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Mole Concept

Mole Concept

Trending Questions

Q.

Balance the equation: ${CaCO}_{3} + HCl \to {CaCl}_{2} + H_{2} O + {CO}_{2}$

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Q.

What is the molar mass of iron?

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Q.

Balance the reaction: Phosphorus burns in Chlorine gas to form Phosphorus pentachloride.

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Q. 250 mL of a sodium carbonate solution contains 2.65 g of

N a_{2} C O_{3}

. If 10 mL of this solution is diluted to 1 L, what is the concentration of the resultant solution?
(Molar mass of

N a_{2} C O_{3}

= 106 g/mol)

0.001 M
0.01 M
0.1 M
$10^{- 4}$ M

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Q. A carbon compound containing carbon and oxygen has approximate molar mass equal to

290

. On analysis it is found to contain 50% by mass of each element. Therefore molecular formula of the compound is

$C_{12} O_{9}$
$C_{4} O_{3}$
$C_{3} O_{4}$
$C_{9} O_{12}$

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Q. The total number of electrons in

1.6 g

of

C H_{4}

to that in

1.8 g

of

H_{2} O

is:

Double
The same
Triple
One fourth

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Q. The weight of

181.60 mL

of a diatomic gas at

0^{\circ} C

and

1 bar

pressure is

1 g

. The mass of one molecule (in g) of the gas is:

(N_{A}

is the Avogadro's constant)

$\frac{62.5}{N_{A}}$
$\frac{125}{N_{A}}$
$\frac{120}{N_{A}}$
$\frac{75.5}{N_{A}}$

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Q.

3.011 \times 10^{23}

molecules of a gas weigh

14 g

. Calculate the molecular mass of the gas.

$18 u$
$12 u$
$14 u$
$28 u$

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Q. The pressure of a

1 : 4

mixture by moles of dihydrogen and dioxygen enclosed in a vessel is one bar. What will be the partial pressure of dioxygen?

$0.8 \times 10^{4} bar$
$0.008 N m^{- 2}$
$8 \times 10^{4} N m^{- 2}$
$0.08 bar$

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Q.

Differentiate between a balanced and a skeletal chemical equation.

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Q.

The gram formula mass of $Z n S O_{4}$ is g.
(Given molar mass of $Z n$ in 65 g/mol)

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Q. The density of a 30% by mass solution of acetic acid in water is 1.250 g/mL. Its molarity is:

6.25 M
1.25 M
2.5 M
12.5 M

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Q. Phosphoric acid (

H_{3} P O_{4}

) is prepared in a two-step process.

P_{4} + 5 O_{2} \to P_{4} O_{10}

P_{4} O_{10} + 6 H_{2} O \to 4 H_{3} P O_{4}

186 g of phosphorus is made to react with excess oxygen which forms

P_{4} O_{10}

that has a 60 % yield. In the second reaction, 80% yield of

H_{3} P O_{4}

is obtained. The mass of

H_{3} P O_{4}

produced is:
(Molar mass of phosphorous = 31 g/mol)

282.24 g
149.95 g
125.47 g
564.48 g

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Q.

A glass of Water contains $5$ Moles of Water. How many molecules of water are present ?

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Q. Tetra phosphorus decaoxide combines with water to form phosphoric acid by the following unbalanced chemical equation:

P_{4} O_{10} + H_{2} O \to H_{3} P O_{4}

In order to form 105.0 g of phosphoric acid, how much tetraphosphorus decaoxide will you need?

262.6 g
138.1 g
75.97 g
72. 42 g

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Q.

No. of moles of water in $488.6 g$ of $B a C l_{2} .2 H_{2} O$ are (molecular weight of $B a C l_{2} .2 H_{2} O = 244.33$ )

2 moles
4 moles
3 moles
5 moles

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Q.

What is the relation between a mole and a molecule?

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Q. Calculate the percentage yield of sodium sulphate when 32.18 g of sulphuric acid reacts with excess sodium hydroxide to produce 37.91 g of sodium sulphate.

H_{2} S O_{4} + 2 N a O H (a q) \to 2 H_{2} O (l) + N a_{2} S O_{4} (a q)

91.37%
80.9%
78.13%
61.35%

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Q.

2 g

of butane is burnt with an excess of oxygen to form

C O_{2}

. What is the approximate amount of

C O_{2}

formed?

$3 g$
$1.5 g$
$6 g$
$2 g$

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Q. Find the number of O-atoms in

\frac{2}{3}

moles of

N O_{2}

.

$4.014 \times 10^{23}$
$4.014 \times 10^{20}$
$8.029 \times 10^{23}$
$8.029 \times 10^{20}$

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Q. Find the number of millimoles of

C H_{4}

in a sample containing

1.2044 \times 10^{21} C H_{4}

molecules.

2
0.002
20
0.02

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Q. There are two samples of

H C l

having concentrations of 1 M and 0.25 M. Find amongst the given options, the combination of these samples needed to prepare a 0.75 M

H C l

solution assuming no extra water is used.

50 mL, 20 mL
50 mL, 35 mL
20 mL, 10 mL
100 mL, 60 mL

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Q. Find the total number of oxygen atoms in

6 \times 10^{6}

formula units of the complex

[C o (H_{2} O)_{6}] C l_{2} .

$6 \times 10^{6}$
$3.6 \times 10^{7}$
$1.8 \times 10^{7}$
$4.2 \times 10^{7}$

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Q. A Solution of palmitic acid in benzene contains

4.24 g

of acid per litre. When this solution is dropped on a surface, benzene evaporates and palmitic acid forms a unimolecular film on the surface. If we wish to cover an area of

500 {cm}^{2}

with a unimolecular film, what volume of solution (in litres) should be used? The area covered by one palmitic acid molecule may be taken as

0.21 {nm}^{2}

.
Molecular weight of palmitic acid = 256

g m o l^{- 1}

.

$4.38 \times 10^{- 5}$
$2.4 \times 10^{- 5}$
$4 \times 10^{- 41}$
$56 \times 10^{5}$

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Q. When magnesium is placed in lead (II) sulphate solution, it reacts to form magnesium sulphate and lead. How much lead (II) sulphate would be required to react with 327 g of magnesium? (Molar mass of lead = 207 g/mol)

4128.4 g
1619.5 g
2788. 4 g
6868.4 g

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Q. What volume of air at

1 a t m

and

273 K

containing 21% of oxygen by volume is required to completely burn sulphur

(S_{8})

present in

200 g

of sample, which contains

20 %

inert material which does not burn. Sulpur burns according to the reaction

\frac{1}{8} S_{8} (s) + O_{2} (g) \to S O_{2} (g)

$23.52 L$
$320 L$
$112 L$
$533.33 L$

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Q. How much coulomb charge is present on 1g ion of

N^{3 -}

Note: 1 mole of electrons have a charge of 96500 C.

$5.2 \times 10^{6}$ Couloumb
$2.894 \times 10^{5}$ Couloumb
$6.6 \times 10^{6}$ Couloumb
$8.2 \times 10^{6}$ Couloumb

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Q.

The total weight of $10^{22}$ molecular units of $C u S O_{4} .5 H_{2} O$ is nearly

4.144 g
4.5 g
24.95 g
41.45 g

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Q. A sample of ammonium phosphate

(N H_{4})_{3} P O_{4}

contains

3.18 m o l

of hydrogen atoms. The number of moles of oxygen atoms in the sample is:

$0.265 m o l$
$0.795 m o l$
$1.06 m o l$
$4.00 m o l$

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Q. One mole of oxygen gas at STP is equal to_____.

$6.022 \times 10^{23}$ molecules of oxygen
$6.022 \times 10^{23}$ atoms of oxygen
$16 g$ of oxygen.
$32 g$ of oxygen.

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