Question

1) Tungsten (W) reacts with Cl2 to form WCl6. What mass of WCl6 is formed from the reaction of 12.6 g W with 13.6 g Cl2?

2) NH3 reacts with O2 to produce NO and H2O. How many moles of O2 are needed to react with exactly 10.0 moles of NH3?

Answer 1

W + 3Cl2 ----> WCl6

this is the balanced reaction

one mole of W required 3 mole of Cl2

no of moles of W = weight of W / molar mass of W

= 12.6 / 183.84

= 0.0685 mol

n of mole of Cl2 = 13.6 / 70.9

= 0.2 moles

now 0.0685 moles required 3 x 0.0685 moles of Cl2 = 0.2 moles

0.0685 moles W will give 0.0685 moles WCl6

weight of WCl6 = no of moles of WCl6 x molar mass of WCl6

= 0.0685 x 396.6

= 27.17 grams will produce

2)

first write the balanced equation

4 NH₃ + 5 O₂ -----> 4 NO + 6 H₂O

from the equation it is clear that

4 mole of NH3 required 5 moles of O2

or

1 mole of NH3 required 5/4 moles of O2

similarly

10 mol of NH3 required 10 x 5/4 moles of O2

12.5 moles of O2 required