A 1.000 g sample of copper reacts with an unknown element X to form 1.908 g...

A 1.000 g sample of copper reacts with an unknown element X to form 1.908 g Cu5X9. What is element X??

Solutions

Expert Solution

no of moles of Cu = W/G.A.Wt

= 1/63.546 = 0.015736 moles

5Cu(s) + 9X-------------> Cu5X9

5 moles of Cu react with excess of X to gives 1 mole of Cu5X9

0.015736moles of Cu react with excess of X to gives = 1*0.015736/5 = 0.0031472moles fo Cu5X9

molar mass of Cu5X9 = mass of Cu5X9/no of moles

= 1.908/0.0031472 = 606.25g/mole

9 atoms molar mass of X = molar mass of Cu5X9- atomic mass of Cu

= 606.25-5*63.546

= 288.52

atomic mass of X = 288.52/9 = 32.06g/mole

The unknown element X is sulfur

sulfur >>>>answer

queen_honey_blossom answered 1 month ago

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