Which of these emits the most and which emits the least CO2?

Question

1. regular candle

2. colored candle

3. scented and colored candle

4. butane gas

Answer 1

The most would be number three,least being number four.

Answer 2

A candle is typically made of paraffin wax.  This is a long chain hydrocarbon, meaning that it's made up entirely of hydrogen and carbon.  When hydrocarbons burn, they give off water vapor and carbon dioxide.  Butane gas is also a hydrocarbon chain, but is only 4 carbon atoms long.  Paraffin is between 20 to 40 carbons long.  So butane gives off the least amount of CO2.  The most would come from probably a regular candle, because all the other stuff (scents and colors) are not pure hydrocarbons, but other complex molecules or even possibly inorganic pigment in the case of colors.  The scents are not burning like the wax, otherwise you wouldn't be able to smell it.

Answer 3

For the same amount of substance, from the most to least:

3 - 2 -1 -4

Just look at the amount of carbon atoms that is contained in every substance.

Answer 4

butane gas emits the least CO2.  this is because butane is C4H10.  when burned with O2 it produces relatively more H2O and less CO2.

wax is used in all three types of candle.  wax is like C40H82.  when burned with O2 it produces relatively more CO2 and less H2O  

i don't know if scent or color would affect CO2.  scent is likely an aromatic hydrocarbon but it displaces, by volume, a wax molecule.  scent and color are in such trace amounts it probably makes no difference.