A 3m41s vid on Endothermic & Exothermic Reactions (Bitesize Top 20 Demos):
Science Bank (Reactions & Energy Changes): part 1 – exothermic & endothermic reactions (just the first 4m 40s):
BBC Short Circuit Energy Changes – a 19m video.
GCSE Bitesize has revision pages (that take you through the topic), a test and an activity, just scroll down to Exothermic & Endothermic Reactions.
GCSE s-cool – electrolysis includes Energy Changes in chemical reactions – revision notes & animations.
For Doc Brown’s Chemistry quizzes, word-fills, crosswords and study notes go here and just scroll down.