The word participates 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: 21
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (60 words)
acaters, airiest, airpipe, apatite, appears, apprise, apteria, artiest, aseptic, atresia, attires, carpets, cattier, citrate, crappie, cristae, epicarp, icespar, iratest, irisate, parapet, parties, pastier, patters, patties, piarist, picrate, picrite, pietist, pirates, pitiers, precast, priapic, raciest, sappier, satiate, satiric, scatter, spacier, spatter, spectra, spicate, spicier, spiraea, statice, stipite, striate, tappers, tapster, tastier, teacart, tipcart, tipcats, tippers, tippier, tipsier, tipster, traipse, triceps, trisect