# Working with a First Order Rate Law

This page will present questions based upon first order processes, either radioactive decays or chemical reactions. When you press "New Problem", a question will apear to the right of the table. Obtain and submit the required answer. Results appear in the table. Use the "e" notation for presenting very large or small numbers. All masses are in **grams**, but the time dimension will vary.

- Read the question carefully. Sometimes you are asked about % or about the amount which has been consumed. In such cases, recall that the amount reacted,[]
_{r}=[]_{o}-[]_{t} - Be very careful about the time dimension as it changes occasionally.
- Percentage problems can be simplified by assuming a initial sample size of 100. The percentage given then becomes either []
_{r}or []_{t}, depending on the problem. - Pressing the "Show Answer" will cause the solution to appear and you will no longer be able to submit an answer for that problem.
- The solution is presented in what is viewed as the most error proof approach. It is certainly not the only method.