Hello! Let me try to answer this :)
Thanks and please correct if there are any mistakes ^ ^
I think the correct answer is option A. Pure substances can be considered as compounds. Compounds are molecules made of atoms from different elements held together by chemical bonds. Pure substances are these compounds that exist alone no other substance.
If I have 0.725 moles of gas at a temperature of 105 K and a pressure of 3.75 atmospheres the volume of the gas 1.66 litres.
Explanation:
Data given:
number of moles of the gas = 0.725
temperature = 105 K
pressure = 3.75 atm
volume of the gas =?
R = 0.08206 Latm/mole Kelvin
Applying the ideal gas law to calculate the volume of the given gas:
PV = nRT
rearranging the equation to calculate volume:
V = 
putting the values in the equation:
V = 
V = 1.66 Litres.
At a temperature of 105 K and pressure of 3.75 atm, 0.725 moles of gas occupy 1.66 litres of volume.
Basically, because the skater will never use some kind of a boost, they will rely purely on forces. At the top of a slope, their kinetic E is zero, and their Potential E is as high as it will be.
The skater will not be able to ever get higher that the initial height without some kind of force helping it.