matter

Question 1

matter

Answer 1

its anything has mass and volume

Question 2

mass

Answer 2

it is the amount of matter that body contains

Question 3

volumei

Answer 3

it is the space that is occupied by the body

Question 4

physical properties

Answer 4

the color taste smell
density
melting point
boiling point
hardness
electric conduction
thermal conduction

Question 5

the color taste smell

Answer 5

color: silver gold iron
taste: table salt sugar flour
smell: vinegar perfume

Question 6

density

Answer 6

it is the mass of the unit volume of the substance
d =m+v the measuring unit is gm/cm3

Question 7

what is meant by the density of water equal 1gm/cm2

Answer 7

this means the mass of 1cm3 of water equals 1 gm

Question 8

equal masses of different substances have different volumes

Answer 8

due to the difference in the density

Question 9

v2-v1=v m2-m1= m

Answer 9

d =m- v v = m-d m= d+v

Question 10

water is not used to put out petrol fires

Answer 10

b.c the density of petrol is less than the density of water so the fire float on the water surface

Question 11

balloons filled with hydrogen or helium rise at festivals

Answer 11

b.c the density of hydrogen and helium are less than the density of air

Question 12

melting point

Answer 12

It’s the temperature at which the matter begins to change from solid-state to liquid-state 0
low wax butter ice
high iron copper table salt aluminum

Question 13

BOILING point

Answer 13

It’s the temperature at which the matter begins to change from liquid -state to gases-state 100

Question 14

pots are made up from aluminium

Answer 14

due to their high melting point

Question 15

workmen melt the solid metals

Answer 15

to be easy to mix and shape to form the alloy
copper gold nickel chrome
making jewels making heating coils

Question 16

the separation of the components of crude petroleum oil by heating

Answer 16

due to their differences between their boiling points

Question 17

hardness

Answer 17

soft in the room ordinary temperature
become soft by heating metals
cannot be softened by heating coal & sulphur

Question 18

the screwdrivers are made up of steel iron

Answer 18

b.c its very hard

Question 19

the rods are made up of iron not copper

Answer 19

b.c the iron hardness is more than the copper hardness

Question 20

electric conduction

Answer 20

good some salt solutions /alkaline /acidic and metals
bad sugary solutions and hydrogen chloride in benzene and gases and sulphur phosphorus wood plastic

Question 21

electric screwdrivers are made up of steel iron while their handles are from plastic

Answer 21

b.c the steel iron is a good conductor of electricity while plastic is a bad conductor of electricity

Question 22

thermal conduction

Answer 22

good metals
bad wood and plastic

Question 23

cooking pans are made up of aluminum

Answer 23

aluminium is good conductor of heat and has a high melting point

Question 23

very active metals

Answer 23

they react with oxygen when they exposed to humid air so they lose luster
sodium and potassium

Question 24

they are left under kerosine

Answer 24

to prevent their reaction with atmospheric air

Question 25

less active metals

Answer 25

they react with the oxygen if they are left in the air for some days forming a rust layer
metals

Question 26

steel bridges are painted from time to time

Answer 26

to protect them from rust

Question 27

pots are washed with rough surface

Answer 27

to remove the rust layer formed on their surfaces

Question 28

inactive metals

Answer 28

they are metal which finds difficult to react with oxygen
silver platinum nickel gold chromium

Question 29

silver gold platinum are used in making jewels

Answer 29

they are chemically poor active so they keep their luster for a long time

Question 30

nickel gold silver are used to cover other substances which rabidly gain rust as iron

Answer 30

to protect them from rust and corrosion