Question

The compound As2I4 is synthesized by reaction of arsenic metal with arsenic triiodide. If a solid cubic block of arsenic (d = 5.72 g/cm3 ) that is 3.00 cm on edge is allowed to react with

1.01 * 10^24 molecules of arsenic triiodide, how much As2I4 can be prepared? If the percent yield of As2I4 was 75.6%, what mass of As2I4 was actually isolated?

Answer 1

Mass As₂I₄ actually isolated : 626.27 g

Further explanation

Reaction

2As+4AsI₃⇒3As₂I₄

mass As : ρ x V

`\tt 5.72* 3^3=5.72* 27=154.44~g`

mol As (MW 75 g/mol) :

`\tt (154.44)/(75)=2.059`

mol AsI₃ :

`\tt (1.01* 10^(24))/(6.02* 10^(23))=1.68`

Limiting reactant :

As:AsI₃ =

`\tt (2.059)/(2):(1.68)/(4)=1.03:0.42(AsI_3~smaller\rightarrow limiting~reactant)`

mol As₂I₄ :

`\tt (3)/(4)* 1.68=1.26`

mass As₂I₄ (Mw=657.461 g/mol)

`\tt 1.26* 657.461=828.4~g`

For 75.6% yield :

`\tt 0.756* 828.4=626.27~g`