

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  18. 18. Hydrogen burns in a model rocket. What is the product?

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