10. You demonstrated the difference in density of the two objects. It is a physical property.
11. First calculate the density for all of them: density = mass/volume
Density:
A. 5/6 g/ml
B. 10/9 g/ml
C. 15/16 g/ml
D. 20/10 g/ml
If the density of the substance is higher than the density of the substance it is put in, then it will sink. So substances B and D will sink in water, as their densities are higher than 1 g/ml.
12. Ammonia weighs less than water does-- for example, the weight of 8 gallons of ammonia will be equivalent to the weight of 5 gallons of water.
Hope this helped!