Assertion: motor oil | /r/HasProperty | exposed to oxygen
Facets:
value: during engine combustion
type: TEMPORAL
value: in the presence of considerable heat
type: TEMPORAL
Source sentences:
text: Since motor oil invariably contains some chemical "unsaturation" — carbon-to-carbon double or triple bonds — and is exposed to oxygen in the presence of considerable heat, oxidation occurs to form carboxylic acid, which attacks metal.
text: Motor oil is exposed to heat and oxygen during engine combustion, which changes its chemical makeup.