   Question Answers

# The density of solid argon is 1.65 g per cc at -233$^{o}C$. If the argon atom is assumed to be a sphere of radius $1.54\times {{10}^{-8}}$cm, the percentage of empty space in solid argon is:(A )32%(B) 54%(C) 68%(D) 62%  Hint: The volume of one atom of Argon can be calculated by using the following formula.
Volume of one atom of Ar = $\dfrac{4}{3}\pi {{r}^{3}}$

-In the question it is given that the density of solid argon is 1.65 g per cc = 1.65 g/ml.
-Means 1.65 g of solid argon has 1 ml volume.
-We know that volume of one atom of Argon = $\dfrac{4}{3}\pi {{r}^{3}}\to (1)$
-We have to calculate the number of atoms in 1.65 g or in 1 ml of solid Argon
-To get the number of atoms we have to multiply the number of moles of argon with Avogadro number is as follows.
Number of atoms in 1.65 g of solid argon
\begin{align} & =\left( \dfrac{1.65}{40}mol \right)\left( 6.023\times {{10}^{23}} \right) \\ & =\dfrac{1.65\times 60.23\times {{10}^{23}}}{40} \\ \end{align}
-Now we have to substitute the number of atoms in 1.65 g of solid argon in equation (1) to get the total volume of all Argon atoms in 1 ml of Argon.
-Total volume of all Argon atoms in 1 ml of Argon = \begin{align} & =\dfrac{4}{3}\pi {{r}^{3}} \\ & =\dfrac{4}{3}\times \dfrac{22}{7}\times {{\left( 1.54\times {{10}^{-8}} \right)}^{3}}\times \dfrac{1.65\times 60.23\times {{10}^{23}}}{40} \\ & =0.380ml\text{ }or\text{ }0.380c{{m}^{3}} \\ \end{align}
-Given volume of solid Argon = 1 ml
-Therefore empty space = (1-0.380) ml = 0.620 ml.
-Therefore the percentage of empty space in empty Argon $=\dfrac{0.620}{1}\times 100=62%$
-The percentage of empty space present in solid Argon is 62%.

-So, the correct option is D.

Note: Don’t be confused with g per cc or g/ml. Both are the same.
We can measure the volume of any gas or solid by using g per cc or g/ml.
1 g per cc = 1 g/ml.

View Notes
The Solid State  Solid State Physics  Causes of Solid Waste Pollution  What is the full form of phd?  CBSE Class 8 Maths Chapter 10 - Visualising Solid Shapes Formulas  Value of g  States of Matter: Solid, Liquid, Gas  What is the Cell Envelope?  What is the Placebo Effect  What is the Difference Between Trade and Commerce?  Important Questions for CBSE Class 12 Chemistry Chapter 1 - The Solid State  NCERT Books Free Download for Class 12 Chemistry Chapter 1 - The Solid State  Important Questions for CBSE Class 12 Chemistry Chapter 7 - The p-Block Elements  Important Questions for CBSE Class 12 Chemistry Chapter 8 - The d and f Block Elements  Important Questions for CBSE Class 12 Chemistry  Important Questions for CBSE Class 12 Chemistry Chapter 5 - Surface Chemistry  Important Questions for CBSE Class 11 Chemistry Chapter 10 - The s-Block Elements  Important Questions for CBSE Class 11 Chemistry Chapter 11 - The p-Block Elements  Important Questions for CBSE Class 8 Maths Chapter 10 - Visualising Solid Shapes  Important Questions for CBSE Class 12 Chemistry Chapter 6 - General Principles and Processes of Isolation of Elements  Chemistry Question Paper for CBSE Class 12  CBSE Class 12 Chemistry Question Paper 2020  Chemistry Question Paper for CBSE Class 12 - 2013  Chemistry Question Paper for CBSE Class 12 - 2015  CBSE Class 12 Chemistry Question Paper 2019 - Free PDF  CBSE Class 12 Chemistry Question Paper 2017 - Free PDF  CBSE Class 12 Chemistry Question Paper 2018 - Free PDF  Previous Year Question Paper for CBSE Class 12 Chemistry - 2014  Chemistry Question Paper for CBSE Class 12 - 2016 Set 1 E  Chemistry Question Paper for CBSE Class 12 - 2016 Set 1 S  NCERT Solutions for Class 12 Chemistry Chapter 1  NCERT Solutions for Class 12 Chemistry Chapter 1 The Solid State in Hindi  NCERT Exemplar for Class 8 Maths Solutions Chapter 6 Visualising The Solid Shapes  NCERT Solutions for Class 7 Maths Chapter 15 Visualising Solid Shapes  NCERT Solutions for Class 8 Maths Chapter 10 Visualising Solid Shapes  NCERT Solutions for Class 12 English Kaliedoscope Poetry Chapter 6 The Wild Swans at Coole  Lakhmir Singh Chemistry Class 9 Solutions Chapter 4 - Structure Of The Atom  Surface Chemistry NCERT Solutions - Class 12 Chemistry  NCERT Solutions for Class 12 Chemistry Chapter 7 The p-Block Elements In Hindi  NCERT Solutions for Class 10 English First Flight Chapter 10 - The Sermon at Benares  