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MOLE CONCEPT AND MOLAR MASS - (Concept)
Mole:
-
A mole is a unit that represents 6.023 x 1023 particles, atoms, molecules or ions, etc., irrespective of their nature.
-
Mole is related to the mass of the substance, the volume of gaseous substance and the number of particles
-
Here G.m.m. = Gram molecular mass or molar mass which is the mass of 1 mole of any substance
-
-
The volume of one mole of any gas is equal to 22.4 litres or dm3 at STP. It is known as molar volume.
-
Relationship of Mole:
A mole of any substance (like O2) stands for:
-
6.023 x 1023 molecules of O2
-
2 x 6.023 x 1023 atoms of Oxygen
-
32 gm of Oxygen
-
22.4 litre of O2 at STP.
To Find the Total Number of Identities:
-
Total number of Molecule = mole(n) x NA
-
Total number of Atoms = mole (n) x NA x No. of atoms present in one molecule (atomicity).
-
Total number of Electrons = mole (n) x NA x No. of electron present in one atom.
-
Total charge on any ion = mole (n) x NA x charge on one ion x 1.6 x 10-19 C
| Exam | Chapter |
| JEE MAIN | Some basic concepts in chemistry |
Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is:
| A. |
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| B. |
|
| C. |
|
| D. |
|
If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will
| A. |
|
| B. |
|
| C. |
|
| D. |
|
A solution of sodium sulfate contains 92g of ions per kilogram of water. The molality of
ions in that solution in mol Kg-1 is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
of
weigh
and
of
weigh
The molar mass of
and molar mass of
in
are :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the molecular mass of H2SO4?
(response should be like 67 or 70)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
An unknown chlorohydrocarbon has 3.55% of chlorine. If each molecule of the hydrocarbon has one chlorine atom only; chlorine atoms present in 1 g of
chlorohydrocarbon are : (Atomic wt. of Cl=35.5 u;Avogadro constant= )
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The percentage composition of carbon by 1 mole in methane is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The minimum amount of consumed per gram of reactant is for the reaction :
(Given atomic mass :
,
)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which of the following has the maximum number of molecules?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the number of molecules in 16g of Oxygen?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
In the reaction,
| A. |
|
| B. |
|
| C. |
|
| D. |
|
One litre of a gas at STP weighs 1.16 g. The gas can possibly be
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The number of water molecules is maximum in :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The number of chlorine atoms in 20 mL of chlorine gas at STP is __________1021. (Round off to the Nearest Integer). [ Assume chlorine is an ideal gas at STP, R = 0.083 L bar mol-1 K-1, NA = 6.023 x1023]
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Complete combustion of 3 g of ethane gives molecules of water. The value of x is ________. (Round off to the Nearest Integer).
[Use : NA = 6.023 x 1023; Atomic masses in u : C : 12.0 ; O : 16.0 ; H : 1.0]
| A. |
|
| B. |
|
| C. |
|
| D. |
|
A reaction of 0.1 mole of Benzylamine with bromomethane gave 23 g of Benzyl trimethyl ammonium bromide. The number of moles of bromomethane consumed in this reaction are when n = _________. (Round off to the Nearest Integer).
[Given : Atomic masses : C : 12.0 u, H : 1.0 u, N : 14.0 u, Br : 80.0 u]
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The number of N atoms in 681 g of . The value of x is _________.
(Nearest Integer)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Two elements which form
moles of
type compounds. If both
weigh equally, then the atomic weight of A is____________ times of atomic weight of B.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The number of atoms in . The value of
is ___________.(Nearest integer)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
An organic compound contains C, H, and S. The minimum molecular weight of the compound containing 8% sulfur is :
(atomic weight of S = 32 amu)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Reaction of 6.0 g of A, 6.01023 atoms of B, and 0.036 mol of C yields 4.8 g of compound AB2C3. If the atomic mass of A and C are 60 and 80 amu, respectively, the atomic mass of B is (Avogadro no.=6
1023) :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The amount of oxygen in 3.6 moles of water is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Number of atoms in the following samples of substances is the largest in:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
of an ideal gas
occupies
at STP. The value of x is
| A. |
|
| B. |
|
| C. |
|
| D. |
|
How many moles of magnesium phosphate, will contain 0.25 mole of oxygen atoms?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the number of moles in 8g of Helium?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the mass (in g) of molecules of H3PO4?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Calculate the number of moles of carbon atoms in 39g of benzene.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the percentage mass of N in a mixture of 0.5 mole NH3 and 1 mole Ca(NO3)2?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the percentage purity of a sample of CaCO3 if 150g of the sample gives out 44g of CO2 on heating?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
What is the total number of moles if we have a mixture of 34g of Ammonia, 78g of Benzene and 10g Hydrogen?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
We have a substance . What is the molar mass (in g) of
if 2 moles of it weigh 196g?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
14 g Nitrogen gas and 22 g of CO2 gas are mixed together. Find the volume of gaseous mixture at STP.
(Response should be upto only one decimal digit like 78.7).
| A. |
|
| B. |
|
| C. |
|
| D. |
|
A compound possess 8% sulphur by mass. The least molecular mass is :
(Response should be in integer only like 100 or 1000).
| A. |
|
| B. |
|
| C. |
|
| D. |
|
In order to oxidise a mixture of one mole of each of and
in acidic medium, the number of moles of
required is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
of
surfactant solution forms a monolayer covering
on a polar substrate . If the polar head is approximated as a cube , what is its edge length (in pm) ?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If is the initial temperature and
is the final temperature, which of the following statements is correct?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The maximum prescribed concentration of copper in drinking water is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The label on a H2O2 bottle reads as 10 Vol. How many grams of H2O2 are present in 1 L of the solution?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The ratio of the masses percentages of and
of a saturated acyclic organic compound
are 4:1 and 3:4 respectively . Then , the moles of oxygen gas required for complete combustion of two moles of organic compound
is_____________
| A. |
|
| B. |
|
| C. |
|
| D. |
|
if moles of oxygen combine with
to form
, then the weight of
used in the reaction is (Al = 27 g/mol)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The moles of methane required to produce of water after complete combustion is __________
.[nearest integer]
| A. |
|
| B. |
|
| C. |
|
| D. |
|
on reaction with excess of water results into acidic mixture
16 moles of is required for the complete neutralisation of the resultant acidic mixture. The number of moles of
used is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
solution of
-glucose in water contains
of carbon by weight. The molality of the solution is nearest to
(Given: Atomic Weights are, )
| A. |
|
| B. |
|
| C. |
|
| D. |
|
If Avogadro number NA, is changed from 6.022 x 1023 mol-1 to 6.022 x 1020 mol-1, this would change :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which of the following has maximum number of molecules?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
How many moles of PCl5 needs to be heated to give 22.4 L of Cl2?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
How much CaCO3 and water must be weighed to make a solution that is 10% CaCO3?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The number of molecules and moles in 2.8375 litres of at STP are respectively
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Match List I with List II
Choose the correct answer from the options given below:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Find the molarity strength of a sample which is prepared by mixing of
(specific gravity
) and
of
of
(specific gravity
). Also, the specific gravity of the resultant mixture is 1.4 and assume there is no loss of mass during mixing.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
of solution was made by taking
of a sample of
having
as an impurity. Out of the prepared volume,
of the solution needed
of
solutions. What will be the composition in
| A. |
|
| B. |
|
| C. |
|
| D. |
|
of
metal was treated with
of
having specific gravity of 1.18 . After complete dissolution of the metal, the resultant solution was diluted to
. Find the molarity of free
in the final solution if
by weight was used.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
1 ml each of methane, ethane & propane requires exactly x, y & z ml of $\mathrm{O}_2$ respectively.
Find value of $x+y+z(\mathrm{ml})$
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The mass of silver (Molar mass of $\mathrm{Ag}: 108 \mathrm{gmol}^{-1}$ ) displaced by a quantity of electricity which displace 5600 $\mathrm{mL}$ of $\mathrm{O}_2$ at S.T.P will be________g.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Mass of methane required to produce $22 \mathrm{~g}$ of $\mathrm{CO}_2$ after complete combustion is___________ g.
(Given Molar mass in g $\begin{aligned} \mathrm{mol}^{-1} \mathrm{C} & =12.0 \\ \mathrm{H} & =1.0 \\ \mathrm{O} & =16.0)\end{aligned}$
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Volume of $3 \mathrm{M} \mathrm{NaOH}$ (formula weight $40 \mathrm{~g} \mathrm{~mol}^{-1}$ ) which can be prepared from $84 \mathrm{~g}$ of $\mathrm{NaOH}$ is $\times 10^{-1} \mathrm{dm}^3$_____$\times 10^{-1} \mathrm{dm}^3$.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
1 mole of $\mathrm{PbS}$ is oxidised by "X" moles of $\mathrm{O}_3$ to get "Y" moles of $\mathrm{O}_2 . \mathrm{X}+\mathrm{Y}=$______.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
$9.3 \mathrm{~g}$ of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is $100 \%$ completed is _______$\times 10^{-1} \mathrm{~g}$.
(Given molar mass in g mol -1 N : 14, O : 16, C : 12, H : 1)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
If 50 mL of 0.5M oxalic acid is required to neutralise 25 mL of NaOH solution, the amount of NaOH in 50 mL of given NaOH solution is _______ g.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
$0.05 \mathrm{~cm}$ thick coating of silver is deposited on a plate of $0.05 \mathrm{~m}^2$ area. The number of silver atoms deposited on plate are________$\times 10^{23}$. (At mass $\left.\mathrm{Ag}=108, \mathrm{~d}=7.9 \mathrm{~g} \mathrm{~cm}^{-3}\right)$
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The mass of sodium acetate $\left(\mathrm{CH}_3 \mathrm{COONa}\right)$ required to prepare $250 \mathrm{~mL}$ of $0.35 \mathrm{M}$ aqueous solution is_________ g. (Molar mass of $\mathrm{CH}_3 \mathrm{COONa}$ is $82.02 \mathrm{~g} \mathrm{~mol}^{-1}$ )
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Molar mass of the salt from $\mathrm{NaBr}, \mathrm{NaNO}_3, \mathrm{KI}$ and $\mathrm{CaF}_2$ which does not evolve coloured vapours on heating with concentrated $\mathrm{H}_2 \mathrm{SO}_4$ is_________ $\mathrm{g} \mathrm{mol}^{-1}$.
(Molar mass in $\mathrm{g} \mathrm{mol}^{-1}: \mathrm{Na}: 23, \mathrm{~N}: 14, \mathrm{~K}: 39, \mathrm{O}: 16, \mathrm{Br}: 80, \mathrm{I}: 127, \mathrm{~F}: 19, \mathrm{Ca}: 40$ )
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Number of moles of methane required to produce $22 \mathrm{~g} \mathrm{CO}_2(\mathrm{~g})$ after combustion is $\mathrm{x} \times 10^{-2}$ moles. The value of $\mathrm{x}$ is_________.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
A sample of $\mathrm{CaCO}_3$ and $\mathrm{MgCO}_3$ weighed $2.21 \mathrm{~g}$ is ignited to constant weight of $1.152 \mathrm{~g}$. The composition of mixture is: (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{CaCO}_3: 100, \mathrm{MgCO}_3: 84$ )
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Number of moles of $\mathrm{H}^{+}$ions required by 1 mole of $\mathrm{MnO}_4^{-}$to oxidise oxalate ion to $\mathrm{CO}_2$ is_______.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Consider the following reaction :
$3 \mathrm{PbCl}_2+2\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4 \rightarrow \mathrm{Pb}_3\left(\mathrm{PO}_4\right)_2+6 \mathrm{NH}_4 \mathrm{Cl}$
If $72 \mathrm{mmol}$ of $\mathrm{PbCl}_2$ is mixed with $50 \mathrm{mmol}$ of $\left(\mathrm{NH}_4\right)_3 \mathrm{PO}_4$, then the amount of $\mathrm{Pb}_3\left(\mathrm{PO}_4\right)_2$ formed is_______ mmol (nearest integer).
| A. |
|
| B. |
|
| C. |
|
| D. |
|
$10 \mathrm{~mL}$ of gaseous hydrocarbon on combustion gives $40 \mathrm{~mL}$ of $\mathrm{CO}_2(\mathrm{~g})$ and $50 \mathrm{~mL}$ of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is_______.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
