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Density of a cubic crystal from its molar mass and unit cell data

This type of question, asked 8 times: May 2021 S1, May 2022 S1, 3 May 2023 S1, 10 May 2023 S2, 12 May 2024 S2, 14 May 2024 S2, 16 Apr 2026 S2, 20 Apr 2026 S1. All 9 questions below, oldest first.

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  1. Question 1

    May 2021 S1

    67
    At room temperature, polonium crystallises in a primitive cubic unit cell. If a=3.36 A˚a = 3.36\ \text{Å}, calculate the theoretical density of polonium. [Atomic weight = 209 g/mol]

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  2. Question 2

    May 2021 S1

    55
    What is the density of potassium if it has BCC structure with edge length 4 Å? (Atomic mass of K = 39)

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  3. Question 3

    May 2022 S1

    71
    Calculate the density of metal having volume of unit cell 64×10−2464 \times 10^{-24} cm3^3 and molar mass of metal 192 g mol−1^{-1} containing 4 particles in unit cell.

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  4. Question 4

    3 May 2023 S1

    53
    Calculate the density of an element having molar mass 63 g mol−163\ \text{g mol}^{-1} that forms fcc structure [a3×NA=28 cm3 mol−1a^3\times N_A=28\ \text{cm}^3\ \text{mol}^{-1}]

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  5. Question 5

    10 May 2023 S2

    87
    Calculate the density of a metal having molar mass 197 g mol−1197\,\text{g}\,\text{mol}^{-1} if it forms fcc structure. a3×NA=40 cm3 mol−1a^3 \times N_A = 40\,\text{cm}^3\,\text{mol}^{-1}

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  6. Question 6

    12 May 2024 S2

    74
    Calculate the density of an element having molar mass 2727 g mol⁻¹ that forms FCC unit cell. [a3NA=38.5a^3 N_A = 38.5 cm³ mol⁻¹]

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  7. Question 7

    14 May 2024 S2

    96
    Calculate the density of metal having molar mass 210 g mol−1210\,\text{g mol}^{-1} that forms simple cubic unit cell (a3⋅NA=21.5 cm3 mol−1a^3 \cdot N_A = 21.5\,\text{cm}^3\,\text{mol}^{-1})

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  8. Question 8

    16 Apr 2026 S2

    21
    When silver crystallizes, it forms face centered cubic cells, if the volume of unit cells 6.84×10−23 cm36.84 \times 10^{-23}\ \mathrm{cm^3}. Calculate the density of silver. (Molar mass of silver is 108 g/mol, NA=6.022×1023N_A = 6.022 \times 10^{23})

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  9. Question 9

    20 Apr 2026 S1

    22
    Calculate the density of an element having molar mass 225 g mol−1225\ \mathrm{g\,mol^{-1}} forming bcc structure [a3×NA=75 cm3mol−1][a^3 \times N_A = 75\ \mathrm{cm^3mol^{-1}}]

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