First i am a bit new to adsense , i wanted to know if anyone can give me an approximation how much i can earn through Adsense if a keyword is searched 50000 times , and i am ranked first for this KW ... Also if the adsense ads are perfectly placed in order to tempt people to click .. can 50000 unique visitors/month to a site result in $500 / month ?
It all depends on the keyword. Some keywords pay a couple of cents, some pay dollars. The type of traffic can also affect CTR. Repeat visitors to a forum tend to become "ad blind" and can produce very low click through rates. Some niche sectors can have a CTR of over 50%. There are so many factors involved that it would be impossible to give you an accurate figure. It's entirely "possilbe".
Impossible to tell as others have opined. I added adsense ads to my blog a week ago and it appears I will earn considerably less than the total you hope to achieve. Considerably less! I average 27000 uniques a month.
With a CTR of 5%/visit (eg. average page views:2, average page CTR:2.5%) and an average of 0.1$ you achieved it. So I think you're goal is fairly achievable considering a niche with moderate competition. If the competition is big, you may get a lot more.
How can i find if the keywords of my website are payed well? By the number of advertiser? More = higher pay/click?
thats a good guess.. the more competition the more they will pay But you can also login to your adwords account and see what the actual average cost per click for a keyword is.
This tool helps you find how many times a keyword is search in a month. http://inventory.overture.com/ Regards.
Usually blog sites are having lower Page CTR% than content sites. Consider reading Google adsense help on heat map