Gujarat Board GSEB Textbook Solutions Class 8 Science Chapter 4 Materials: Metals and Non-Metals Textbook Questions and Answers, Notes Pdf.
Gujarat Board Textbook Solutions Class 8 Science Chapter 4 Materials: Metals and Non-Metals
Gujarat Board Class 8 Science Materials: Metals and Non-Metals Textbook Questions and Answers
Question 1.
Which of the following can be beaten into thin sheets?
(a) Zinc
(b) Phosphorus
(c) Sulphur
(d) Oxygen
Answer:
(a) Zinc.
Question 2.
Which of the following statements is correct?
(а) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
Answer:
(c) Generally metals are ductile.
Question 3.
Fill in the blanks.
(a) Phosphorus is a very ________ non-metal.
(b) Metals are ________ conductors of heat and
(c) Iron is ________ reactive than copper.
(d) Metals react with acids to produce ________ gas.
Answer:
(a) reactive
(b) good, electricity
(c) more
(d) hydrogen
Question 4.
Mark ‘T’ if the statement is true and ‘F’ if it is false.
(a) Generally, non-metals react with acids.
(b) Sodium is a very reactive metal.
(c) Copper displaces zinc from zinc sulphate solution.
(d) Coal can be drawn into wires.
Answer:
(a) False
(b) True
(c) False
(d) False
Question 5.
Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties.
Answer:
Question 6.
Give reasons for the following.
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Answer:
(a) Aluminium is malleable, soft and does not react with food items, so it is used to wrap food items.
(b) Metals are good conductor of heat and electricity, so immersion rods are made up of metallic substances.
(c) Copper is less reactive than zinc, so it cannot displace zinc from its salt solution.
(d) Sodium and potassium are very reactive; they react with air and water. So they are stored in kerosene.
Question 7.
Can you store lemon pickle in an aluminium utensil? Explain.
Answer:
No, we cannot store the lemon pickle in aluminium utensil because aluminium is a metal and lemon is acidic. Acids react with metals to give hydrogen gas which would spoil the food and make it unfit for use.
Question 8.
Match the substances given in Column A with their uses given in Column B.
Answer:
Question 9.
What happens when
(a) Dilute sulphuric acid is poured on a copper plate?
(b) Iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.
Answer:
(a) When dilute sulphuric acid is poured on a copper plate, copper reacts with acid to give copper sulphate and hydrogen gas.
Sulphuric acid + Copper → Copper sulphate + Hydrogen
(b) When iron nails are placed in copper sulphate solution, displacement reaction takes place in which iron displaces copper.
Copper sulphate + Iron → Iron sulphate + Copper The blue colour turns into green.
Question 10.
Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(a) How will she find the nature of the gas?
(b) Write down word equations of all the reactions taking place in this process.
Answer:
(a) When charcoal is burnt, carbon dioxide gas is formed. This gas turns lime water milky. It can also be tested by red and blue litmus. The solution of gas turns blue litmus into red, so it is acidic.
(b) Carbon + Oxygen → Carbon dioxide
Carbon dioxide + Lime water → Milky
Question 11.
One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
Answer:
Gold is a metal which is washed in acidic solution. Some gold dissolves in acid to form oxide. This causes the loss of gold in the form of gold oxide. In this process, certain amount of gold is lost to the acidic solution.