.
Give reasons for
1-Air is matter.
Because it has a mass and volume.
2. The car has a volume.
Because it occupies a certain space.
.
3. When some pieàes of stone are put in a glass full of water
an amount of water is spilled out of the glass.
Because the volume of the pieces of stone equal the volume of the spilled water.
4. Gold and copper are solids.
Because they have definite shapes and volumes. .
5. Air is a gaseous matter.
Because it hasn’t a definite shape or volume.
6. Milk is a liquid matter.
Because it has a definite volume, but doesn’t have a definite shape.
7. Wood has a definite shape and volume.
Because wood is a solid matter.
8. Oxygen has an indefinite shape and volume.
Because oxygen is a gaseous matter.
9. Ice changes into water if a beaker of ice is exposed to air.
Because heat from the air cause melting ice and changes into water.
10. On making tea, water drops are formed on the cover of the teapot from Inside.
Due to the condensation of water vapour on the cover of the teapot.
11. Water freezes when it is put in the freezer.
Because water changes into ice by cooing.
12. The washed clothes become dry after exposing them to the heat of the atmosphere.
Because the water in the clothes evaporates and changes into water vapour by the effect of heat
13. Gaseous matter is compressed and packed in cylinders.
Because gaseous matter takes the shape and volume of its container.
14. A piece of copper has a definite shape
Because copper is a solid matter.
15. The glass bottle which is put in the freezer shouldn’t be full of water.
Because when water changes into ice, the volume of ice is bigger than the volume of water, so the bottle will explode.
16. Sulphur is an element.
Because it can’t be analyzed into two substances or more.
17. Iron and copper are metals.
Because:
— They are shiny., They can be bent or hammered.
— They have high melting and boiling points.
— They are good conductors of heat an electricity.
18. Sulphur is considered as a non-metal.
Because: -
— It is not shiny, it can’t be bent or hammered.
— It has low melting and boiling points.
— It is a bad conductor of heat and electricity.
19. Gold and silver are used in making jewellery.
Because they can be bent or re-shaped as they are metals.
. 20. Copper is used in the manufacture of electric wires.
Because copper is a good conductor of electricity
21. Aluminium can be bent or hammered, but a piece of coal (carbon) can’t be.
Because aluminium is a metal, but coal (carbon) is non-metal.
22. Cooking pans are made up of alumInium.
Because aluminium is a good conductor of heat.
23. Handles of cooking pots are made of wood or plastic.
Because wood and plastic are bad conductors of heat.
24. Carbon is a non-metal although it is used in making the positive electrode of the dry cell.
Because it is a good conductor of electricity.
25. Aluminium is considered as a metal, but bromine is a non-metal.
Because aluminium is shiny, can be bent or hammered, has high melting and boiling points and is a good conductor of heat and electricity, but bromine is not.
26. We musn’t approach a nail to an. electric source.
Because the nail is made up of iron which conducts electricity as it is a metal.
27. The melting point of an Iron nail is higher than that of Sulphur crystals.
Because iron is a metal, but Sulphur is a non-metal.
28. Copper is used in making statues and metallic coins.
Because copper can be bent or hammered to form sheets as it is a metal.
29. Car chassis, doors and bridges are made up of metals not of nonmetals.
Because metals cane bent or hammered to form sheets, but non- metals can’t .
30. The electrician stands on a wooden chair when he makes some electrical repairs.
Because wood is a bad conductor of electricity.
31. Iron is used in making lamp posts.
Because it can be bent or hammered .
32. Melting of ice is a physical change.
Because melting of ice causes a hare in the shape of wax without
any change in its structure.
33- Melting of wax is a physical change.
Because melting of wax causes a chang.p in the shap€ of wax
without any change in its structure.
34. The change of water 1nto 1ce is a physical change.
Because the shape of water changes, but its structure doesn’t change.
35 . Burning a piece of paper is a chemical change.
Because this causes a change in the shape and structure of paper
producing a new substance with new properties.
36. Formation of a layer of rust on the surface of wet iron wire.
Due to the reaction between iron and both water and oxygen producing a new substance with new properties as this is a chemical change.
37. Sugar keeps its flavour after dissolving it in water.
Because dissolving sugar in water is a physical change,.
38. A black substance is produced after burning a piece of paper.
Because..burning a piece of paper is a chemical change as the shape and structure of paper change
39. Formation of clouds and rain is a physical change.
Because clouds and rain are changes in the shape of water without any change in its structure.
Give reasons for
1-Air is matter.
Because it has a mass and volume.
2. The car has a volume.
Because it occupies a certain space.
.
3. When some pieàes of stone are put in a glass full of water
an amount of water is spilled out of the glass.
Because the volume of the pieces of stone equal the volume of the spilled water.
4. Gold and copper are solids.
Because they have definite shapes and volumes. .
5. Air is a gaseous matter.
Because it hasn’t a definite shape or volume.
6. Milk is a liquid matter.
Because it has a definite volume, but doesn’t have a definite shape.
7. Wood has a definite shape and volume.
Because wood is a solid matter.
8. Oxygen has an indefinite shape and volume.
Because oxygen is a gaseous matter.
9. Ice changes into water if a beaker of ice is exposed to air.
Because heat from the air cause melting ice and changes into water.
10. On making tea, water drops are formed on the cover of the teapot from Inside.
Due to the condensation of water vapour on the cover of the teapot.
11. Water freezes when it is put in the freezer.
Because water changes into ice by cooing.
12. The washed clothes become dry after exposing them to the heat of the atmosphere.
Because the water in the clothes evaporates and changes into water vapour by the effect of heat
13. Gaseous matter is compressed and packed in cylinders.
Because gaseous matter takes the shape and volume of its container.
14. A piece of copper has a definite shape
Because copper is a solid matter.
15. The glass bottle which is put in the freezer shouldn’t be full of water.
Because when water changes into ice, the volume of ice is bigger than the volume of water, so the bottle will explode.
16. Sulphur is an element.
Because it can’t be analyzed into two substances or more.
17. Iron and copper are metals.
Because:
— They are shiny., They can be bent or hammered.
— They have high melting and boiling points.
— They are good conductors of heat an electricity.
18. Sulphur is considered as a non-metal.
Because: -
— It is not shiny, it can’t be bent or hammered.
— It has low melting and boiling points.
— It is a bad conductor of heat and electricity.
19. Gold and silver are used in making jewellery.
Because they can be bent or re-shaped as they are metals.
. 20. Copper is used in the manufacture of electric wires.
Because copper is a good conductor of electricity
21. Aluminium can be bent or hammered, but a piece of coal (carbon) can’t be.
Because aluminium is a metal, but coal (carbon) is non-metal.
22. Cooking pans are made up of alumInium.
Because aluminium is a good conductor of heat.
23. Handles of cooking pots are made of wood or plastic.
Because wood and plastic are bad conductors of heat.
24. Carbon is a non-metal although it is used in making the positive electrode of the dry cell.
Because it is a good conductor of electricity.
25. Aluminium is considered as a metal, but bromine is a non-metal.
Because aluminium is shiny, can be bent or hammered, has high melting and boiling points and is a good conductor of heat and electricity, but bromine is not.
26. We musn’t approach a nail to an. electric source.
Because the nail is made up of iron which conducts electricity as it is a metal.
27. The melting point of an Iron nail is higher than that of Sulphur crystals.
Because iron is a metal, but Sulphur is a non-metal.
28. Copper is used in making statues and metallic coins.
Because copper can be bent or hammered to form sheets as it is a metal.
29. Car chassis, doors and bridges are made up of metals not of nonmetals.
Because metals cane bent or hammered to form sheets, but non- metals can’t .
30. The electrician stands on a wooden chair when he makes some electrical repairs.
Because wood is a bad conductor of electricity.
31. Iron is used in making lamp posts.
Because it can be bent or hammered .
32. Melting of ice is a physical change.
Because melting of ice causes a hare in the shape of wax without
any change in its structure.
33- Melting of wax is a physical change.
Because melting of wax causes a chang.p in the shap€ of wax
without any change in its structure.
34. The change of water 1nto 1ce is a physical change.
Because the shape of water changes, but its structure doesn’t change.
35 . Burning a piece of paper is a chemical change.
Because this causes a change in the shape and structure of paper
producing a new substance with new properties.
36. Formation of a layer of rust on the surface of wet iron wire.
Due to the reaction between iron and both water and oxygen producing a new substance with new properties as this is a chemical change.
37. Sugar keeps its flavour after dissolving it in water.
Because dissolving sugar in water is a physical change,.
38. A black substance is produced after burning a piece of paper.
Because..burning a piece of paper is a chemical change as the shape and structure of paper change
39. Formation of clouds and rain is a physical change.
Because clouds and rain are changes in the shape of water without any change in its structure.
