An alloy has a Cu 2 Pt 1 composition. Assume that this alloy has a fcc unit cell with an edge length of 380 pm , but the Cu and Pt atoms are randomly distributed in the atomic positions. Calculate

Question

An alloy has a Cu 2 ​ Pt 1 ​ composition. Assume that this alloy has a fcc unit cell with an edge length of 380 pm , but the Cu and Pt atoms are randomly distributed in the atomic positions. Calculate the density of this alloy in g / cm 3 . (Report your answer to nearest integer) Atomic mass of Cu and Pt are 63.54 and 195.1 respectively

TestHub · Accepted Answer

Actual unit cell composition: Cu 2.66 ​ Pt 1.33 ​ V a V d ​ = a 3 = 380 pm = 3.80 × 1 0 − 8 cm = ( 3.80 × 1 0 − 8 ) 3 = 54.87 × 1 0 − 24 cm 3 = V m ​ = 54.87 × 1 0 − 24 cm 3 [ 2.66 × ( A w ​ ( Cu )) + 1.33 × ( A w ​ ( Pt ))] / N A ​ ​ = 54.87 × 1 0 − 24 [ 2.66 × ( 63.54 ) + ( 195.1 ) × 1.33 ] /6.02 × 1 0 23 ​ = 12.97 g / cm 3 ​

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