Extra sheet

Questions on unit 1

Lesson (1)

I. Complete the following statements:

  1. Matter is anything that has mass and volume.
  2. You can distinguish between gold and silver by their different color.
  3. You can differentiate between table salt and sugar by their differenttaste.
  4. It is possible to distinguish between perfume and vinegar by their differentsmell.
  5. Gmis the measuring unit of mass, whilecm3 is the measuring unit of volume.
  6. The density is themassof unit volume of a substance its measuring unit isgm/cm3
  7. Equal volumes of different substances have different masses as they differ in theirdensities.
  8. Cork and wood float on water surface at they have lowerdensity than that of water
  9. Ironandcoinsink in water as they have higher density than that of water.
  10. The mass of one cubic centimeter of a matter is known asdensity.
  11. Density = massvolume
  12. The temperature at which the solid substance changes in to liquid is calledmelting point .
  13. Boiling pointis the temperature at which the liquid substance changes into gas.
  14. ice and wax are from the substances which have low melting point, while iron andcopperare from the substances which have high melting point.

15 .copper – goldalloy is used in making jewels, while nickel –chromealloy is used in making heating coils.
16.Iron and copper are good conductors of electricity and heat, while wood and plasticare bad conductors of electricity and heat
17. Electric wires are made ofcopper or aluminum as they are goodconductors of electricity.
18. Steel bridges and the holders of light bulbs are painted from time to time to be protected from rust and corrosion.

II. Choose the correct answer:-

  1. Matter is anything that has …….

a. Mass only. b.mass and length

c. volume only d. mass and volume

  1. The colour property is a distinguishing factor between…………

a. table salt and flour. b. iron and gold. c. oxygen and nitrogen d. oxygen and carbon dioxide

  1. the taste property is a distinguishing factor between……….

a. milk and honey b. wood and plastic

c. silver and gold d. oxygen and nitrogen

  1. The smell property is a distinguishing factor between……

a. iron and copper b. vinegar and perfume c. wood and plastic d. silver and iron

  1. The measuring unit of density is …………………

a. gm/cm. b. gm/cm2

c. gm/m3. d. gm/cm3

6. Heating coils are made of ...... alloy.
a. iron and copper b. nickel and iron c. nickel and chrome d. chrome and copper

7. Separation of petroleum components depends on the difference in their ......

a. melting points. b. density c. boiling points. d. all of them.
8. The property of electrical conductivity is a distinguishing factor between ......
a. iron and copper. b. wood and plastic c. iron and wood. d. no correct answer
9...... are very active metals which react with oxygen when they are exposed to
moist air.
a. Sodium and iron b. Copper and aluminium
c. Sodium and potassium d. Silver and gold
10. The balloons are filled with helium gas in celebrations, then they rise up in air, because

a. density of helium is more than that of air.

b. density of helium equals that of air.

c. density of helium is less than that of air.

III. Write the scientific term for each of the following:

1. Anything that has a mass and a volume. ( matter )

2. The mass of unit volume of the substance. ( density )

3. The temperature at which a substance changes from the solid state to the liquid state. ( Melting point)

4. The temperature at which the substance changes from the liquid state to the gaseous state. (Boiling point )

5. The measuring unit of density. ( gm/cm3)

6. The mass of one cubic centimeter of a substance. (density )

7. Anything that occupies a space and has a mass. (volume )

8. An alloy used in the manufacture of heating coils. (nickel-chrome)

9. An alloy used in making gold objects. (copper-gold)

IV. Give reason for each of the following:

  1. A piece of wood floats on the water surface while a piece of lead sinks in it.

* because wood has lower density than water but lead has higher density than water.

2. Equal volumes of different substances have different masses.

* because they have different denisties.

3. Petrol fires are not put out by water.

* because the density of the petrol oil is lower than the density of water.

4. Balloons which are full of hydrogen or helium rise up in the air.

* because hydrogen and helium have lower density than the density of air.

5. Cooking pans are made of aluminum and stainless steel.

*because aluminum and stainless steel have high melting point and they are good conductors of heat.

6. Apiece of ice melts when it is left in the air.

* because ice has low melting point.

7. Aluminum and copper are used in making electric wires.

* because aluminum and copper are good conductor of electricity .

8. Handles of cooking pans are made of wood or plastic.

*because wood and plastic are bad conductors of heat.

9. An electrician uses a steel screwdriver with a plastic handle.

*because steel is very hard and good conductor of electricity but plastic is bad conductor of electricity.

10. Hardness can be used to distinguish between rubber and gold.

Because rubber is soft at room temperature but gold can be soft by heating.

V. Mention an example for the substance that:

1. appears soft at room temperature. rubber

2. Is used in making electric wires. Copper and aluminum

3. Doesn’t conduct heat and electricity. Wood and plastic

VI. What is meant by each of the following:

  1. Matter.

Anything that has mass and volume

  1. Density.

The mass of unit volume of substance.

The mass of 1 cm3 of substance.

  1. The density of iron is 7.8 gm/cm3

The mass of unit volume of iron is 7.8gm/cm3

  1. Melting point.

The temperature at which the matter begins to change from solid state to liquid state.

  1. Boiling point.

The temperature at which the matter begins to change from liquid state to gas state.

VII. Problems:-

  1. If the density of alcohol is 0.8 gm/cm3.,find the volume of 80 grams of it.

M

Volume = mass = 80 =100 cm3

Density 0.8DV

  1. In an experiment to determine the density of a piece of rock, the following results were recorded:
  2. the volume of water in the cylinder= 80 cm3.
  3. The volume of water and the rock = 120 cm3
  4. The mass of the piece of rock = 20 gms.

Calculate the density of the rock.

V1=80 cm3 V2=120 cm3

The volume of the rock= V2-V1=120-80=40 cm3

The density= mass = 20 = 0.5 gm/cm3

Volume 40

  1. Calculate the mass of 1000 cm3 of milk knowing that its density is 1.03 gm/cm3.

The mass = density x volume = 1000 x 1.03 = 1030 gm

  1. Calculate the volume of 500 gm of iron if its density is 7.8 gm/cm3.

The volume = mass = 500 = 64.1 cm3

Density 7.8

  1. A piece of iron is put in a beaker contains 100 cm3 of water the volume becomes 150 cm3 if the mass of this piece is 390 gm, calculate the density if the iron.

V1= 100 cm3 V2= 150 cm3

The volume of iron= V2-V1= 150-100=50 Cm3

Density = mass = 390 = 7.8 gm/cm3

Volume 50

6.At which graduation water rises, when a piece of aluminum its mass is 27 gm is immersed in a graduated cylinder containing 100 cm3 of water. Knowing that the density is 2.7 gm/cm3.

V1=100 V2=? Mass=27 gm density=2.7 gm /cm3

The volume of aluminum= mass = 27 = 10 cm3

Density 2.7

The volume of water and aluminum= V1+V2=100+10=110 cm3

VIII. The following figures represent four balls which are similar in volume, massand type. They are put it four beakers containing different liquids.

Answer the following questions:

  1. Arrange the four liquids in an ascending order according to their densities'.

A-C-D-B

2. In which figure the density of the ball is:

A. greater than that of the liquid. B

B. less than that of the liquid. A&C

C. equal to that of the liquid.. D