The word chimneysweeps is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 30
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (28 words)
cephems, cheeses, chimney, enemies, epicene, eschews, essence, hipness, mispens, misween, nemesis, nephews, nymphic, penises, pheeses, physics, pinches, psyches, schemes, shipmen, siemens, species, sphenes, sphenic, wenches, whimsey, winches, wisemen