Nitrosyl bromide decomposes according to the following equation. 2NOBr (g) 2NO (g) + Br₂ (g)
A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br₂. At equilibrium the flask contained 0.36 mol of NOBr. How many moles of NO and Br₂, respectively, are in the flask at equilibrium?

Question

Nitrosyl bromide decomposes according to the following equation. 2NOBr (g)

2NO (g) + Br₂ (g)
A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br₂. At equilibrium the flask contained 0.36 mol of NOBr. How many moles of NO and Br₂, respectively, are in the flask at equilibrium?

Quizplus · Accepted Answer

From the balanced equation, we can see that for every 2 moles of NOBr that decompose, 2 moles of NO and 1 mole of Br2 are produced. Therefore, if x moles of NOBr decompose, then there will be 2x moles of NO and x moles of Br2 at equilibrium. 
We know that 0.64 mol of NOBr was initially placed in the flask, and 0.36 mol is left at equilibrium. This means that 0.28 mol of NOBr has decomposed, resulting in the formation of 2(0.28) = 0.56 mol of NO and 0.28 mol of Br2. Therefore, the number of moles of NO and Br2 in the flask at equilibrium are 0.56 mol and 0.28 mol, respectively. Thus, the answer is (C) 0.28, 0.14.

Nitrosyl Bromide Decomposes According to the Following Equation