1) Ex. WATER + CO2 = BUBW

My proposal:

WATER + O2 = OZONE* + H2 ;)

2)COAL + FIRE = burning coal ;) and + ex. blue BIZR = blue flame of burning coal ;)Burning NITR also give blue flame ;)

3) You  can add also magnesium and phosphorous

4) I did write about this but i think that this is not bad idea :

Metallurgy :

Ex:

Iron + quartz = (after cooling) Iron resistance on high temperature (1000-2500 * C )

Iron + broken electronics =(--) Iron resistance on SPRK ;) (not conduct)

etc. ;)

* - the new element ;) (gas , not burn , cold etc.)