Question

how many moles of n2o5 are needed to produce 7.90 g of no2? 2n2o5→4no2 + o2

Explanation:

Step1: Calculate moles of \(NO_2\)

The molar mass of \(NO_2\) is \(M = 14+(2\times16)=46\space g/mol\).
Using the formula \(n=\frac{m}{M}\), where \(m = 7.90\space g\) and \(M = 46\space g/mol\), we have \(n_{NO_2}=\frac{7.90\space g}{46\space g/mol}\).

Step2: Use mole - ratio from the balanced equation

From the balanced equation \(2N_2O_5
ightarrow4NO_2 + O_2\), the mole - ratio of \(N_2O_5\) to \(NO_2\) is \(\frac{n_{N_2O_5}}{n_{NO_2}}=\frac{2}{4}=\frac{1}{2}\). So \(n_{N_2O_5}=\frac{1}{2}n_{NO_2}\).
Substitute \(n_{NO_2}=\frac{7.90}{46}\) into the equation: \(n_{N_2O_5}=\frac{1}{2}\times\frac{7.90}{46}\).

Answer:

\(n_{N_2O_5}=\frac{1}{2}\times\frac{7.90}{46}\approx0.0859\space mol\)