One quart of oil = 1.88 pounds The viscosity of the oil has no bearing on actual weight.
Oil will float in water, so the water weighs more.
A quart of cream will weigh as 0.64 in lbs
One quart of Mobil Special 10W-40 motor oil weighs 1.8 pounds. Not all motor oils have the same density, and one gallon of motor oil will weigh between 6 and 8 pounds.
It depends on the liquid - one quart of mercury is going to weigh much more the one quart of water. Refine your question.
A quart of oats weighs approximately one pound.
1 quart (0.946 litres or 0.946 kilograms)
About 2.08 lbs.