Mixtures, Elements and Compounds practice exercise 1

A boarding school in Nyeri notices that when they use water from their borehole, beans take much longer to cook compared to when they use rainwater. Explain why this happens and suggest a solution the school can adopt. (2 marks)

At a flower farm in Naivasha, plants started showing signs of nutrient deficiency after a switch to soft water irrigation. What should the farm manager consider doing? (1 mark)

An industrial cleaning company uses water from two towns. In Town A, cleaning soap lathers easily; in Town B, it doesn’t. What should they conclude, and what action should they take?  (2 marks)

An industrial cleaning company uses water from two towns. In Town A, cleaning soap lathers easily; in Town B, it doesn’t. What should they conclude, and what action should they take?  (2 marks)

An industrial cleaning company uses water from two towns. In Town A, cleaning soap lathers easily; in Town B, it doesn’t. What should they conclude, and what action should they take?  (2 marks)

Study the diagram of two bicycles: Bicycle A stored in a dry garage, Bicycle B left outside in rain. Both are made of iron. Explain why rusting differs between them and suggest preventive measures. (2 marks)

Study the diagram of two bicycles: Bicycle A stored in a dry garage, Bicycle B left outside in rain. Both are made of iron. Explain why rusting differs between them and suggest preventive measures. (2 marks)

Study the diagram below of two bicycles: Bicycle A stored in a dry garage, Bicycle B left outside in rain. Both are made of iron. Explain why rusting differs between them and suggest preventive measures. (3 marks)

The school’s iron water tank started leaking due to rust. What alloy would you recommend they use for the new tank, and why? (1 mark)

The school’s iron water tank started leaking due to rust. What alloy would you recommend they use for the new tank, and why? (1 mark)

The school’s iron water tank started leaking due to rust. What alloy would you recommend they use for the new tank, and why? (1 mark)

A factory in Thika replaces its water supply with soft water to improve equipment efficiency. After 6 months, corrosion is detected in metal pipes. Explain one advantage the factory experienced and one major disadvantage they are now facing.  (2 marks)

A factory in Thika replaces its water supply with soft water to improve equipment efficiency. After 6 months, corrosion is detected in metal pipes. Explain one advantage the factory experienced and one major disadvantage they are now facing.  (2 marks)

Why does Magnesium (2.8.2) burn brightly in air while Argon (2.8.8) does not react?

Why does Magnesium (2.8.2) burn brightly in air while Argon (2.8.8) does not react?  (1 mark)

Why does Magnesium (2.8.2) burn brightly in air while Argon (2.8.8) does not react?  (1 mark)

Potassium helps ripen bananas in Kisii County. If a potassium atom has 19 protons and 20 neutrons, what is its mass number?

Potassium helps ripen bananas in Kisii County. If a potassium atom has 19 protons and 20 neutrons, what is its mass number?  (1 mark)

Potassium helps ripen bananas in Kisii County. If a potassium atom has 19 protons and 20 neutrons, what is its mass number?  (1 mark)

Potassium helps ripen bananas in Kisii County. If a potassium atom has 19 protons and 20 neutrons, what is its mass number?  (1 mark)

Study the diagram showing a water pipe buried underground. One pipe is wrapped with plastic coating, the other is bare iron. Which pipe will rust faster? Diagram description: Pipe A is wrapped in plastic; Pipe B is bare and buried directly in soil.

The diagram below shows a water pipe buried underground. One pipe is wrapped with plastic coating, the other is bare iron. Which pipe will rust faster?  (1 mark)

The diagram below shows a water pipe buried underground. One pipe is wrapped with plastic coating, the other is bare iron. Which pipe will rust faster?  (1 mark)

The diagram below shows a water pipe buried underground. One pipe is wrapped with plastic coating, the other is bare iron. Which pipe will rust faster?  (1 mark)

Wanjiku is attending a Kikuyu traditional wedding and wants to wear a necklace that shows wealth and status. Which metal is most appropriate for her jewellery?

Wanjiku is attending a Kikuyu traditional wedding and wants to wear a necklace that shows wealth and status as shown below. Which metal is most appropriate for her jewellery?  (1 mark)

Wanjiku is attending a Kikuyu traditional wedding and wants to wear a necklace that shows wealth and status as shown below. Which metal is most appropriate for her jewellery?  (1 mark)

Wanjiku is attending a Kikuyu traditional wedding and wants to wear a necklace that shows wealth and status as shown below. Which metal is most appropriate for her jewellery?  (1 mark)

Wanjiku is attending a Kikuyu traditional wedding and wants to wear a necklace that shows wealth and status as shown below. Which metal is most appropriate for her jewellery?  (1 mark)

After distillation, a student tested the softened water by adding soap flakes and shaking. The water lathered quickly.What is the most likely reason?

After distillation, a student tested the softened water by adding soap flakes and shaking. The water lathered quickly. What is the most likely reason?  (1 mark)

After distillation, a student tested the softened water by adding soap flakes and shaking. The water lathered quickly. What is the most likely reason?  (1 mark)

Scenario: During a science lesson at a school in Eldoret, the teacher asks: "A certain atom has 12 protons. Which metal is this?" Student A quickly says “Aluminium”, while Student B argues “It must be Magnesium”. Who is correct?

During a science lesson at a school in Eldoret, the teacher asks. "A certain atom has 12 protons. Which metal is this?" Student A quickly says “Aluminium”, while Student B argues “It must be Magnesium”. Who is correct? (1 mark)

During a science lesson at a school in Eldoret, the teacher asks. "A certain atom has 12 protons. Which metal is this?" Student A quickly says “Aluminium”, while Student B argues “It must be Magnesium”. Who is correct? (1 mark)

A Kenyan aircraft technician chooses an alloy for aircraft parts that is lightweight but strong. It is composed of aluminium, copper, and other metals. What is the name of this alloy?

A Kenyan aircraft technician chooses an alloy for aircraft parts that is lightweight but strong. It is composed of aluminium, copper, and other metals. What is the name of this alloy? (1 mark)

A Kenyan aircraft technician chooses an alloy for aircraft parts that is lightweight but strong. It is composed of aluminium, copper, and other metals. What is the name of this alloy? (1 mark)

A Kenyan aircraft technician chooses an alloy for aircraft parts that is lightweight but strong. It is composed of aluminium, copper, and other metals. What is the name of this alloy? (1 mark)

A jua kali artisan in Kisumu wants to make a decorative gate. Which property of the metal should he consider most when shaping the metal into patterns?

A jua kali artisan in Kisumu wants to make a decorative gate. Which property of the metal should he consider most when shaping the metal into patterns?  (1 mark)

A jua kali artisan in Kisumu wants to make a decorative gate. Which property of the metal should he consider most when shaping the metal into patterns?  (1 mark)

James uses Helium gas for cooling a scientific device. What is the electron arrangement of Helium?

James uses Helium gas for cooling a scientific device. What is the electron arrangement of Helium? (1 mark)

James uses Helium gas for cooling a scientific device. What is the electron arrangement of Helium? (1 mark)

James uses Helium gas for cooling a scientific device. What is the electron arrangement of Helium? (1 mark)