Page 49 - ICSE Chemistry 6

C. Choose the correct op on.
1. Silicon and arsenic are ____________.
(a) metals (b) non-metals (c) metalloids (d) noble gases
2. Noble gases are present only in traces in ____________.
(a) air (b) earth’s crust (c) oceans (d) all of these
3. The symbol of lead is _________.
(a) Pb (b) L (c) Le (d) Pl
4. Which of these cannot be separated by fi ltra on?
(a) A mixture of chalk powder and water (b) A mixture of sand and water
(c) A mixture of sugar and milk (d) A mixture of rice and milk
5. The insoluble solid le behind on the fi lter paper during fi ltra on is called ___________.
(a) fi ltrate (b) par cle (c) residue (d) sediment

6. Which of the following can be used in addi on to fi lter paper in the process of fi ltra on?
(a) Glass wool (b) Unglazed porcelain (c) Co on (d) All of these

D. Match the columns.
Column A Column B
1. Gold and silver (a) Non-metals
2. Phosphorus (b) Smallest unit of an element
3. Boron and an mony (c) Mixture

4. Milk (d) Metals
5. Atom (e) Remove pulp from fresh juice
6. Filtra on (f) Metalloid

SHORT AND PRECISE
A. Show the given text in the form of fl owcharts.

1. Elements classifi ed as metals, non-metals and metalloids
2. Methods of separa on of mixtures

B. Give reasons for the following statements.
1. An element is a pure substance.
2. The composi on of water remains the same whether it is obtained from river, pond, sea or ocean.
3. The atoms exist in combina on with the atoms of same element or other elements.
4. Copper is used to make electrical wires.

5. Plas c is used to insulate wires.
6. Carbon dioxide is used in fi re ex nguishers.
7. Mixtures are impure substances.
8. A mixture is heated in the process of evapora on.

C. Write the molecular formulae of the following compounds.
1. Carbon dioxide 2. Magnesium oxide 3. Zinc chloride
4. Calcium oxide 5. Water 6. Copper oxide

35