Question

Find the number of unit cells in 117 gram of NaCl

Answer 1

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MARK ME BRAINLIEST ✌✌✌

Answer 2

Given: mass of NaCl - m = 117g

To Find: number of unit cells in 117 grams of NaCl

Solution:

Concept and Formula used:

• NaCl Lattice exits in FCC arrangement.

• Hence 1 unit consists of 4 molecules of NaCl
• Molecular mass of NaCl = 23 + 35.5 = 58.5g
• Number of moles - n = Given mass(m)/molecular mass(M)
• Number of moles (n) = given number of molecules(N)/Avagadro number (Nₐ) Nₐ = 6.023 × 10²³

Applying the above formula to calculate the number of moles of NaCl:-

n = m/M

n = 117g/58.5g

n = 2 moles of NaCl

• 1 unit cell of NaCl has = 4 molecules of NaCl

• Calculate number of molecules in 2 moles of NaCl by using the given formula above:-

n = N/Nₐ

N = n × Nₐ

N = 2 × 6.023 × 10²³

N = 12.046 × 10²³

1 unit cell of NaCl has = 4 molecules of NaCl

number of unit cells with 12.046 × 10²³ molecules of NaCl

number of unit cells with 12.046 × 10²³ molecules of NaCl = 12.046 × 10²³/4

The Number of unit cells = 3.01 × 10²³