allthebest Posted June 20, 2016 Report Share Posted June 20, 2016 QS: The rate expression for this reaction is rate = k [N2O]2 and the rate constant is 0.244 dm3 mol–1 s–1 at 750 °C. A sample of N2O of concentration 0.200 mol dm–3 is allowed to decompose. Calculate the rate when 10 % of the N2O has reacted. ANS: 0.9 × 0.200 = 0.180 (mol dm–3); rate = (0.244 × (0.180)2 =) 7.91 × 10–3 mol dm–3 s–1 Why do we have to times 0.9 to 0.200? I thought since 10% has reacted, 0.1 should be times instead of 0.9. Please help me clarify this question. Thanks alot Reply Link to post Share on other sites More sharing options...
kw0573 Posted June 20, 2016 Report Share Posted June 20, 2016 The concentrations used in rate calculation are how much are present. If 10% has been consumed then the concentration of N2O remaining is 90% of starting concentration. Reply Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.