有关化学的英文题目(中英文回答都可以)1.Ifyoustartedwith100gramsofasubstancehavingahalf-lifeof2.5hours,howmuchoftheoriginalsubstancewouldremainafter5hours?7.5hours?2.Ifaradioactivesubstancehasanextremely

Question

有关化学的英文题目(中英文回答都可以)
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?

Answer 1

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