Tag: avogadro hypothesis

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Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Assertion : 20 gm of argon (atomic mass of Ar $=40)$ occupies volume of $22400\ cm^3$ at STP.
Reason : 20 gm of Neon (atomic mass of $Ne=20$) occupies a volume of $22400\ cm^3$ at STP.

  1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

  2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

  3. Assertion is correct but Reason is incorrect.

  4. Assertion is incorrect but Reason is correct.

  5. Both assertion and reason are incorrect.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

20 g of argon is 0.5 moles and it occupies $(0.5\times 22400=)11200\ cm^3$ at STP.
20 g of Neon is 1 mole and occupies a volume of $22400\ cm^3$ at STP.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

According to Avogadro's hypothesis, equal volumes of gases under the same conditions of temperature and pressure will contain:

  1. the same number of molecules

  2. different number of molecules

  3. the same number of molecules only if their molecular masses are equal

  4. the same number of molecules if their densities are equal.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to avogadro's hypothesis, equal volumes of gases under the same conditions of temperature and pressure will contain, the same no. of molecules.

For eg. One volume of hydrogen combines with one volume of chlorine to produce two volumes of HCl gas.
$H _2\1vol$   $+$  $Cl _2=\1 vol$ $2HCl\2 vol$

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Which of the following statements is the most accurate with regard to the significance of Avogadro's number, $6.02 \times 10^{23}$ ?

  1. It is the conversion factor between grams and atomic mass units.

  2. It is a universal physical constant just as the speed of light.
  3. It is the number of particles that is required to fill a $1\ L$ container.
  4. It is the inverse diameter of an $H$ atom .
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A carbon atom weighs 12 AMU, one AMU is equivalent to $1.66 \times 10^{-24}$ grams. Conversely, one gram is equivalent to $6.022 \times 10^{23}$ AMU, which is called Avogadro's number


so the answer is A

Multiple choice chemistry atoms and molecules avogadro hypothesis avogadro's law avogadro law

At constant temperature, in a given mass of an ideal gas:

  1. the ratio of pressure and volume always remains constant

  2. volume always remains constant

  3. pressure always remains constant

  4. the product of pressure and volume always remains constant
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Boyle's Law states that, at constant temperature, the product of the pressure and volume of a given mass of an ideal gas in a closed system, is always constant.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

The critical volume of a gas is 0.036 $lit. mol^{-1}$. The radius of the molecule will be (in cm):
(Avogadro Number = $6 \times 10^{23}$)

  1. $\displaystyle \left( \frac{9}{4 \pi} \times 10^{-23} \right)^{\dfrac{1}{3}}$
  2. $\displaystyle \left( \frac{8 \pi}{3} \times 10^{-23} \right)^{\dfrac{1}{3}}$
  3. $\displaystyle \left( \frac{3}{8 \pi} \times 10^{-23} \right)^{\dfrac{1}{3}}$

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Critical volume of gas=3b [for 1 molecule]

For 1 mole, critical volume=0.036 liters
$\Longrightarrow 0.036\times { 10 }^{ 3 }{ cm }^{ 3 }=3\left( \cfrac { 4 }{ 3 } \pi { r }^{ 3 } \right) \times { N } _{ A } \ \Longrightarrow r={ \left( \cfrac { 36 }{ 24\pi  } \times 10^{ -23 } \right)  }^{ \cfrac { 1 }{ 3 }  }={ \left( \cfrac { 3 }{ 8\pi  } \times 10^{ -23 } \right)  }^{ \cfrac { 1 }{ 3 }  }$

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

The mass of a molecule of the compound $C {60}H _{122}$ is _________.

  1. $1.4\times 10^{-21}$ g
  2. $1.09\times 10^{-21}$ g
  3. $5.025\times 10^{23}$ g
  4. $16.023\times 10^{23}$ g
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Molecular mass of $C _{60}H _{122}=(60 \times 12+1 \times 122)=720+122=842$


Hence, one mole contains $6.022 \times 10^{23}$ molecules 


Therefore, 

Mass of one molecule $=\frac{842}{6.022 \times 10^{23}}$

$=1.4 \times 10^{-21}\;g$


The correct option is A.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

If you are given Avogadro's number of atoms of a gas $X$. If half of the atoms are converted into $X _{(g)}^+$ by energy $\Delta H$. The IE of $X$ is :

  1. $\dfrac{2\Delta H}{N _A}$
  2. $\dfrac{2N _A}{\Delta H}$
  3. $\dfrac{\Delta H}{2N _A}$
  4. $\dfrac{N _A}{\Delta H}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Given no. of atoms = Avogadro's no. of atoms = ${N} _{A} = 6.023 \times {10}^{23}$
Given that $\cfrac{{N} _{A}}{2}$ atoms are ionized, i.e.,
Ionization energy of $\cfrac{{N} _{A}}{2}$ atoms of gas X = $\Delta{H}$

$\therefore$ Ionization energy of 1 atom of gas X = $\cfrac{\Delta{H}}{\left( \cfrac{{N} _{A}}{2} \right)} = \cfrac{2. \Delta{H}}{{N} _{A}}$
Hence, Ionisation energy of gas X is $\cfrac{2. \Delta{H}}{{N} _{A}}$.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Assuming that the all volume is measured at the same temperature and pressure, state the volume ratios of the reactants and products for the following gaseous reactions. Nitrogen reacting with oxygen to form nitrogen (III) oxide.

  1. 1 : 3 : 2

  2. 2 : 4 : 2

  3. 2 : 2: 1

  4. 2 : 3 : 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The equation for the reaction between nitrogen and oxygen to form Nitrogen (lll) oxide is written as:
$2N _{2} + 3O _{2} \rightarrow 2N _{2}O _{3}$
Therefore the volume ratio of reactants and products $= 2 : 3 : 2$