physical change
particles retain there composition and identity
there is no change in there chemical properties of the substance
the chemical changes should be the other two.
If it is wrong I'm truly sorry.
Answer:
4.525% is the percentage by volume of oxygen in the gas mixture.
Explanation:
Total pressure of the mixture = p = 4.42 atm
Partial pressure of the oxygen = 
Partial pressure of the helium = 
(Dalton law of partial pressure)





According Avogadro law:
(At temperature and pressure)
Volume occupied by oxygen gas =
Total moles of gases = n = 1 mol
Total Volume of the gases = V


Percent by volume of oxygen in the gas mixture:

I think the best answer would be D. Dolphin!
Hey there!
Density = 2.70 g/cm³
Volume = 10.0 cm³
Therefore:
Mass = density * volume
Mass = 2.70 * 10.0
Mass = 27.0 g