Tag: avogadro's law

Questions Related to avogadro's law

If  $N _ { A }$ is Avogadro's number, then calculate the number of electrons in  $4.2\ g$  of  $N ^ { 3- }$.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $2.1 N _ { A }$

  2. $3 N _ { A }$

  3. $6 N _ { A }$

  4. $ N _ { A }$

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Correct Option: A
Explanation:
$N^{3-}$ contains 10 electrons.

Number of moles $= \dfrac {4.2}{14} $
                                     
                                       $=0.3\ moles$

No of electrons in $0.3\ moles = 0.3\times N _A\times 10$

                                        $=3\ N _A$

Hence, option B is correct.

Mass of the one atom of the element X is $1.66 \times 10^{-26}$ g. Number of atoms in 1 g of the element is:

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $1.66 \times 10^{-26}$

  2. $1.66 \times 10^{25}$

  3. $1.66 \times 10^{-24} x No$

  4. $6.024 \times 10^{25}$

Show answer
Correct Option: D
Explanation:

Mass of one atom = $1.66 \times 10^{-26} g$
$1.66 \times 10^{-26} gm \rightarrow 1 \, atom$
$1 \, gm \rightarrow \dfrac{1}{1.66 \times 10^{-26}} $ atom
$= 6.024 \times 10^{25} atom$

Which of the following represents the Avogadro number?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Number of molecule present in 1 L of gas at N.T.P

  2. Number of molecule present in 22.4 L of gas at N.T.P

  3. Number of molecule present in 22.4 of gas at 298K and 1 atm pressure

  4. Number of molecule present in one mole of gas at any temp and pressure

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Correct Option: D

A vessel contains N molecules of oxygen at a certain temperature and pressure. How many molecules of sulphur dioxide can the vessel accommodate at the same temperature and pressure.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. N

  2. 2N

  3. N/2

  4. 4N

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Correct Option: A
Explanation:

As both have same volume and according to avagadro's law, equal volume of gases contains equal molecules so sulphur dioxide contains N molecules.

The gases chlorine, nitrogen, ammonia and sulphur dioxide are collected under the same conditions of temperature and pressure. If 20 litres of nitrogen contains 'x' no. of molecules, state the no. of molecules in 20 litres of ammonia.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. x

  2. x/2

  3. x/4

  4. 2x

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Correct Option: A
Explanation:

According to avagadro's law, equal volume of gases contains equal number of molecules. Therefore,  20 litres of ammonia will contain x number of molecule. 

A vessel contains X number of molecules of hydrogen gas at a certain temperature and pressure. Under the same conditions of temperature and pressure, how many molecules of nitrogen gas would be present in the same vessel?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. 2X

  2. X

  3. 0.5X

  4. 3X

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Correct Option: B
Explanation:

Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules" so same volume of nitrogen will have X number of molecules.

Statement: Equal volumes of all gases always contain equal number of moles.

State whether the given statement is true or false.
chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. True

  2. False

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Correct Option: A
Explanation:

 Avogadro law: It states that equal volumes of all gases under the same conditions of temperature and pressure contain the equal number of molecules. 

This means that as long as the temperature and pressure remain constant, the volume depends upon number of molecules of the gas.

Since volume of a gas is directly proportional to the number of moles; one mole of each gas at standard temperature and pressure (STP) will have same volume. 

Hence, the given statement is $\text{true}$

If $1$ L of $O _2$ at $15^oC$ and $750$ mm pressure contains $\text N$ molecules, the number of molecules in $2$ L of $SO _2$ under the same conditions of temperature and pressure will be :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $\dfrac {\text N}{2}$

  2. $\text N$

  3. $2\text N$

  4. $4\text N$

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Correct Option: C
Explanation:

Under similar conditions of temperature and pressure, equal volume of gas contains equal number of molecules.
$\therefore 1\ L=N$ molecules
$2\ L=2\ N$ molecules

Under the same conditions, two gases have the same number of molecules. They must:

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. be noble gases

  2. have equal volumes

  3. have a volume of 22.4 dm$^3$ each

  4. have an equal number of atoms

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Correct Option: B
Explanation:

Avogadro's hypothesis: Equal volume of all gases have equal number of molecules (not atoms) at same temperature and pressures conditions.

Four 1-1 litre flasks are separately filled with the gases $H _2,\, He,\, O _2$ and ozone. The ratio of total number of atoms of these gases present in different flask would be : 

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. 1 : 1 : 1 : 1

  2. 1 : 2 : 2 : 3

  3. 2 : 1 : 2 : 3

  4. 3 : 2 : 2 : 1

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Correct Option: C
Explanation:

According to Avogadro's law, all gases at same temperature and pressure will contain same number of molecules. Hence, number of molecules of all gases will be same bt ration of atoms of each gases will $2:1:2:3$.