There is ! You may approach to high paying ads, but might not get that exact amount. For sure your earnings will increase, which is most important
Yes you can see worth of a keyword in google external keyword tool , but while using adsense you will not get exactly that amount as a publisher.But only a portion of that which is paid by advertiser.
Use the Google keyword external tool and it will display the cost that advertisers pay for a certain keyword and this is a free tool. you can use other paid tools which will display the cost too but it may cost you a bit of money. Thanks JulieV