niche adsense website

I would like to create a website in a niche market for adsense. Keyword research has shown several highly searched terms (13k per month which I halved from Google results ). These keywords are available as domain names. The results show plenty of PPC ads.They are two word specific names. Is it worthwhile purchasing them and creating several sites or just have one domain name and optimize separate pages for the keywords? Hope this makes sense. Thank you

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