A company compares two routes for making compound X.
| Route | Balanced equation | Percentage yield |
|---|---|---|
| P | 2A→2X+Y2A \rightarrow 2X + Y2A→2X+Y | 92% |
| Q | B+C→XB + C \rightarrow XB+C→X | 68% |
The relative formula masses are Mr M_r\,Mr of X = 75 and Mr M_r\,Mr of Y = 50.
Calculate the atom economy for making X by route P.
A student states, ‘Route P has a higher atom economy than route Q because its percentage yield is higher.’
Explain whether the student's statement is correct. Use the equations and the percentage yield data.
151 exam-style questions on Edexcel GCSE Chemistry 6.2 Quantitative analysis, covering 6.2.1 Concentration in mol dm⁻³ and titration calculations, 6.2.2 Percentage yield and why actual yield falls short, 6.2.3 Atom economy of a reaction, 6.2.4 Choosing a reaction pathway, and 6.2.5 Molar volume of gases and Avogadro's law. Each one has a worked solution and a mark scheme showing where the marks go.