Is matter around us pure?

Question 1

WHAT IS THE SCIENTEFIC DEFINITION OF A PURE SUBSTANCE?

Answer 1

1) A PURE SUBSTANCE CONSISNTS OF A SINGLE TYPE OF PARTICLE AND ALL IT’S CONSTITUENT PARTICALS ARE CHEMICALLY IDENTICAL.
2) HAS A FIXED COMPOSITION
3) EXAMPLE: SUGAR, SODIUM CHLORIDE

Question 2

WHAT IS A MIXTURE

Answer 2

1 )A MIXTURE IS MADE UP OF TWO OR MORE PURE SUBSTANCES.
2) IT’S COMPOSITION VARIES
3) EXAMPLE: SOIL AND SOFT DRINKS

Question 3

CAN THE COMPONETS OF MIXTURE BE SEPARATED?

Answer 3

YES, THE COMPONETS OF MIXTURE CAN BE SEPARATED THROUGH PHYSICAL PROCESSES SUCH AS EVAPORATION, FILTERATION ETC

Question 4

CAN A PURE SUBSTANCE BE SEPARATED WITH PHYSICAL PROCESSES

Answer 4

NO A PURE SUBSTANCE CANNOT BE SEPARATED WITH PHYSICAL PROCESSES. IT CAN ONLY BE SEPARATED WITH CHEMICAL PROCESSES. FOR EXAMPLE: ELECTROLYSIS

Question 5

WHAT IS A HOMOGENEOUS MIXTURE?

Answer 5

A MIXTURE WHICH HAS UNIFORM COMPOSITION THROUGHOUT IS KNOWN AS HOMOGENEOUS MIXTURES

Question 6

GIVE TWO EXAMPLES OF HOMOGENOUS MIXTURES

Answer 6

EXAMPLE: SALT DISSOLVED IN WATER AND SUGAR DISSOLVED IN WATER

Question 6

CAN THE COMPOSITION OF A HOMOGENEOUS MIXTURE VARY?

Answer 6

YES THE AMOUNT OF SOLUTE MAY VARY BUT THE MIXTURE REMAINS UNIFORM

Question 7

WHAT IS A HETROGENEOUS MIXTURE?

Answer 7

A MIXTURE WITH NON UNIFORM COMPOSITION AND PHYSICALLY VISIBLE DISTINCT PARTS IS KNOWN AS HETROGENEOUS MIXTURES

Question 8

GIVE TWO EXAMPLES OF A HETROGENOUS MIXTURE

Answer 8

EXAMPLES: OIL AND WATER AND SALT AND SULPHUR

Question 9

WHAT IS A SOLUTION?

Answer 9

A SOLUTION IS A HOMOGENEOUS MIXTURE OF TWO OR MORE SUBSTANCES

Question 10

GIVE TWO EXAMPLES OF SOLUTIONS

Answer 10

LEMONADE AND SODA WATER

Question 11

WHAT ARE THE COMPONENTS OF A SOLUTION?

Answer 11

1) SOLVENT: SUBSTANCE WHICH DISSOLVES THE SOLUTE (EXAMPLE WATER IN LEMONADE)

2)SOLUTE: THE SUBSTANCE WHICH GETS DISSOLVED (EXAMPLE LEMON JUICE IN LEMONADE)

Question 12

WHAT ARE THE PROPERTIES OF A SOULTION

Answer 12

1) HOMOGENOUS MIXTURE ( PARTICLES ARE UNIFORMLY SPEARD)
2) PARTICLE SIZE ( PARTICLES ARE SMALLER THAN 1 NANOMETER AND CANNOT BE SEEN WITH NAKED EYES)
3) PARTICLES ARE VERY SMALL HENCE THEY DON’T SCATTER LIGHT
4) CANNOT BE SEPARATED THROUGH PHYSICAL PROCESSES SUCH AS FILTERATION
5) STABILITY : PARTICLES DON’T SETTLE AT THE BOTTOM WHEN LEFT UNDISTURBED , BASICALLY THE PARTICLE IS STABLE

Question 13

PROPERTIES OF A MIXTURE

Answer 13

1) NO NEW SUBSTANCE IS FORMED
2) CAN BE SEPARATED THROUGH PHYSICAL CHANGE
3) CAN EITHER BE HOMOGENEOUS OR HETROGENOUS
4) CAN EXIST IN ALL THREE STATES OF MATTER
5) COMPOSITION VARIES
6) NO FIXED PROPORTION
7) MIXTURES RETAIN THEIR INDIVIDUAL PHYSICAL PROPERTIES

Question 14

PROPERTIES OF SUSPENTION

Answer 14

1) IT IS A HETROGENEOUS MIXTURE, MEANING IT HAS A NON UNIFORM CONSTITUTION
2) PARTICLES ARE VISIBLE TO THE NAKED EYES
3) IT HAS PHYSICALLY DISTINCT PART
4) IT SCATTERS LIGHT, MEANING THE LIGHT PATH IS VISIBLE
5)CAN BE SEPEPARETED WITH PHYSICAL PROCESSES SUCH AS FILTERATION
6) IF THE SOLUTION IS LEFT UNDISTURBED, PARTICLES WILL SETTLE DOWN , INDICATING THE SOLUTION IS UNSTABLE

Question 15

can a solution be present in all 3 states of matter, if yes give examples.

Answer 15

yes a solution can be present in all 3 states of matter. examples
1) gaseous- air
2)solid- alloy ( brass = zinc +copper)
3)liquid - sugar solution, salt solution , lemonade

Question 16

what are alloys

Answer 16

alloys are a mixture of two or more metal or non mental

Question 17

why is an alloy considered a mixture when it can’t be separated through physical means?

Answer 17

alloys are considered a mixture because
1) no new product is formed
2) the mixture still has the property of it’s consecutive particles
3)it has a variable composition

Question 18

why is the colloidal solution considered a heterogeneous mixture if it is uniformly spread throughout and no distinct particles are visible?

Answer 18

because it scatters light, meaning the path of light is visible when it passes through the solution

Question 19

what is Tyndall effect

Answer 19

the phenomenon where scattering of light takes place through the particles in a suspension or colloidal solution is known as Tyndall effect

Question 20

where is the Tyndall effect seen

Answer 20

1)sunlight entering a dark room
2) milk
3)fog

Question 20

what are the properties of a Collidal solution

Answer 20

1) particles cannot be seen
2) it is quite stable
3) it does scatter light
4)particles are uniformly spread

Question 20

what are the two divisions of pure substance

Answer 20

elements & minerals

Question 21

what are elements

Answer 21

element is a form of matter that cannot be broken down into simpler substances by chemical reactions.

Question 22

who was the first scientist to use the term elements?

Answer 22

Robert Boyle (1661)

Question 23

after which scientist is the Tyndall effect named after

Answer 23

John Tyndall

Question 24

who defined the term element

Answer 24

Antoine Laurent Lavoisier

Question 25

properties of metals

Answer 25

1) they has luster 2) they are ductile 3) they are malleable 4) they are sonorous 5) they are good conductors of heat 6) they have a silvery-grey or golden-yellowish color

Question 26

examples of metal

Answer 26

gold, silver etc

Question 27

example of metal which are liquid at room temperature

Answer 27

mercury, bromine

Question 28

example of metals which are liquid slightly above room temperature

Answer 28

gallium, cesium (303K)

Question 29

properties of non metals

Answer 29

1) they have various color 2) bad conductor of heat 3) they are not ductile, malleable, sonorous

Question 30

example of non metal

Answer 30

nitrogen, oxygen, carbon

Question 31

what are metalloids

Answer 31

metalloids are elements which have properties of both metals and non metals

Question 32

example of metalloids

Answer 32

boron, silicon and germanium

Question 33

how many elements are gaseous at room temperature

Answer 33

11

Question 34

what is a compound

Answer 34

a compound is a substance composed of two or more elements chemically combined in a fixed proportion

Question 35

properties of a compound

Answer 35

1) fixed composition 2) doesnt have properties of the constituent particles 3)can only be separated through chemical processes

Question 36

examples of compound

Answer 36

water, carbon dioxide

Question 37

depending upon the amount of solute present in a given solution the solution can be_________, __________ or___________.

Answer 37

1) dilute 2) concentrated 3) saturated

Question 38

meaning of a dilute solution

Answer 38

a solution which has move amount of solvent than solute

Question 39

meaning of a concentrated solution

Answer 39

a solution which has large amount of solute compared to solvent

Question 40

meaning of saturated solution

Answer 40

when no more solute can be dissolved in the solution in a given temperature the solution is said to be saturated

Question 41

meaning of unsaturated solution

Answer 41

an unsaturated solution is a solution in which more solute can be dissolved at a given temperature, in other words the solution hasn't reached it's saturation level

Question 42

define solubility

Answer 42

the amount of solute present in the saturated solution at a given temperature is called it's solubility

Question 43

properties of physical change

Answer 43

1) no new substance is formed 2) can be reversed 3) change of state of matter

Question 44

properties of chemical change

Answer 44

1) new substance is formed 2) cannot be reversed 3) boiling, digestion of food, rusting of iron