1. Homogenous mixture is formed by mixing.
a) phenol and water
b) iron filing and sand
c) silver chloride and water
d) ethanol and water
Answer : d) ethanol and water
2. Atom is the smallest particle of
a) compound
b) substance
c) mixture
d) elements
Answer : d) elements
3. Molecule is the smallest particle of
a) compound
b) substance
c) mixture
d) elements
Answer : d) compound
4. Avagadro's number is the number of particles present in
a) 1 molecule
b) 1 atom
c) 1 kg
d) 1 mole
Answer : d) 1 mole
5. The temperature at absolute zero is
a) 273.15 0C
b) 0 0C
c) -373.15 0C
d) -273.15 0C
Answer : d) -273.15 C
6) SI unit of temperature is
a) Kelvin
b) 0C
c) 0F
d) Dalton
Answer : a) Kelvin
7. Atomicity of ammonium phosphate molecule is
a) 5
b) 10
c) 15
d) 20
Answer : d) 20
8. At STP 2 g of helium gas (molar mass = 4) occupies a volume of
a) 22.4 dm 3
b) 11.2 dm 3
c) 5.6 dm 3
d) 2 dm 3
Answer : b) 11.2 dm 3
9. The number of molecules in 22.4 cm 3 of nitrogen gas at STP is
a) 6.022 X 10 20
b) 6.022 X 10 23
c) 22.4 X 10 20
d) 22.4 X 10 23
Answer : a) 6.022 X 10 20
10. Number of moles of water in 1 litre of water with density 1 g/cc are
a) 55.56
b) 45.56
c) 56.55
d)56.55
Answer : a) 55.56
11. The physical state of a substance with lot of empty intermolecular space is
a) solid
b) liquid
c) gas
d) plasma
Answer : c) gas
12.The liquid with maximum viscosity is
a) water
b) acetone
c) glycol
d) glass
Answer : d) glass
13.The energy of electrons in the same subshell is
a) different
b) zero
c) infinite
d) same
Answer : d) same
14. Which of the following electrons have highest energy ?
a) 2s
b) 2p
c) 1s
d) 4p
Answer : d) 4p
15. The intermolecular force of attraction between methane molecules is
a) dipole-dipole interaction
b) ion-dipole interaction
c) dipole-induced dipole interaction
d) dispersion forces
Answer : d) dispersion forces
Chemistry, a branch of physical science, is the study of the composition, structure, properties and change of matter
.
Chemistry is chiefly concerned with atoms and their interactions with other atoms - for example, the properties of the chemical bonds formed between atoms to create chemical compounds. As well as this, interactions including atoms and other phenomena - electrons and various forms of energy—are considered, such as photochemical reactions, oxidation-reduction reactions, changes in phases of matter, and separation of mixtures. Finally, properties of matter such as alloys or polymers are considered.
A chemical reaction is a transformation of some substances into one or more different substances.
The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space called the electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively-charged electrons which orbit the nucleus.
A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z.
The mass number is the sum of the number of protons and neutrons in a nucleus.
A compound is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements.
A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances.
Avogadro law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules".
For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.
which can be written as:
V α n
or
V/n=k
where:
V is the volume of the gas
n is the amount of substance of the gas (measured in moles).
k is a constant equal to RT/P, where R is the universal gas constant, T is the Kelvin temperature, and P is the pressure. As temperature and pressure are constant, RT/P is also constant and represented as k.
A modern statement of Boyle's law is:
The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.
Mathematically, Boyle's law can be stated as
P α 1/V
or
PV = k
where P is the pressure of the gas, V is the volume of the gas, and k is a constant.
A modern statement of Charles's law is:
When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be directly related.This directly proportional relationship can be written as:
V α T
or
V/T=k
where:
V is the volume of the gas
T is the temperature of the gas (measured in Kelvin).
k is a constant.
Aldehydes and Ketones :-
Aldehydes and Ketones both have general formula CnH2nO and both contain (-CO-) group,hence often referred as carbonyl compounds.It is the carbonyl group that largely determines the chemistry of aldehydes and ketones.
H
|
H - C = O
H
|
R - C = O
Aldehyde
R
|
R - C = O
Ketone
a) Aldehyde : (R-CHO): In aldehydes the functional group is CHO and 'R' is an alkyl or aryl group .
Formaldehyde is an exception where there is no 'R' group.
H
|
R - C = O
Aldehyde
H
|
H - C = O
Formaldehyde
Since one of the valencies of the carbonyl carbon is attached to hydrogen, the aldehyde group occurs at the end of the chain.
b) Ketone (R-CO-R') :- In Ketones both available valencies of carbonyl carbon are attached to carbon atoms and so the keto group occurs within a chain.The groups R and R' may be aliphatic or aromatic.
R'
|
R - C = O
Ketones
CH3
|
CH3 - C = O
Acetone
CH3
|
C6H5 - C = O
Acetophenone
Rate of reactivity :-
Carbonyl carbon is always electron deficient and shows nucleophilic addition reaction .So by structural formula of aldehydes and ketones electron deficiebcy is more in aldehyde's carbonyl carbon i.e. partial positive charge (+ & #948;) as compare to ketones carbonyl carbon atom.
Analysis of aldehyde and ketones :-
1) Aldehydes shows silver mirror test that is aldehydes reduces Tollen's reagent.
Ketones does not give this test.
2) Aldehyde reduces Fehling solution to form red ppt of Cu2O.
Ketone does not give this test.
3) Aldehyde gives red colour with Schiff solution.
Ketones does not give this test.
4) Methyl Ketones and only acetaldehyde shows haloform reaction.
5) Both aldehydes and Ketones form Oxime,hydrazone and Semicarbazone derivatives.
a) phenol and water
b) iron filing and sand
c) silver chloride and water
d) ethanol and water
Answer : d) ethanol and water
2. Atom is the smallest particle of
a) compound
b) substance
c) mixture
d) elements
Answer : d) elements
3. Molecule is the smallest particle of
a) compound
b) substance
c) mixture
d) elements
Answer : d) compound
4. Avagadro's number is the number of particles present in
a) 1 molecule
b) 1 atom
c) 1 kg
d) 1 mole
Answer : d) 1 mole
5. The temperature at absolute zero is
a) 273.15 0C
b) 0 0C
c) -373.15 0C
d) -273.15 0C
Answer : d) -273.15 C
6) SI unit of temperature is
a) Kelvin
b) 0C
c) 0F
d) Dalton
Answer : a) Kelvin
7. Atomicity of ammonium phosphate molecule is
a) 5
b) 10
c) 15
d) 20
Answer : d) 20
8. At STP 2 g of helium gas (molar mass = 4) occupies a volume of
a) 22.4 dm 3
b) 11.2 dm 3
c) 5.6 dm 3
d) 2 dm 3
Answer : b) 11.2 dm 3
9. The number of molecules in 22.4 cm 3 of nitrogen gas at STP is
a) 6.022 X 10 20
b) 6.022 X 10 23
c) 22.4 X 10 20
d) 22.4 X 10 23
Answer : a) 6.022 X 10 20
10. Number of moles of water in 1 litre of water with density 1 g/cc are
a) 55.56
b) 45.56
c) 56.55
d)56.55
Answer : a) 55.56
11. The physical state of a substance with lot of empty intermolecular space is
a) solid
b) liquid
c) gas
d) plasma
Answer : c) gas
12.The liquid with maximum viscosity is
a) water
b) acetone
c) glycol
d) glass
Answer : d) glass
13.The energy of electrons in the same subshell is
a) different
b) zero
c) infinite
d) same
Answer : d) same
14. Which of the following electrons have highest energy ?
a) 2s
b) 2p
c) 1s
d) 4p
Answer : d) 4p
15. The intermolecular force of attraction between methane molecules is
a) dipole-dipole interaction
b) ion-dipole interaction
c) dipole-induced dipole interaction
d) dispersion forces
Answer : d) dispersion forces
Chemistry, a branch of physical science, is the study of the composition, structure, properties and change of matter
.
Chemistry is chiefly concerned with atoms and their interactions with other atoms - for example, the properties of the chemical bonds formed between atoms to create chemical compounds. As well as this, interactions including atoms and other phenomena - electrons and various forms of energy—are considered, such as photochemical reactions, oxidation-reduction reactions, changes in phases of matter, and separation of mixtures. Finally, properties of matter such as alloys or polymers are considered.
A chemical reaction is a transformation of some substances into one or more different substances.
The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space called the electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively-charged electrons which orbit the nucleus.
A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z.
The mass number is the sum of the number of protons and neutrons in a nucleus.
A compound is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements.
A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances.
Avogadro law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules".
For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.
which can be written as:
V α n
or
V/n=k
where:
V is the volume of the gas
n is the amount of substance of the gas (measured in moles).
k is a constant equal to RT/P, where R is the universal gas constant, T is the Kelvin temperature, and P is the pressure. As temperature and pressure are constant, RT/P is also constant and represented as k.
A modern statement of Boyle's law is:
The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.
Mathematically, Boyle's law can be stated as
P α 1/V
or
PV = k
where P is the pressure of the gas, V is the volume of the gas, and k is a constant.
A modern statement of Charles's law is:
When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be directly related.This directly proportional relationship can be written as:
V α T
or
V/T=k
where:
V is the volume of the gas
T is the temperature of the gas (measured in Kelvin).
k is a constant.
Aldehydes and Ketones :-
Aldehydes and Ketones both have general formula CnH2nO and both contain (-CO-) group,hence often referred as carbonyl compounds.It is the carbonyl group that largely determines the chemistry of aldehydes and ketones.
H
|
H - C = O
H
|
R - C = O
Aldehyde
R
|
R - C = O
Ketone
a) Aldehyde : (R-CHO): In aldehydes the functional group is CHO and 'R' is an alkyl or aryl group .
Formaldehyde is an exception where there is no 'R' group.
H
|
R - C = O
Aldehyde
H
|
H - C = O
Formaldehyde
Since one of the valencies of the carbonyl carbon is attached to hydrogen, the aldehyde group occurs at the end of the chain.
b) Ketone (R-CO-R') :- In Ketones both available valencies of carbonyl carbon are attached to carbon atoms and so the keto group occurs within a chain.The groups R and R' may be aliphatic or aromatic.
R'
|
R - C = O
Ketones
CH3
|
CH3 - C = O
Acetone
CH3
|
C6H5 - C = O
Acetophenone
Rate of reactivity :-
Carbonyl carbon is always electron deficient and shows nucleophilic addition reaction .So by structural formula of aldehydes and ketones electron deficiebcy is more in aldehyde's carbonyl carbon i.e. partial positive charge (+ & #948;) as compare to ketones carbonyl carbon atom.
Analysis of aldehyde and ketones :-
1) Aldehydes shows silver mirror test that is aldehydes reduces Tollen's reagent.
Ketones does not give this test.
2) Aldehyde reduces Fehling solution to form red ppt of Cu2O.
Ketone does not give this test.
3) Aldehyde gives red colour with Schiff solution.
Ketones does not give this test.
4) Methyl Ketones and only acetaldehyde shows haloform reaction.
5) Both aldehydes and Ketones form Oxime,hydrazone and Semicarbazone derivatives.
