Sorry to be pedantic guys.. BUT I found this to backup my earlier statement
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It can readily be shown by calculation that the efficient burning of a gallon of (nonane-based) petrol in a car engine produces slightly less than eight pints of water (as well as nearly 6000 litres of carbon dioxide); and that a gallon of (cetane-based) diesel produces slightly more than nine pints of water (and slightly more than 6000 litres of carbon dioxide).
• For Nonane-based petrol:
C9H20 + 14 O2 = 10 H2O + 9 CO2
• For Cetane-based DERV:
C14H30 + (43/2) O2 = 15 H2O + 14 CO2
Constants and Conversion Factors
• The density of nonane-based petrol is taken to be 740 gm/litre (740 gm/1000 cc);
• The density of cetane-based DERV is taken to be 835 gm/litre (835 gm/1000cc);
• The density of water is taken to be 1000 gm/litre;
• One gram-mole (Gram Molecular Weight) of any gas occupies 22.4 litres of volume at Standard Temperature and Pressure;
• One Imperial gallon is equivalent to 4.546 litres;
• One Imperial pint is equivalent to 0.56825 litres.
The amounts of water generated in this way are not trivial. It can readily be shown by calculation that the efficient burning of a gallon of (nonane-based) petrol in a car engine produces slightly less than eight pints of 'new' water (as well as nearly 6000 litres of carbon dioxide); and that a gallon of (cetane-based) diesel produces slightly more than nine pints of water (and slightly more than 6000 litres of carbon dioxide).
• Estimated annual world production of crude oil last year was 30 billion barrels. 30-40 per cent of crude can be catalytically cracked into lighter fractions for use as liquid fuel in various types of internal combustion engine.
• Taking those numbers as a very rough guide, the implication is that we threw somewhere in the region of ten to twelve billion barrels of 'new' water into the environment last year, simply for the sake of running our vehicles and power-stations. 6.2897 barrels = one cubic meter: 10 billion barrels is 1,589,900,949 cubic metres: one cubic metre of water weighs one tonne: we therefore threw somewhere in the region of 1.6 billion metric tons of new water into the oceans last year - without even realising that we'd done it. This new water will certainly affect the salinity of the oceans as well, to some extent.