  Earth's atmosphere, on the other hand, is mostly nitrogen (78%) and oxygen (21%) with 1% being a mix of hydrogen, carbon dioxide and others. So you can see that Mars has much less atmosphere than the Earth does and oxygen make a proportionally much smaller fraction of of what there is than what we have on Earth.
Pickup trucks come in different shapes and sizes, and their weight entirely depends on the make and model. On average, a common pickup truck can weigh up to 3 tons, equivalent to 6,000 pounds.
3,000 lbs is more than enough for virtually all highway trucks unless they are capable of carrying more than 300 gallons of diesel, which most trucks are not able. We like to round off the weight of diesel fuel, just to make it easier. Use the round figure of 7 lb. per gallon, when calculating the weight.... One hundred gallons = 700 lbs. The weight of diesel does vary somewhat. It weighs a little more than 7 lb. per gallon in Canada, as the gallon is larger,