Prior to their phaseout in the 1980s, chemicals containing lead were commonly added to gasoline as anti‑knocking agents. a 7.031 g sample of one such additive containing only lead, carbon, and hydrogen was burned in an oxygen‑rich environment. the products of the combustion were 7.653 g co2(g) and 3.916 g h2o(g) .

Covalent bonds generally form when the bonded elements have a difference in electronegativity less than 1.5. subtract the electronegativities for the following pairs of elements and predict whether they form a covalent bond. electronegativity difference of c and c: ionic covalent electronegativity difference of mg and cl: ionic covalent