10 lbs per sf.
Glass weighs 162 pounds per cubic foot. Tempering adds no weight. Glass is glass, except specialty glasses like high temperature glass, which weighs slightly more.
50kg
10Kilo
¼ kilo = 1¾ bags (2 x 1¾ = 3½), so 1 bag weighs 4/7 of a quarter kilo, ie 1/7 of a kilo.
An ounce is a measure of mass, not weight. A quarter weighs 6.4 ounce-weight.