100kg = 220.5 pounds.
mass is how much an object weighs. If you weigh 150 pounds, then you have a mass of 150 lbs (you can say pounds if you want instead of lbs, it is just the abbreviation for pounds). if you weigh 100 kilograms, then you have a mass of 100 kg( you can say kilograms or kilo's if you want, kg is just the abbreviation).
I would weigh 170 pounds. You would weigh 100 pounds on mercury but that has no effect on what I weigh.
About 38 pounds.
You would weigh about 91 pounds.
If you weighed 100 pounds on Earth you would then weigh 16.55 pounds (rounded) on the mercury