Molecular Mass, Mole Concept and Concentration

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JEE Advanced 2016

LEVELJEE Advanced

The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 g cm $^{- 3}$ . The ratio of the molecular weights of the solute and solvent, $(\frac{M W _{solute}}{M W _{solvent}})$ , is

JEE Advanced 2022

LEVELJEE Advanced

To check the principle of multiple proportions, a series of pure binary compounds ( $P_{m} Q_{n}$ ) were analyzed and their composition is tabulated below. The correct option(s) is(are) \begin{array}{|c|c|c|} \hline \text{Compound} & \text{Weight \% of P} & \text{Weight \% of Q} \\ \hline 1 & 50 & 50 \\ \hline 2 & 44.4 & 55.6 \\ \hline 3 & 40 & 60 \\ \hline \end{array}

* Multiple Correct Options

(A)

If empirical formula of compound 3 is

P_{3} Q_{4}

, then the empirical formula of compound 2 is

P_{3} Q_{5}

(B)

If empirical formula of compound 3 is

P_{3} Q_{2}

and atomic weight of element P is 20, then the atomic weight of Q is 45.

(C)

If empirical formula of compound 2 is PQ, then the empirical formula of the compound 1 is

P_{5} Q_{4}

(D)

If atomic weight of P and Q are 70 and 35, respectively, then the empirical formula of compound 1 is

P_{2} Q

JEE Advanced 2014

LEVELJEE Main

A compound $H_{2} X$ with molar weight of $80 g$ is dissolved in a solvent having density of $0.4 g mL^{- 1}$ . Assuming no change in volume upon dissolution, the molality of a $3.2 molar$ solution is

JEE Advanced 2014

LEVELJEE Main

If the value of Avogadro number is $6.023 \times 1 0^{23} mol^{- 1}$ and the value of Boltzmann constant is $1.380 \times 1 0^{- 23} J K^{- 1}$ , then the number of significant digits in the calculated value of the universal gas constant is

JEE Advanced 2019

LEVELJEE Advanced

The mole fraction of urea in an aqueous urea solution containing 900 g of water is 0.05. If the density of the solution is $1.2 g cm^{- 3}$ , the molarity of urea solution is ___ (Given data : Molar masses of urea and water are $60 g mol^{- 1}$ and $18 g mol^{- 1}$ , respectively)

JEE Main 2020

LEVELJEE Main

The volume strength of $8.9 M H_{2} O_{2}$ solution calculated at $273 K$ and $1 atm$ is .......... . ( $R = 0.0821 L atm K^{- 1} mol^{- 1}$ ) (rounded off to the nearest integer).

LEVELJEE Main

A $5.2$ molal aqueous solution of methyl alcohol, $CH_{3} OH$ , is supplied. What is the mole fraction of methyl alcohol in the solution ?

(A)

0.100

(B)

0.190

(C)

0.086

(D)

0.050

LEVELBoard

Which of the following concentration factor is affected by change in temperature?

The density of a solution prepared by dissolving $120 g$ of urea (mol. mass $= 60 u$ ) in $1000 g$ of water is $1.15 g/mL$ . The molarity of this solution is

(A)

0.50 M

(B)

1.78 M

(C)

1.02 M

(D)

2.05 M

JEE Main 2021

LEVELJEE Main

The number of significant figures in $50000.020 \times 1 0^{- 3}$ is ............ .

JEE Main 2020

LEVELJEE Main

The molarity of $HNO_{3}$ in a sample which has density $1.4 g/mL$ and mass percentage of $63%$ is ……… (Molecular weight of $HNO_{3} = 63$ )

LEVELJEE Main

In an organic compound of molar mass $108 g mol^{- 1}$ C, H and N atoms are present in $9 : 1 : 3.5$ by weight. Molecular formula can be

(A)

C_{6} H_{8} N_{2}

(B)

C_{7} H_{10} N

(C)

C_{5} H_{6} N_{3}

(D)

C_{4} H_{18} N_{3}

LEVELJEE Main

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)

be a function of the molecular mass of the substance

The mole fraction of a solute in a $100$ molal aqueous solution is ......... $\times 1 0^{- 2}$ (Round off to the nearest integer). [Given, atomic masses $H : 1.0 u$ , $O : 16.0 u$ ]

JEE Main 2014

LEVELJEE Main

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1 : 4$ . The ratio of number of their molecule is

(A)

1 : 4

(B)

7 : 32

(C)

1 : 8

(D)

3 : 16

JEE Main 2019

LEVELJEE Main

5 moles of $A B_{2}$ weight $125 \times 1 0^{- 3}$ kg and 10 moles of $A_{2} B_{2}$ weight $300 \times 1 0^{- 3}$ kg. The molar mass of $A (M_{A})$ and molar mass of $B (M_{B})$ in kg mol $^{- 1}$ are

(A)

M_{A} = 10 \times 1 0^{- 3}

and

M_{B} = 5 \times 1 0^{- 3}

(B)

M_{A} = 50 \times 1 0^{- 3}

and

M_{B} = 25 \times 1 0^{- 3}

(C)

M_{A} = 25 \times 1 0^{- 3}

and

M_{B} = 50 \times 1 0^{- 3}

(D)

M_{A} = 5 \times 1 0^{- 3}

and

M_{B} = 10 \times 1 0^{- 3}

JEE Main 2020

LEVELJEE Main

The hardness of a water sample containing $1 0^{- 3} M MgSO_{4}$ expressed as $CaCO_{3}$ equivalents (in ppm) is...... (molar mass of $MgSO_{4}$ is $120.37 g/mol$ )

JEE Main 2019

LEVELJEE Main

$8 g$ of $NaOH$ is dissolved in $18 g$ of $H_{2} O$ . Mole fraction of $NaOH$ in solution and molality (in $mol kg^{- 1}$ ) of the solution respectively are

(A)

0.2

11.11

(B)

0.167

22.20

(C)

0.2

22.20

(D)

0.167

11.11

LEVELJEE Main

The density (in $g mL^{- 1}$ ) of a $3.60 M$ sulphuric acid solution that is $29%$ $H_{2} SO_{4}$ (molar mass $= 98 g mol^{- 1}$ ) by mass will be

How many moles of magnesium phosphate, $Mg_{3} (PO_{4})_{2}$ will contain 0.25 mole of oxygen atoms?

(A)

0.02

(B)

3.125 \times 1 0^{- 2}

(C)

1.25 \times 1 0^{- 2}

(D)

2.5 \times 1 0^{- 2}

JEE Main 2021

LEVELBoard

If the concentration of glucose ( $C_{6} H_{12} O_{6}$ ) in blood is $0.72 gL^{- 1}$ , the molarity of glucose in blood is ...... $\times 1 0^{- 3} M$ . (Nearest integer) [Given : Atomic mass of $C = 12$ , $H = 1$ , $O = 16 u$ ]

JEE Main 2020

LEVELJEE Advanced

A solution of two components containing $n_{1}$ moles of the 1st component and $n_{2}$ moles of the 2nd component is prepared. $M_{1}$ and $M_{2}$ are the molecular weights of component 1 and 2 respectively. If $d$ is the density of the solution in $g mL^{- 1}$ , $C_{2}$ is the molarity and $χ_{2}$ is the mole-fraction of the 2nd component, then $C_{2}$ can be expressed as

(A)

C_{2} = \frac{1000 χ _{2}}{M _{1} + χ _{2} ( M _{2} - M _{1} )}

(B)

C_{2} = \frac{d χ _{2}}{M _{2} + χ _{2} ( M _{2} - M _{1} )}

(C)

C_{2} = \frac{1000 d χ _{2}}{M _{1} + χ _{2} ( M _{2} - M _{1} )}

(D)

C_{2} = \frac{d χ _{1}}{M _{2} + χ _{2} ( M _{2} - M _{1} )}

JEE Main 2021

LEVELJEE Main

The number of atoms in 8 g of sodium is $x \times 1 0^{23}$ . The value of $x$ is ……… . (Nearest integer) [Given : $N_{A} = 6.02 \times 1 0^{23} mol^{- 1}$ Atomic mass of Na = $23.0 u$ ]

JEE Main 2020

LEVELJEE Main

The mass percentage of nitrogen in histamine is ………

LEVELBoard

$6.02 \times 1 0^{20}$ molecules of urea are present in $100 mL$ of its solution. The concentration of urea solution is (Avogadro constant, $N_{A} = 6.02 \times 1 0^{23} mol^{- 1}$ )

(A)

0.001 M

(B)

0.01 M

(C)

0.02 M

(D)

0.1 M

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The volume strength of 8.9 M H2​O2​ solution calculated at 273 K and 1 atm is .......... . (R=0.0821 L atm K−1mol−1) (rounded off to the nearest integer).

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A 5.2 molal aqueous solution of methyl alcohol, CH3​OH, is supplied. What is the mole fraction of methyl alcohol in the solution ?

Which of the following concentration factor is affected by change in temperature?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The density of a solution prepared by dissolving 120 g of urea (mol. mass =60 u) in 1000 g of water is 1.15 g/mL. The molarity of this solution is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The number of significant figures in 50000.020×10−3 is ............ .

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The molarity of HNO3​ in a sample which has density 1.4 g/mL and mass percentage of 63% is ……… (Molecular weight of HNO3​=63)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } In an organic compound of molar mass 108 g mol−1 C, H and N atoms are present in 9:1:3.5 by weight. Molecular formula can be

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } 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

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The mole fraction of a solute in a 100 molal aqueous solution is ......... ×10−2 (Round off to the nearest integer). [Given, atomic masses H:1.0 u, O:16.0 u]

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1:4. The ratio of number of their molecule is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } 5 moles of AB2​ weight 125×10−3 kg and 10 moles of A2​B2​ weight 300×10−3 kg. The molar mass of A(MA​) and molar mass of B(MB​) in kg mol−1 are

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The hardness of a water sample containing 10−3 M MgSO4​ expressed as CaCO3​ equivalents (in ppm) is...... (molar mass of MgSO4​ is 120.37 g/mol)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } 8 g of NaOH is dissolved in 18 g of H2​O. Mole fraction of NaOH in solution and molality (in mol kg−1) of the solution respectively are

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The density (in g mL−1) of a 3.60 M sulphuric acid solution that is 29% H2​SO4​ (molar mass =98 g mol−1) by mass will be

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } How many moles of magnesium phosphate, Mg3​(PO4​)2​ will contain 0.25 mole of oxygen atoms?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The number of atoms in 8 g of sodium is x×1023. The value of x is ……… . (Nearest integer) [Given : NA​=6.02×1023 mol−1 Atomic mass of Na = 23.0 u]

The mass percentage of nitrogen in histamine is ………

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } 6.02×1020 molecules of urea are present in 100 mL of its solution. The concentration of urea solution is (Avogadro constant, NA​=6.02×1023 mol−1)

The volume strength of $8.9 M H_{2} O_{2}$ solution calculated at $273 K$ and $1 atm$ is .......... . ( $R = 0.0821 L atm K^{- 1} mol^{- 1}$ ) (rounded off to the nearest integer).

A $5.2$ molal aqueous solution of methyl alcohol, $CH_{3} OH$ , is supplied. What is the mole fraction of methyl alcohol in the solution ?

The density of a solution prepared by dissolving $120 g$ of urea (mol. mass $= 60 u$ ) in $1000 g$ of water is $1.15 g/mL$ . The molarity of this solution is

The number of significant figures in $50000.020 \times 1 0^{- 3}$ is ............ .

The molarity of $HNO_{3}$ in a sample which has density $1.4 g/mL$ and mass percentage of $63%$ is ……… (Molecular weight of $HNO_{3} = 63$ )

In an organic compound of molar mass $108 g mol^{- 1}$ C, H and N atoms are present in $9 : 1 : 3.5$ by weight. Molecular formula can be

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

The mole fraction of a solute in a $100$ molal aqueous solution is ......... $\times 1 0^{- 2}$ (Round off to the nearest integer). [Given, atomic masses $H : 1.0 u$ , $O : 16.0 u$ ]

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1 : 4$ . The ratio of number of their molecule is

5 moles of $A B_{2}$ weight $125 \times 1 0^{- 3}$ kg and 10 moles of $A_{2} B_{2}$ weight $300 \times 1 0^{- 3}$ kg. The molar mass of $A (M_{A})$ and molar mass of $B (M_{B})$ in kg mol $^{- 1}$ are

The hardness of a water sample containing $1 0^{- 3} M MgSO_{4}$ expressed as $CaCO_{3}$ equivalents (in ppm) is...... (molar mass of $MgSO_{4}$ is $120.37 g/mol$ )

$8 g$ of $NaOH$ is dissolved in $18 g$ of $H_{2} O$ . Mole fraction of $NaOH$ in solution and molality (in $mol kg^{- 1}$ ) of the solution respectively are

The density (in $g mL^{- 1}$ ) of a $3.60 M$ sulphuric acid solution that is $29%$ $H_{2} SO_{4}$ (molar mass $= 98 g mol^{- 1}$ ) by mass will be

How many moles of magnesium phosphate, $Mg_{3} (PO_{4})_{2}$ will contain 0.25 mole of oxygen atoms?

The number of atoms in 8 g of sodium is $x \times 1 0^{23}$ . The value of $x$ is ……… . (Nearest integer) [Given : $N_{A} = 6.02 \times 1 0^{23} mol^{- 1}$ Atomic mass of Na = $23.0 u$ ]

$6.02 \times 1 0^{20}$ molecules of urea are present in $100 mL$ of its solution. The concentration of urea solution is (Avogadro constant, $N_{A} = 6.02 \times 1 0^{23} mol^{- 1}$ )