How much concrete is in 1 square meter?

Answer 1

If you mean volume you need the thickness as well. You've quoted only area.

Then if you mean mass, you'd need the density too.

I suspect you meant to ask about the weight of 1 cubic meter of cement. Quoting directly from the source given below: "The unit weight of concrete (density) varies depending on the amount and density of the aggregate, the amount of entrained air (and entrapped air), and the water and cement content. A normal weight concrete weighs 2400 kg per cubic meter or 145 lbs per cubic foot (3915 lbs per cubic yard)."