I think it is 3 because Sus wiw word if rn
        
             
        
        
        
Answer:
Don't post any question if isn't related to the topic or to your homework or assignment. 
Explanation:
 
        
             
        
        
        
Answer: 97
Explanation:
The element Ru is <u>Ruthenium</u> which has <u>44 protons</u>.
In this case, our atom is an isotope with <u>53 neutrons</u>.
With this information, we can use the mass number formula to find this atom's mass number.
mass number = protons + neutrons
mass number = <u>44 protons</u> + <u>53 neutrons</u>
mass number = <u>97</u>
 
        
             
        
        
        
Answer: The molar mass of each gas 
Explanation:
Mole fraction is the ratio of moles of that component to the total moles of solution. Moles of solute is the ratio of given mass to the molar mass.

Suppose if there are three gases A, B and C.
a) 
b) 
c) 
moles of solute =
Thus if mass of each gas is known , we must know the molar mass of each gas to know the moles of each gas.