I think this what you're looking for http://www.webmd.com/oral-health/salivary-glands
Answer:
Molecular mass, 
Explanation:
Given that,
Mass of gas, m = 0.46 g
Volume of the container, V = 515 cm^3
Pressure, P = 153 kPa
Temperature, T = 322 K
We need to find the molecular mass of this gas. We know that,
PV =nRT
n = no of moles

No of moles = mass/molecular mass
Let molecular mass is M

So, the molecular mass of this gas is 
Answer:
The oxidation number of the metal decreases
2 Al + Fe₂O₃ → Al₂O₃ + 2 FeO
The metal element iron, is reduced from Fe⁺³ in Fe₂O₃ to Fe⁺² in FeO
Explanation:
When an element gains electron, the element becomes reduced, hence when a metal is reduced, the metal gains electrons, which reduces the oxidation number of the metal
An example of a metal being reduced is;
2 Al + Fe₂O₃ → Al₂O₃ + 2 FeO
In the above reaction, the iron (III) oxide is reduced to iron (II) oxide by aluminium metal.
The answer would be Biased. I am not 100 percent sure but I really hope that helps.