|
General properties of Metals & Non Metals |
Metals are Solid, Hard, Good conductors of heat and
electricity, Lustrous, Malleable, Ductile & sonorous. Non metals have
opposite properties |
|
Exceptions to the above properties |
Metals are solid except Mercury, Non metals are non
lustrous except Iodine, Non metals soft except Carbon (Diamond) which is
hardest material on earth, Alkali metals very soft like butter |
|
Chemical Properties of Metals |
Metals react with air to form oxides which are basic in
nature. Metals react with water to form metal oxide and
hydrogen Metals react with acid to form Salt and Hydrogen Metals Displace other metals from their salts based on
reactivity series Metals react with Non metals to form Ionic compounds |
|
Steps in Metallurgy |
Step 1: Extraction of Ores Step: Enrichment of Ore Step 3: Extraction of Metal from Ore Step 4: Refining of Metals |
|
Prevention of Corrosion |
Painting, Oiling, Greasing, Galvanizing, Chrome
Plating, Anodizing & Alloying |
|
Examples of Alloys |
Brass (Copper + Zinc) Bronze (Copper + Tin) Nichrome (Nickel + Chromium) Manganin (Copper + Manganese etc.) Amalgam (Any Metal + Mercury) Solder (Lead + Tin) Stainless steel (Iron + Chromium + Carbon etc.) |
|
Reactivity Series |
Potassium > Sodium > Calcium > Magnesium > Aluminum > Zinc > Iron > Lead > Hydrogen > Copper >
Mercury > Silver > Gold |
Q. Explain
the different physical properties of metals?
Ans: Following are different physical properties of metals;
Metals are solids, except Mercury (Hg),
They are hard, Except Sodium (Na), Potassium (K)
They have lustre and are malleable and ductile.
They are also good conductors of electricity with high melting and boiling
points.
Q. Differentiate between metals and non-metals on basis of chemical
properties?
Ans:
|
Metals |
Non-Metals |
|
The metals
form basic oxides |
Nonmetals form
acidic or neutral oxides |
|
Metals
displace hydrogen from dilute acids |
non-metals
don’t displace hydrogen from dilute acids. |
|
Metals don't react
with hydrogen |
Non-metals
react with hydrogen |
|
Metals form
Ionic bond with Chlorine |
Non-Metals
form Covalent bond with Chlorine |
Q. Define metallurgy. Describe the various methods of concentration of Ore?
Ans: Metallurgy is the process of extracting metals from their ores.
It involves concentration of ore, extraction of metal from concentrated ore and
purification of impure metal.
Concentration of ore: Concentration of Ore means removal of
impurities like sand, clay, rocky material and increasing quantity of ore. Following
methods are used:
1. Hydraulic washing: It separates ore from impurities on
basis of density. The lighter impurities wash away and ore, which is heavy,
settles down.
2. Froth Floatation: When ore is lighter than its impurities,
the ore is mixed with small quantities of oil and air is blown in
the tank. This leads to the formation of froth. The heavy impurities settle
down and are removed.
3. Magnetic separation
4. Leaching etc.
Q. Describe the extraction of metal from concentrated ore?
Ans: Metals occur in Earth’s crust mainly in the form of oxides, sulphides,
carbonates. The extraction is based on Activity series.
A. Metals with Low reactivity:
They
include Gold (Au), Silver (Ag), Copper (Cu), Mercury (Hg).
They are unreactive. They are reduced to metals by heating in presence of
oxygen. This process is called roasting.
E.g; HgS +
O2 ___> HgO + SO2 ___> Hg + O2
B. Metals
with medium reactivity:
They
include Iron (Fe), Zinc (Zn), Lead (Pb), Copper (Cu)
Their occur in form of Sulphite or Carbonate ores. They are oxidized by
following ways;
Roasting: Sulphite ores are heated in presence of oxygen to form
oxides.
This process is called roasting.
E.g. ZnS + O2
____> ZnO + SO2
Calcination: Carbonate ores are heated in absence of oxygen to form
oxides
E.g. ZnCO3 ____>
ZnO + CO2
The metals are obtained from the oxides by reduction. Carbon is used as
reducing agent.
C. Metals
with High reactivity:
They Include Potassium (K), Sodium (Na), Calcium (Ca).
The metals are produced in molten state by process of electrolytic reduction.
Q. Explain the process of Refining of metals?
Ans: The metals produced after extraction are usually impure. They need to be
refined.
The refining of metals is done by electrolytic refining.
Impure metal is used as an Anode (+ve electrode) where as pure form of same
metal is used as cathode ( -ve electrode). The metal salt is used as
electrolyte.
Metal from anode gets deposited at cathode.
E.g. Copper, zinc, Silver, Gold are refined electrolytically.
Q. Explain
the meaning of malleable and ductile?
Ans: Malleable: A substance is said to be malleable if it can be beaten
into sheets. E.g Metals
Ductile: A substance is said to be ductile if its can be drawn into
wires. E.g Metals
Q. Why is sodium kept immersed in kerosene oil?
Ans: Sodium is kept immersed in kerosene oil because sodium reacts with both
air and water.
Na + O2 _____> Na2O
Na2O + H2O _____> NaOH
Q. Write the equations for the reactions of:
a. Iron with steam: Iron forms Ferric oxide with steam:
3 Fe
+ 4 H2O _____>
Fe3O4 + 4 H2
b. Calcium and Potassium with water: Calcium and potassium form
calcium hydroxide and Pottasium hydroxide with water.
Ca + 2
H2O _____> Ca(OH)2
+ H2
K + H2O
_____> 2 KOH + H2
Q. Which gas is produced when dilute hydrochloric acid is added to a
reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4?
Ans: Hydrogen gas is produced when dilute HCl is added to reactive metal.
Fe + H2SO4 _____>
FeSO4 + H2
Q. What would you observe when zinc is added to solution of Iron (II)
sulphate. Write the chemical reaction that takes place?
Ans: When zinc is added to Iron (II) sulphate, it is displace Iron from the
compound.
Zn +
FeSO4 _____> ZnSO4 + Fe
The light green colour will slowly fade away.
Q. Define the terms:
a. Mineral: The compounds of elements along with impurities
occuring in earths crust are called minerals.
b. Ore: An Ore is mineral from which the element is extracted.
c. Gangue: The impurities present in the ore is called gangue.
Q. Name two metals which are found in nature in the free state?
Ans: Gold ( Au), Platinum (Pt) etc.
Q. What are alloys? In what way alloys are better than constituting
metals?
Ans: Alloys are the homogenous mixtures of two or more metals or metal and non
metal. E.g. Brass, Steel etc.
Alloys are
better than constituting because hey are more resistant to corrosion and are
hard and strong than constituting metals.
Q. What are amphoteric oxides? Give two examples?
Ans: Amphoteric oxides are metal oxides which react both with acids and bases
to produce salt and water. Examples of amphoteric oxides are zinc oxides,
Aluminium Oxides.
Q. Name two metals which will displace hydrogen from dilute acids and two metals which will not?
Ans: Zinc and Magnesium will displace hydrogen from dilute acids.
Gold and silver will not displace hydrogen from dilute acids.
Q. In the electrolytic refining of metal M, what would you take as anode, cathode and the electrolyte?
Ans: The impure metal is taken as anode, the pure metal is taken as cathode. The salt of metal M will be taken as an electrolyte.
Q. State two ways of preventing rusting?
Ans: The rust can be prevented by painting, Oiling, Greasing, Alloying
etc.
Q. Platinum, Gold, Silver are used to make Jewellery?
Ans: Platinum, Gold, Silver are used to make jewellery because they have
lusture and do not undergo corrosion.
Q. Why pure
gold is not suitable for making Jewellery?
Ans: Pure gold is very soft and can't be used for making ornaments. so, some amount of other metal such as copper or silver is added to make gold a bit harder.
Q. Sodium, Potassium and Lithium are stored under oil?
Ans: Sodium, Potassium and lithium are stored under oil because they react with
both air and water. E.g. Na
+ O2 ____> Na2O
Na2O + H2O
_____> NaOH
Q. Give reasons why Aluminium is highly reactive metal, yet it is used to make utensils for cooking?
Ans: Aluminium forms layer of aluminium oxide on its surface, which prevents
aluminium from further reaction. Aluminium oxides are stable at high
temperatures.
Q. Carbonate and sulphide ores are usually converted into oxides during process of extraction?
Ans: Ores are converted into oxides as it is easy to obtain metal from oxides
as compared to carbonates and sulphides.
Q. You must have seen tarnished copper vessels being cleaned with lemon juice. Explain why these sour substances are effective in cleaning the vessels.
Ans: The tarnished copper vessels have a layer of copper carbonate. The lemon
juice is acidic and dissolves the basic coating of copper carbonate.
Q. Describe the important properties of ionic compounds?
Ans: A. Ionic compounds contain Ions, Cations and Anions.
B. They are crystalline solids.
C. They have high Melting point and boiling points.
D. They are hard but brittle.
Q. Name one ore of Sodium. Write the chemical formula of sodium compound present in this ore.
The ore of
sodium is rock salt. Its formula is NaCl.
Q.
Differentiate between minerals and ores with the help of examples.
Ans:
|
Mineral |
Ore |
|
Minerals are
natural substances that occur inside the earth. |
Ore are
minerals from which metal can be extracted |
|
All minerals
are not ores |
All ores are
minerals |
|
Example: Salt,
Clay, Marble |
Example:
Bauxite, Hematite, Rock salt. |
Q. Why Sodium,
Potassium and Lithium are stored under the oil.
Q. Arrange the following elements in the order of their decreasing metallic character:
Sodium Na, Silicon Si,
Chlorine Cl, Magnesium Mg, Aluminium Al.
Ans: Since Metallic character decreases from Left to Right, Therefore,
Sodium Na > Magnesium Mg > Aluminium Al > Silicon Si > Chlorine Cl.
Q. Give an
example of metal which is a liquid at room temperature?
Q. Give an
example of metal which can be easily cut with the knife?
Q. Give an
example of metal which is the best conductor of heat.
Q. Give an
example of metal which is poor conductor of heat?
Ans: The metal which is poor conductor is heat is Lead (Pb)
|
Metal |
Iron Sulphate |
Copper
Sulphate |
Zinc Sulphate |
Silver Nitrate |
|
A |
No Rxn |
Displacement |
|
|
|
B |
Displacement |
|
No Rxn |
|
|
C |
No Rxn |
No Rxn |
No Rxn |
Displacement |
|
D |
No Rxn |
No Rxn |
No Rxn |
No Rxn |
i. Which is the most reactive metal
Ans: From the
table, B seems to be the most reactive metal.
ii. What would you observe if B is added to the solution of Copper Sulphate
Ans: If B is
added to the solution of copper sulphate, It will displace copper from the
solution.
iii. Arrange the metals A, B, C, D in the order of decreasing reactivity.
Ans: Most
reactive = B
Second Most
reactive = A
Third most
reactive = C
Least reactive =
D
Q. Write the
electron dot structure of sodium, oxygen and magnesium
Ans:
Q. Show the
formation of Na2O and MgO by the transfer of electrons.
Ans:
Q. Why do ionic
compounds have high melting points?
It takes lot of
energy to break these bonds. Therefore, they have high melting and boiling points.
Q. What chemical
process is used for obtaining a metal from its oxide?
Q. Metal oxides of Zinc, Magnesium and Copper were heated with the following metals:
|
Metal |
Zinc |
Magnesium |
Copper |
|
Zinc Oxide |
|
|
|
|
Magnesium
Oxide |
|
|
|
|
Copper Oxide |
|
|
|
Ans:
|
Metal |
Zinc |
Magnesium |
Copper |
|
Zinc Oxide |
No |
Yes |
No |
|
Magnesium
Oxide |
No |
No |
No |
|
Copper Oxide |
Yes |
Yes |
No |
Q. You are given
a hammer, a battery, a bulb, wires and a switch. How could you use them to
distinguish between samples of metals and non metals?
a. We can use
Hammer to hit metals and non metals. The metals are sonorous and will produce
the ringing sound.
Q. Fawad took
Sulphur powder on a spatula and heated it. He collected the gas evolved by
inverting a test tube over it.
Ans: The gas
evolved will be Sulphur dioxide. The sulphur dioxide will not change the colour
of dry litmus paper but the moist litmus paper will turn Red.
This is because
oxides of Non metals are generally acidic in nature.
Ans: S + O2 ->
SO2
Q. Which types
of oxides are formed when non metals combine with oxygen?
Q. Give reasons
why copper is used to make hot water tanks and not steel?
This will
corrode the tank.
Copper on the
other does not react with hot water or steam.
Aqua Regia
dissolves metals like gold and silver in it.
Q. Why
Platinum, Gold and Silver are used to make Jewellery?
Ans: They do not react with
air and do not corrode easily. Upon that they are lustrous as well.
Q. What is
corrosion? Name any two metals which do not corrode easily.
The two metals
which doesn’t corrode easily are Gold and Silver.
Q. What are
the various methods to prevent Corrosion?
Q. What are
Metals? State two physical properties of Metals.
Objective Type Questions:
Q.
Metals obtained by electrolytic reduction are:
A. Low in activity series B. In middle of activity series C. Towards top
of activity series
D. Both A and B
Ans: C.
Towards top of activity series
Q. Assertion:
When a Copper object remains exposed to air for the long time, It loses its lustre,
Reason: Cooper reacts with atmospheric gases to form green coating of copper
carbonate on its surface.
Ans: Both Assertion and
reason are true and R is correct explanation of A.
Q. Which among the following exist in native state in nature;
I. Cu
(Copper) II. Au (Gold) III. Zn (Zinc)
IV. Ag (Silver)
Ans: B.
II and IV (Gold and Silver)
Q. During
electrolytic refining of zinc, it gets:
A. Deposited at cathode B. Deposited at anode C.
Deposited at both cathode and anode
Ans: A.
Deposited at cathode
Q. Metals obtained by electrolytic reduction are:
A. Low in activity series B. In middle
of activity series C. Towards the top
of activity series
Ans: C.
Towards the top of activity series
Q. Amalgam is an alloy of;
a.) copper and zinc b.) Metal and mercury c.) sodium and potassium d.) iron
and carbon
Ans:- metal
and mercury.
Q. The metal which is liquid at room temperature is;
a.) Mercury b.) silver c.)
copper d.)
Aluminium
Ans:--Mercury.
Q. Aqua regia is a mixture of;
a.) conc. HCl and conc. HNO3 (3:1)
b.) conc. H2SO4 and conc. HNO3 ( 3:1)
c.) conc. HNO3
and conc. HCl (3:1)
Ans:-- Conc.
HCl and conc. HNO3 (3:1)
Q. Metal which has no action with water is;
a.) sodium
b.) calcium c.)
Magnesium d.) Gold
Ans:- gold
Q. The flux used in blast furnace to remove the unwanted impurities is;
a.) basic b.)
acidic c.)
neutral d.) amphoteric
Ans:-- basic
Q. The non metal which is a good conductor of electricity;
a.) sulphur
b.) Graphite c.)
Phosphorus d.) iodine
Ans:--
Graphite
Q. which non metal is liquid at room temperature?
a.) carbon b.)
sulphur c.) bromine d.)
oxygen
Ans:-- Bromine
Q. which is the most malleable metal?
a.) Gold b.) lead c.)
iron d.) copper
Ans:-- Gold
Q. The metal which will displace zinc from znso4 solution is;
a.) copper b.) silver c.)
Magnesium d.) iron
Ans:-Magnesium
Q. Metals of low reactivity are extracted by;
a.) heating alone b.)
electrolysis c.)
reduction
d.) none
Ans:--
Heating alone
Q. Most of highly reactive metals are extracted by:
A. Heating alone B. Reduction C.
Electrolysis D.
None
Ans: C.
Electrolysis.
Q. Which of following is an Iron Ore?
A.
Cinnabar B. Calamite C.
Haematite D. Rock Salt
Ans: C.
Haematite.
Q. The process of extraction of metal from its ore is called?
A.
Smelting
B. Refining C.
Metallurgy D.
Calcination
Ans: C.
Metallurgy
Q. which of the following is Amphoteric oxide?
a.)
co2 b.)
ZnO c.) Na2O
d.) K2O
Ans:-- ZnO
Q. which of the following methods is suitable for preventing an iron pan
from rusting;
a.) applying grease b.) applying paint c.)
applying coating of zinc d.) all of the
above
Ans:--
Applying a coating of zinc
Q. Food cans are coated with tin and not zinc because;
a.)zinc is
costlier than tin b.)
zinc has higher melting point than tin
c.) zinc is more reactive than tin d.)
zinc is less reactive than tin.
Ans:-- C,
Zinc is more reactive than Tin
Q. Which of following pairs will give displacement reactions?
a. NaCl solution and Copper metal b.
MgCl2 solution and Aluminium metal
c. FeSO4 solution and silver metal d.
AgNO3 solution and copper metal
Ans: d. AgNO3 solution and copper metal.
Q. Which one of these following four metals would be displaced from the
solution of its salts by other three metals?
A. Magnesium B. Silver C. Zinc D. Copper
Q. Arrange the following elements in the order of their decreasing metallic
character:
Sodium
Na, Silicon Si, Chlorine Cl, Magnesium Mg, Aluminium Al.
Ans: Sodium Na > Magnesium Mg > Aluminium Al > Silicon Si >
Chlorine Cl.
Q.
Assertion(A): Metalloids are classified as semi-metals
Reason (R):
Metalloids are intermediate in properties then exhibit properties of both
metals and non- metals.
Ans: A and R are
true and R is correct explanation of A
Q. Which
among the following is the least reactive metal:
a. Sodium b.
Zinc c. Mercury d.
Aluminium
Ans: c.
Mercury
Q. Aluminium
is used for making cooking utensils. Which of the following properties of
aluminium are responsible for the same?
a. Good thermal
conductivity b. Good
electrical conductivity c. Ductility d. High melting
point
Ans: Good
thermal conductivity and High Melting point
Q. Which one
of the following properties is not generally exhibited by ionic compounds?
a. Solubility in
water b. Electric conductivity in Solid state
c. High M.P and
B.P d. Electric conductivity in
Molten state
Ans: b. Electric
conductivity in Solid state
Q. Which of
the following oxides of iron would be obtained on prolonged reaction with
steam?
a.
FeO b. Fe2O3 and
Fe3O4 c.
Fe3O4 d. Fe2O3
Ans: c. Fe3O4
Q. Metals can be beaten into thin sheets. This property is called:
(A) Metallic lustre (B) Malleability (C) Ductility (D) Conductivity
Ans: (B) Malleability
Q. Which of the following methods is suitable for preventing an iron frying pan from rusting?
(A) Applying grease (B) Applying paint (C) Applying coating of zinc (D) All of these
Ans: (C) Applying coating of zinc
