yes
Cobustible substances can catch on fire but non-combustible substances are inflammabe
Technically speaking, sulfur (note that it does NOT begin with a capital unless it is the first word in a sentence) is correct. 'Sulfur' is the international chemical term recommended by IUPAC...
33% because sulphur dioxyde is composed of two oxygen atoms and one of sulphur.
Oxygen is always 2-, so to balance the molecule SO2 the sulphur here must be 4+.
Sulfur.