Mention any two (2) areas of application of scientific procedures.

1. Mention any two (2) areas of application of scientific procedures. (2 mk)
2. List down all steps of scientific procedure. (4 mk)

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Study the summary diagram of the change of matter from one state to another and then answer the questions that follow: LIQUID B D C E SOLID GAS A Identify the name of change indicated by letters A

1. Identify the name of change indicated by letter A (1 mk)
2. Identify the name of change indicated by letter B (1 mk)
3. Calculate the oxidation number (state) of underlined elements KClO 3 (0 mk)
4. Calculate the oxidation number (state) of underlined elements CO 2- 3 (0 mk)
5. Identify the name of change indicated by letter C (1 mk)
6. Identify the name of change indicated by letter D (1 mk)
7. Identify the name of change indicated by letter E (1 mk)

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Define the change represented by letter A

1. Are used to improve the quality and quantity of crops grown. (1 mk)
2. Define the change represented by letter A (2 mk)
3. Special room or building that is designed and used for scientific experiment. (1 mk)
4. Usually used to accurately measure and dispense liquid. (1 mk)
5. It is among the causes of accident in the laboratory. (1 mk)
6. The injury that causes a change in the colour of the skin. (1 mk)
7. It produces a black substance known as soot. (1 mk)
8. Protons and neutrons. (1 mk)
9. A group of atoms with unpaired electrons. (1 mk)
10. The ability or capacity of doing work. (1 mk)
11. The regular periodic changes of elements due to their atomic number (1 mk)

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Define the change represented by letter A

1. Heat is the ________________ of being ________________________. (1 mk)
2. Mention one example of substance that can undergo the change represented by letter A (1 mk)
3. Define the change represented by letter A (2 mk)
4. Weed killers are chemical _________________ that are used to destroy unwanted ___________________________ which are harmful to crops. (1 mk)
5. Mention one example of substance that can undergo the change represented by letter A (1 mk)
6. Fire is the state or process of _______________ in which ignited material combine with ____________________ and give off light, heat and flame. (1 mk)

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a) What is a chemical formula? b) Differentiate between molecular formula and empirical formula. c) A certain compound contains 1.59% hydrogen, 22.22% nitrogen and 76.19% oxygen. Calculate its i) Empirical formula ii) Molecular formula, if its relative molecular mass is 63. iii) Name the compound

1. What is a chemical formula? (2 mk)
2. Differentiate between molecular formula and empirical formula. (3 mk)
3. Calculate its Empirical formula (4 mk)
4. Molecular formula, if its relative molecular mass is 63. (3 mk)
5. Name the compound (3 mk)

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iii) Write two (2) areas where renewable energy can be used. ______________________________________________________ ______________________________________________________

1. Empirical formula (0 mk)
2. What is biogas? (2 mk)
3. Why is biogas mostly encouraged to use as fuel compared to other types of fuel. (3 mk)
4. What is renewable energy? (2 mk)
5. Write two (2) areas where renewable energy can be used. (2 mk)
6. Name the compound (0 mk)

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iii) Mention any two (2) areas of application of scientific procedures. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________

1. What is scientific procedure? (2 mk)
2. Mention any two (2) areas of application of scientific procedures. (2 mk)

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Outline any two (2) significance of chemical symbol. Write the symbols of Sodium, Potassium and Beryllium.

1. Unsaturated solution (1 mk)
2. Give any two (2) differences between mixture and compound. (2 mk)
3. Outline any two (2) significance of chemical symbol. (1 mk)
4. Write the symbols of Sodium, Potassium and Beryllium. (1 mk)
5. Emulsion (1 mk)

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ii) CO 2- 3

1. Give any two (2) differences between mixture and compound. Mixture Compound (2 mk)
2. Calculate the oxidation number (state) of underlined elements i) KClO 3 (2 mk)
3. Calculate the oxidation number (state) of underlined elements ii) CO 2- 3 (2 mk)
4. By using and x, Show how potassium chloride is formed. (4 mk)
5. List down three (3) properties of electrovalent compound. (3 mk)
6. How an ion is formed? (2 mk)
7. (2 mk)

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a. i. Define periodic table. ii. State modern Periodic law. iii. Below are groups of elements, arrange them in their respective position in the periodic table as shown below I II III IV V VI VII O ( Li, B, C, N, O, F, Ne, Mg, Al, Si, P, Cl)

1. Define periodic table. (1 mk)
2. Define periodic table. (1 mk)
3. State modern Periodic law. (1 mk)
4. Below are groups of elements, arrange them in their respective position in the periodic table as shown below I II III IV V VI VII O ( Li, B, C, N, O, F, Ne, Mg, Al, Si, P, Cl) (4 mk)
5. Below are groups of elements, arrange them in their respective position in the periodic table as shown below I II III IV V VI VII O ( Li, B, C, N, O, F, Ne, Mg, Al, Si, P, Cl) (4 mk)

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a) Draw the warning sign which represent i) Harmful substance ii) Irritant substance iii) Oxidant b) i) Why it is important to put in a place safety measures in a laboratory? ii) Why all persons working in a laboratory required to wear appropriate protective clothing? c) What is the aim of using fume chamber in the laboratory?

1. Draw the warning sign which represent i) Harmful substance ii) Irritant substance iii) Oxidant (3 mk)
2. Why it is important to put in a place safety measures in a laboratory? (2 mk)
3. Why all persons working in a laboratory required to wear appropriate protective clothing? (2 mk)
4. What is the aim of using fume chamber in the laboratory? (1 mk)

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i) Explain briefly the three (3) states of matter. ii) Study the summary diagram of the change of matter from one state to another and then answer the questions that follows: LIQUID B D C E SOLID GAS A Identify the name of change indicated by letters A ________________________________________________________________ B ________________________________________________________________ C ________________________________________________________________ D ________________________________________________________________ E ________________________________________________________________

1. Study the table which shows reaction of some metals with oxygen, then fill the blanks Metal How it burns Colour of flame Name of product formed Potassium White powder Calcium White solid Zinc Slowly with a dull red flame (0 mk)
2. Study the table which shows reaction of some metals with oxygen, then fill the blanks (0 mk)
3. i) Explain briefly the three (3) states of matter. (0 mk)
4. Outline two (2) physical properties of oxygen. (0 mk)
5. Study the table which shows reaction of some metals with oxygen, then fill the blanks | Metal | How it burns | Colour of flame | Name of product formed | |---------|----------------------------|-----------------|------------------------| | Potassium | | | | | Calcium | | White solid | | | Zinc | Slowly with a dull red flame | | | (0 mk)
6. Study the summary diagram of the change of matter from one state to another and then answer the questions that follows: LIQUID B D C E SOLID GAS A Identify the name of change indicated by letters A ________________________________________________________________ B ________________________________________________________________ C ________________________________________________________________ D ________________________________________________________________ E ________________________________________________________________ (0 mk)
7. List down any two (2) industrials uses of oxygen (0 mk)
8. Outline two (2) physical properties of oxygen. (0 mk)
9. List down any two (2) industrials uses of oxygen (0 mk)
10. Explain briefly the three (3) states of matter. (0 mk)

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