有关化学的英文题目(中英文回答都可以)

来源：百度知道 编辑：UC知道 时间：2024/06/20 11:35:31
1.If you started with 100 grams of a substance having a half-life of 2.5 hours,how much of the original substance would remain after 5 hours?7.5 hours?
2.If a radioactive substance has an extremely long half-life,would you expect its activity to be hogh or low?

1.半衰期问题。100g原物质，半衰期2.5h，5小时后就是100g*(1/2)^(5/2.5)=25g，7.5h后就是100g*(1/2)^(7.5/2.5)=12.5g

2.如果放射性物质有很长的半衰期，说明相对稳定，相应的活性就会比较低