A physical change is when something don't permanently change
The notion <span>an empty balloon have precisely the same apparent weight on a scale as a balloon filled with air depends on the diameter of the balloon. The weight of the balloon filled with air is equal to the mass of the balloon and the mass of the air inside. The mass of air inside is equal to the density of air multiplied by the volume of the balloon. If the balloon is large, then the two masses are equal whereas if not, the mass of air inside the inflation is neglible</span>
1. There are 41.99 grams in 4.5 moles of sodium fluoride.
2. There are 1.26 moles in 98.3 grams of aluminum hydroxide.
3. There are 5 grams in 0.02 moles of beryllium iodide.
4. There are 0.70 moles in 68 grams of copper (II) hydroxide.
5. There are 0.064 grams in 2.3x10^-4 moles of calcium phosphate.
The unknown medium would be glass
