What do all the atomic models have in common?

If you add 10ml of hot water to 10ml of cold water and the change in tempature 8°c calculate how much energy is gained by the cold water

How many grams of ammonia would be produced by the decomposition of 16.93 mlof hydrazine? (the density of hydrazine is 1.021g/ml)

The solubility of barium nitrate is 9.02 g/100 g h2o at 20°c. a 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°c. is the solution saturated, unsaturated, or supersaturated? a. unsaturated b. saturated c. supersaturated