Answer:
Gas X
Explanation:
The given reaction can be written in the form of chemical equation as shown below as:
According to law of conservation of mass, the moles of each substance in the reaction must be equal on both reactant and product side.
Also, the question asks for the gas which is diatomic. 
cannot be diatomic as the formula contains 3 atoms.
Between gas X and gas Y , <u>X has to be diatomic for the reaction to balance </u>as:
98 elements are naturally forming elements.
Answer: 98
Answer: The pressure of the He is 2.97 atm
Explanation:
According to Dalton's law, the total pressure is the sum of individual pressures.
Given : 
=total pressure of gases = 6.50 atm
= partial pressure of Nitrogen = 1.23 atm
= partial pressure of oxygen = 2.3 atm
= partial pressure of Helium = ?
putting in the values we get:
The pressure of the He is 2.97 atm
From ideal gas equation that is PV=nRT
n(number of moles)=PV/RT
P=760 torr
V=4.50L
R(gas constant =62.363667torr/l/mol
T=273 +273=298k
n is therefore (760torr x4.50L) /62.36367 torr/L/mol x298k =0.184moles
the molar mass of NO2 is 46 therefore density= 0.184 x 46=8.464g/l
