Mixtures, Elements and Compounds practice exercise 1

In a local clinic, a doctor orders a test to measure Phosphorus in a patient’s blood. Lab results show atoms with 15 protons and 16 neutrons. Calculate the mass number and explain why the mass number must be correct for interpreting patient health. (2 marks)

In a local clinic, a doctor orders a test to measure Phosphorus in a patient’s blood. Lab results show atoms with 15 protons and 16 neutrons. Calculate the mass number and explain why the mass number must be correct for interpreting patient health. (2 marks)

A doctor at a local clinic orders a test to measure phosphorus levels in a patient's blood. The lab results indicate that the most abundant phosphorus atoms present have 15 protons and 16 neutrons.a) Calculate the mass number of these phosphorus atoms. (1 mark)b) Explain why the mass number of a specific isotope is generally not a factor in interpreting the health of a patient based on a standard blood test. (1 mark)

The diagram below shows the electron configuration of calcium and neon. Classify each as a metal or non-metal and explain your reasoning. (2 marks)  

The diagram below shows the electron configuration of calcium and neon. Classify each as a metal or non-metal and explain your reasoning. (2 marks)  

The diagram below shows the electron configuration of calcium and neon. Classify each as a metal or non-metal and explain your reasoning. (2 marks)  

A school electrician in Mombasa is replacing wires in the science lab. What two physical properties of copper make it suitable for wiring, and why are they important?  (2 marks)

A school electrician in Mombasa is replacing wires in the science lab. What two physical properties of copper make it suitable for wiring, and why are they important?  (2 marks)

Kenya Airways considers replacing heavy steel parts with another alloy, shown in the image below, to reduce fuel use while keeping safety. Name the alloy, give its composition, and explain why it is better. (2 marks)

Kenya Airways considers replacing heavy steel parts with another alloy, shown in the image below, to reduce fuel use while keeping safety. Name the alloy, give its composition, and explain why it is better. (2 marks)

Kenya Airways considers replacing heavy steel parts with another alloy, shown in the image below, to reduce fuel use while keeping safety. Name the alloy, give its composition, and explain why it is better. (2 marks)

In a school project, learners work with Calcium, which has 20 protons and 20 neutrons.(a) What is the electron arrangement of Calcium? (1 mark)(b) Draw a dot  diagram. (1 mark)(c) Calculate its mass number. (1 mark)(d) Why is knowing Calcium’s electron arrangement important in science learning? (1 mark)

In a school project, learners work with Calcium, which has 20 protons and 20 neutrons.(a) What is the electron arrangement of Calcium? (1 mark)(b) Draw a dot  diagram. (1 mark)(c) Calculate its mass number. (1 mark)(d) Why is knowing Calcium’s electron arrangement important in science learning? (1 mark)

In a school project, learners work with Calcium, which has 20 protons and 20 neutrons.(a) What is the electron arrangement of Calcium? (1 mark)(b) Draw a dot diagram to show its electron configuration. (1 mark)(c) Calculate its mass number. (1 mark)(d) Why is knowing Calcium’s electron arrangement important in science learning? (1 mark)

A hospital in Nairobi is seeking bids for medical implants like hip and knee replacements. Two suppliers propose items made from aluminium alloys and titanium alloys. Which should the hospital choose and why?  (1 mark)

A hospital in Nairobi is seeking bids for medical implants like hip and knee replacements. Two suppliers propose items made from aluminium alloys and titanium alloys. Which should the hospital choose and why?  (1 mark)

A hospital in Nairobi is seeking bids for medical implants like hip and knee replacements. Two suppliers propose items made from aluminium alloys and titanium alloys. Which should the hospital choose and why?  (1 mark)

A boarding school uses two water tanks. Water from Tank A forms foam easily, while water from Tank B forms scum and poor lather. The image below shows water samples after shaking with soap. Which tank has hard water and what should the school do?

A boarding school uses two water tanks. Water from Tank A forms foam easily, while water from Tank B forms scum and poor lather. The image below shows water samples after shaking with soap. Which tank has hard water and what should the school do?

A boarding school uses two water tanks. Water from Tank A forms foam easily, while water from Tank B forms scum and poor lather. The image below shows water samples after shaking with soap. Which tank has hard water and what should the school do? (2 marks)

In a rural village, women complain that ugali takes unusually long to cook when using well water. What explains this?

In a rural village, women complain that ugali takes unusually long to cook when using well water. What explains this?  (1 mark)

In a rural village, women complain that ugali takes unusually long to cook when using well water. What explains this?  (1 mark)

A family notices white deposits at the bottom of their kettle after boiling water multiple times. What should they suspect?

A family notices white deposits at the bottom of their kettle after boiling water multiple times. What should they suspect? (1 mark)

A family notices white deposits at the bottom of their kettle after boiling water multiple times. What should they suspect? (1 mark)

A family notices white deposits at the bottom of their kettle after boiling water multiple times. What should they suspect? (1 mark)

A nutritionist in Kisumu advises a patient with high blood pressure to avoid drinking softened water. What is the main reason for this advice?

A nutritionist in Kisumu advises a patient with high blood pressure to avoid drinking softened water. What is the main reason for this advice?  (1 mark)

A nutritionist in Kisumu advises a patient with high blood pressure to avoid drinking softened water. What is the main reason for this advice?  (1 mark)

A student wants to soften hard borehole water containing both calcium bicarbonate and magnesium sulphate. Which method will remove both types of hardness effectively?

A student wants to soften hard borehole water containing both calcium bicarbonate and magnesium sulphate. Which method will remove both types of hardness effectively?  (1 mark)

A student wants to soften hard borehole water containing both calcium bicarbonate and magnesium sulphate. Which method will remove both types of hardness effectively?  (1 mark)

A farmer in Kisumu notices that his wheelbarrow starts rusting quickly during the rainy season. Which method would be the most effective in protecting the wheelbarrow from rust?

A farmer in Kisumu notices that his wheelbarrow starts rusting quickly during the rainy season. Which method would be the most effective in protecting the wheelbarrow from rust?  (1 mark)

A farmer in Kisumu notices that his wheelbarrow starts rusting quickly during the rainy season. Which method would be the most effective in protecting the wheelbarrow from rust?  (1 mark)

A salon owner in Kisii reports that her shampoo does not foam quickly when washing clients’ hair. A technician tests the water and recommends using soft water. Why was this advice helpful?

A salon owner in Kisii reports that her shampoo does not foam quickly when washing clients’ hair. A technician tests the water and recommends using soft water. Why was this advice helpful?  (1 mark)

A salon owner in Kisii reports that her shampoo does not foam quickly when washing clients’ hair. A technician tests the water and recommends using soft water. Why was this advice helpful?  (1 mark)

Contest board diagram: Nucleus: 12 protons, 12 neutrons Electrons in shells: 2 in first, 8 in second, 2 in third Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!” Who is right? A. Student A is correct – Sodium B. Student B is correct – Magnesium C. Both are correct D. Neither is correct

  In a science contest, a learner drew the atom below on the board. Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!”. Who was correct between the two? (1 mark)

In a science contest, a learner drew the atom below on the board. Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!”. Who was correct between the two? (1 mark)

In a science contest, a learner drew the atom below on the board. Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!”. Who was correct between the two? (1 mark)

In a science contest, a learner drew the atom below on the board. Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!”. Who was correct between the two? (1 mark)

In a science contest, a learner drew the atom below on the board. Student A shouted: “This is Sodium!” Student B disagreed: “No, it’s Magnesium!”. Who was correct between the two? (1 mark)

A plumber is choosing a metal to use in fittings for a water purification system in Kisii. The fittings must last long and not rust, even when exposed to damp conditions. Which metal is the best option?

A plumber is choosing a metal to use in fittings for a water purification system in Kisii. The fittings must last long and not rust, even when exposed to damp conditions. Which metal is the best option?  (1 mark)

A plumber is choosing a metal to use in fittings for a water purification system in Kisii. The fittings must last long and not rust, even when exposed to damp conditions. Which metal is the best option?  (1 mark)

A plumber is choosing a metal to use in fittings for a water purification system in Ktui. The fittings must last long and not rust, even when exposed to damp conditions. Which metal is the best option?  (1 mark)