Chemical container sent up with speed (7)
I believe the answer is:
nitrate
'chemical' is the definition.
(I've seen this before)
'container sent up with speed' is the wordplay.
'container' becomes 'tin' (tin is a kind of container).
'sent up' is a reversal indicator.
'with' is a charade indicator (letters next to each other).
'speed' becomes 'rate' (the speed at which something happens).
'tin' backwards is 'nit'.
'nit'+'rate'='NITRATE'
(Other definitions for nitrate that I've seen before include "Compound" , "following 28 [SILVER]" , "Tear tin up for fertiliser" , "Natural or synthetic fertiliser" , "Fertilizer" .)