Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 73

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IMPORTANT

Earn 100

$250 ml$ of $0.5 M KCl$ is diluted with water to $500 ml$ of solution, the number of chloride ions in the resulting solution are:

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Important Questions on Some Basic Concepts of Chemistry

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 74

The atmospheric pressure of Mars is

0.61 kPa

. What is the pressure in

mm Hg

?

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 75

At what temperature, both Celsius and Fahrenheit scale read the same value?

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 76

What volume of oxygen (In L) is required for complete combustion of

2.2 g

of propane at NTP?

EASY

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 77

The vapour density of a gas is $11.2 .$ Calculate the volume occupied by $11.2 g$ of the gas at NTP.

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JEE Main

IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 78

The dot at the end of this sentence has a mass of about one microgram. Assuming that the black stuff is carbon, calculate the approximate number of atoms of carbon needed to make such a dot. (

1

microgram

= 1 \times 10^{- 6} g

). If the number of atoms are

a \times 10^{16}

, determine the value of

' a'

. Take Avogadro Number =

6 \times 10^{23}

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 79

What weight (in gram) of ${CuSO}_{4} \cdot 5 H_{2} O$ must be taken to make $0.5 litre$ of $0.01 M Cu$ ion solution?

If the weight is x, express the answer as 4x.

Round off your answer to the nearest integer.

$(Cu = 63.5, S = 32, O = 16, H = 1)$

HARD

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 80

A flash bulb used for taking photographs in poor light contains

30 mL

of

O_{2}

at

780 mm Hg

pressure at

27 ° C

. Supposing that the metal wire flashed is pure

Al

which is oxidized to

{Al}_{2} O_{3}

in the process of flashing, calculate the minimum weight of

Al

wire that is to be used for maximum efficiency.

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IMPORTANT

Chemistry Crash Course JEE Main>Chapter 23 - Some Basic Concepts of Chemistry>Level 1>Q 81

To a sample of an element

X (at . wt . 70)

another element

Y (at . wt . 120)

is to be added as an impurity. The ratio of the atoms in the mixture is to be

1 : 10^{- 7}

. How many micrograms of

Y

will be required for

35 g

of

X ?