(a) what is a hydrocarbon ? (b ) pentane is the alkane with a chain of five carbon atoms. write a structural formula for this compound and determine its molecular and empirical formulas.

The modern periodic table has groups.

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?