Answer:
The mass density will be doubled
Explanation:
- Density is given by dividing the mass of a substance by its volume.
- An increase in mass causes an increase in density and vice versa, while a decrease in volume causes an increase in density and volume.
- Therefore, when the volume is halved, then the density will be doubled if the mass is kept constant.
- This has no effect on the number of moles as the mass is constant.
Answer: Ice is melting due to the transfer of thermal energy from Jan's hand to ice.
Explanation: The melting of ice is a physical change and is happening when the thermal energy from Jan's hand is transferred to ice. Due to this energy transfer, the particles of ice starts to move faster and hence, making the ice melt.
In this, the physical state of ice is changing from solid to liquid state.

Answer:
Hydrogen, H_2
Explanation:
mass of each gas is 10.0 g
number of mole = mass/ molar mass
number of moles is directly proportional to volume at constant temp and pressure
this implies that the volume is inversely proportional to molar mass. And Among all the gases in periodic table the molar mass of Hydrogen is the least.
molar mass of H2=2 g/mol
Since, H2 has minimum molar mass then for the same mass of the gases Hydrogen will have maximum volume.
Answer:
The plane with aluminium can lift more mass of passangers than the plane of steel.
Explanation:
The total mass the airplane canc lift is:

For aluminium:


and
![V_{fuselage}=\frac{\pi *L}{4}*[D^2-(D-e)^2]](https://tex.z-dn.net/?f=V_%7Bfuselage%7D%3D%5Cfrac%7B%5Cpi%20%2AL%7D%7B4%7D%2A%5BD%5E2-%28D-e%29%5E2%5D)
where:
- L is lenght
- D is diameter
- e is thickness
![m_{tot}=\delta _{Al}*\frac{\pi *L}{4}*[D^2-(D-e)^2]+m_{pas-Al}](https://tex.z-dn.net/?f=m_%7Btot%7D%3D%5Cdelta%20_%7BAl%7D%2A%5Cfrac%7B%5Cpi%20%2AL%7D%7B4%7D%2A%5BD%5E2-%28D-e%29%5E2%5D%2Bm_%7Bpas-Al%7D)
For steel (same procedure):
![m_{tot}=\delta _{Steel}*\frac{\pi *L}{4}*[D^2-(D-e)^2]+m_{pas-Steel](https://tex.z-dn.net/?f=m_%7Btot%7D%3D%5Cdelta%20_%7BSteel%7D%2A%5Cfrac%7B%5Cpi%20%2AL%7D%7B4%7D%2A%5BD%5E2-%28D-e%29%5E2%5D%2Bm_%7Bpas-Steel)
Knowing that the total mass the airplane can lift is constant and that aluminum has a lower density than the steel, we can afirm that the plane with aluminium can lift more mass of passangers.
Also you can estimate an average weight of passanger to estimate a number of passangers it can lift.