Question 1:
Ikram needs pure water to prepare a solution. His friend gave him a bottle of water. Suggest a way that he can use to determine whether the water is pure or not.
Answer:
• Boil the water – pure water boils at 100°C.
• Determine the density of the water – density of pure water is 1 g cm–3
(Any other answers are accepted)
Ikram needs pure water to prepare a solution. His friend gave him a bottle of water. Suggest a way that he can use to determine whether the water is pure or not.
Answer:
• Boil the water – pure water boils at 100°C.
• Determine the density of the water – density of pure water is 1 g cm–3
(Any other answers are accepted)
Question 2:
Explain the difference between the movement of water molecules at room temperature and at 0°C.
Answer:
The movement of water molecules at room temperature is faster than the movement of water molecules at 0°C.
This is because high temperature causes the water molecules to gain more energy and move faster than the water molecules at 0°C.
Explain the difference between the movement of water molecules at room temperature and at 0°C.
Answer:
The movement of water molecules at room temperature is faster than the movement of water molecules at 0°C.
This is because high temperature causes the water molecules to gain more energy and move faster than the water molecules at 0°C.
Question 3:
Explain one importance of evaporation of water to the human body.
Answer:
Sweat glands secrete sweat onto the surface of the skin to increase the loss of heat through evaporation. Evaporation of sweat cools the human body.
Explain one importance of evaporation of water to the human body.
Answer:
Sweat glands secrete sweat onto the surface of the skin to increase the loss of heat through evaporation. Evaporation of sweat cools the human body.