List of top Chemistry Questions on Mole concept and Molar Masses asked in JEE Main

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is:

The molar mass of the water insoluble product formed from the fusion of chromite ore $FeCr_2\text{O}_4$ with $Na_2\text{CO}_3$ in presence of $O_2$ is ....... g mol$^{-1}$:

0.1 mol of the following given antiviral compound (P) will weigh .........x $ 10^{-1} $ g.

Among $ 10^{-10} $ g (each) of the following elements, which one will have the highest number of atoms?
Element : Pb, Po, Pr and Pt

The molar mass of the water insoluble product formed from the fusion of chromite ore $FeCr_2\text{O}_4$ with $Na_2\text{CO}_3$ in presence of $O_2$ is ....... g mol$^{-1}$:

0.1 mole of compound S will weigh ...... g, (given the molar mass in g mol$^{-1}$ C = 12, H = 1, O = 16)

2.8 $ \times 10^{-3} $ mol of $ \text{CO}_2 $ is left after removing $ 10^{21} $ molecules from its ‘$ x $’ mg sample. The mass of $ \text{CO}_2 $ taken initially is: Given: $ N_A = 6.02 \times 10^{23} \, \text{mol}^{-1} $

When '$x \times 10^{-2} \, \text{mL}$' methanol (molar mass $= 32 \, \text{g}$; density $= 0.792 \, \text{g/cm}^3$) is added to $100 \, \text{mL}$ water (density $= 1 \, \text{g/cm}^3$), the following diagram is obtained.

x = __________ (nearest integer)
[Given: Molal freezing point depression constant of water at $273.15 \, \text{K}$ is $1.86 \, \text{K kg mol}^{-1}$]

Molality $(m)$ of $3 \, \text{M}$ aqueous solution of $\text{NaCl}$ is:
(Given: Density of solution $= 1.25 \, \text{g mL}^{-1}$, Molar mass in $\text{g mol}^{-1}$: $\text{Na} = 23, \, \text{Cl} = 35.5$)

Ail organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is :

A sample of $ \text{CaCO}_3 $ and $ \text{MgCO}_3 $ weighed 2.21 g is ignited to constant weight of 1.152 g. The composition of the mixture is:
(Given molar mass in g mol$^{-1}$)

Calculate the Molarity of a Solution having density = $1.5$ $g/ml$. $\%(w/w)$ of Solute is $36\%$ and Molecular weight of Solute is $36$ $g/mol$

Number of moles of $H^+$ required by $1$ mole $MnO_4^-$ to oxidize oxalate ion to $CO_2$ is ____ .

If a substance ‘A’ dissolves in a solution of a mixture of ‘B’ and ‘C’ with their respective number of moles as $n_a$, $n_b$, and $n_c$, the mole fraction of C in the solution is:

The mass of sodium acetate (CH₃COONa) required to prepare 250 mL of 0.35 M aqueous solution is g. (Molar mass of CH₃COONa is 82.02 g/mol)

Calculate the Molarity of a Solution having density = $1.5$ $g/ml$. $\%(w/w)$ of Solute is $36\%$ and Molecular weight of Solute is $36$ $g/mol$

Assume carbon burns according to following equation :
$2 C _{( s )}+ O _{2( g )} \rightarrow 2 CO ( g )$
When $12 g$ carbon is burnt in $48 g$ of oxygen, the volume of carbon monoxide produced is___ $\times 10^{-1} L$ at STP. [nearest integer]
[Given : Assume $CO$ as ideal gas, Mass of $C$ is $12\, g \,mol ^{-1}$, Mass of $O$ is $16 \,g \,mol ^{-1}$ and molar volume of an ideal gas at STP is $22.7\, L\, mol ^{-1}$ ]

Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH 12 is $x \times 10^{-1}$. The value of $x$ is — (Nearest integer).

For 1 mol of gas, the plot of pV vs. p is shown below. p is the pressure and V is the volume of the gas. What is the value of compressibility factor at point A?

The volume of HCl, containing $73 g L^{−1}$, required to completely neutralise NaOH obtained by reacting $0.69 g$ of metallic sodium with water, is _______ mL.( Nearest Integer)
(Given : molar Masses of Na, Cl, O, H, are 23,35.5,16 and 1 $g mol^{−1}$ respectively)

The number of molecules or ions from the following, which do not have odd number of electrons are ______.
(A) NO₂
(B) ICI₄^-
(C) BrF₃
(D) CIO₂
(E) NO₂²⁺
(F) NO

A solution is prepared by adding 2 g of X” to 1 moIe of water. Mass percent of “X” in the solution is

One mole of P₄ reacts with 8 moles of SOCI₂ to give 4 moles of A. x mole of SO₂ and 2 moles of B. A, B and x respectively are

The volume of hydrogen liberated at STP by treating 2.4 g of magnesium with excess of hydrochloric acid is _________ × 10^–2 L
Given : Molar volume of gas is 22.4 L at STP.
Molar mass of magnesium is 24 g mol^–1

Compound A contains 8.7% Hydrogen, 74% Carbon and 17.3% Nitrogen. The molecular formula of the compound is,
Given : Atomic masses of C, H and N are 12, 1 and 14 amu, respectively.
The molar mass of the compound A is 162g mol^–1.