Tag: avogadro law

Questions Related to avogadro law

The number of gram molecule of oxygen in $6.02 \times 10^{24}$ CO molecules is :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. 10 gm molecules

  2. 5 gm molecules

  3. 1 gm molecules

  4. 0.5 gm molecules

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Correct Option: B
Explanation:

Given :


$6.02\times 10^{24}$ $CO$ molecules


We know,

$1$ mole $CO$ equivalent to $6.023\times 10^{23}$ molecules of $CO$

$6.023\times 10^{23}$ molecules of $CO$ contain $6.023\times 10^{23}$ atoms of $O$

Then, $6.02\times 10^{24}$ $CO$ molecules contain $6.02\times 10^{24}$ atoms of $O$

$\Rightarrow$ no. of gram atoms of $O=\cfrac {6.02\times 10^{24}}{6.02\times 10^{23}}$

$=10gm$ atoms  $\longrightarrow 1$

As oxygen is a diatomic molecule.

No. of gm of molecules of oxygen=$\cfrac {10gm\quad atoms}{2\quad atoms/molecule}=5gm$ molecules

Therefore, the correct option is B.

The number of g-atom of oxygen in $6.02\times { 10 }^{ 24 }$ $CO$ molecule is

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $1$

  2. $0.5$

  3. $5$

  4. $10$

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Correct Option: D
Explanation:

One molecule of $CO$ contains one oxygen atom
$\therefore 6.02\times { 10 }^{ 24 }\quad $ molecules of $CO$ contain $6.02\times { 10 }^{ 24 }$ oxygen atoms
$6.02\times { 10 }^{ 23 }$ atoms of oxygen $\equiv$ $1g$ atom of oxygen
$\therefore 6.02\times { 10 }^{ 24 }$ atoms of oxygen $\equiv$ $10g$ atom of oxygen.

At room temperature and pressure, two flasks of equal volumes are filled with $H _2$ and $SO _2$ separately. Particles which are equal in number, in the two flasks are:

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. atoms

  2. electrons

  3. molecules

  4. neutrons

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Correct Option: C
Explanation:

At a given volume at constant temperature and pressure, two gases have equal no. of moles 

hence, the no. of molecules will be same in both flasks.

Which of the following statement about Avogadro's hypothesis is correct?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Under similar conditions of temperature and pressure, gases react with each other in simple ratio.

  2. Under similar conditions of temperature and pressure, equal volumes of all gases contain same number of molecules

  3. At NTP all gases contain same number of molecules

  4. Gases always react with gases only at the given temperature and pressure

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Correct Option: B
Explanation:

Avogadro’s Law states that under same conditions of temperature and pressure, equal volume of all the gases contain equal number of molecules.

The molecular weights of $O _2$ and $N _2$ are $32$ and $28$ respectively. At $15^0$C, the pressure of $1$gm $O _2$ will be the same as that of $1$ gm $N _2$ in the same bottle at the temperature:

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $-21^0$C

  2. $-13^0$C

  3. $15^0$C

  4. $56.4^0$V

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Correct Option: B
Explanation:
Temperature of $O _{2}$ $=273+15=298 K$

Temperature of $N _{2}$ $=x$

As $n$ $\propto$ $\dfrac 1T$, as pressure is constant.

$\Longrightarrow { n } _{ 1 }{ T } _{ 1 }={ n } _{ 2 }{ T } _{ 2 }\Longrightarrow \left( \cfrac { 1 }{ 32 }  \right) \left( 298 \right) =\left( \cfrac { 1 }{ 28 }  \right) \left( x \right) \\ \Longrightarrow x=\cfrac { 28 }{ 32 } \times 298=260.75K$

Temperature in $^oC=260.75-273=-13 ^oC$

Hence, option $B$ is correct.

When 4 l of nitrogen completely reacts with hydrogen, what would be the volume of ammonia gas formed?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. 2 l

  2. 4 l

  3. 5 l

  4. 8 l

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Correct Option: D
Explanation:

Reaction:
$N _2+3H _2  \rightarrow 2NH _3$
 1     3               2
so 4 litre of nitrogen will produce 8 litre of $NH _3$

Gram molar volume for a gas is always considered at ___ conditions.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. NTP

  2. STP

  3. variable temperature

  4. none of these

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Correct Option: B
Explanation:

Since volume is a dependent variable and it depends on pressure and temperature always so temperature and pressure should be specified when volume of gas is considered. For this certain standard conditions are taken as 273 K and 1 atm pressure.
And at STP, molar volume is 22.4 litre.

Two gases A and B are taken in same volume containers under similar conditions of temperature and pressure. In container A, there are '2N' molecules of gas A. The number molecules does container B have :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. N

  2. 0.5N

  3. 2N

  4. 4N

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Correct Option: C
Explanation:
1. According to Avogadro's law, the equal volume of gases under a similar condition of pressure and temperature contain equal no. of molecules. 
Therefore the number of molecules in container B will also be 2N.

2. As we know, one mole of each gas occupies 22.4-litre volume and one mole of gas contains NA molecules at STP.

So at the same temperature and pressure, the equal volume of gas contains equal no of molecules.

Therefore the number of molecules in container B will also be 2N.

Therefore, the option is C.

Which scientist discovered that the same amount of space was occupied by equal numbers of molecules of gases, irrespective of whether it was hydrogen or chlorine or fluorine?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Gay-Lussac

  2. Avogadro

  3. Marconi

  4. Wohler

Show answer
Correct Option: B
Explanation:

Avogadro first discovered it.
It states that $1$ $mole$ of any element or compound have $6.022\times 10^{23}$ atoms or molecules present at any constant temperature and pressure.

When a certain quantity of oxygen was ozonised in suitable apparatus, the volume decreased by $4\ ml$. On addition of turpentine the volume further decreased by $8\ ml$. All volumes were measured at the same temperature and pressure. From these data, establish the formula of ozone.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $\displaystyle :O _{3}$

  2. $\displaystyle :O _{4}$

  3. $\displaystyle :O _{5}$

  4. $\displaystyle :O _{6.5}$

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Correct Option: A
Explanation:

Let the formula of ozone be $\displaystyle O _n $
When a certain quantity of oxygen was ozonised in suitable apparatus, the volume decreased by 4 ml.
$\displaystyle  nO _2 \rightleftharpoons 2O _n $
$\displaystyle n-2 \propto 4 $
On addition of turpentine the volume further decreased by 8ml. All volumes were measured at the same temperature and pressure.
$\displaystyle  8mL = 2\times 4mL $
$\displaystyle 2=2n-4 $
$\displaystyle 6=2n $
$\displaystyle  n=3$
Thus, the formula of ozone is $\displaystyle O _3 $.