Answer: PV = nRT
A gas at STP... This means that the temperature is 0°C and pressure is 1 atm.
R is the gas constant which is 0.08206 L*atm/(K*mol)
Rearranging for volume
V = nRT/P
The temperature and number of moles are held constant. This means that this uses Boyle's Law. (The ideal gas law could be manipulated to give us this result when T and n are held constant.)
PV = k
where k is a constant.
This means that
P₁V₁ = k = P₂V₂
P₁V₁ = P₂V₂
(1 atm) * (1 L) = (2 atm) * V₂
V₂ = 0.5 L
The new volume of the gas is 0.5 L.
Explanation:
 
        
             
        
        
        
A) covert 0.330g to moles by dividing by molar mass of P2O5 .. Let's call this Y moles 
B) 1 mole of anything contains the Avogradro Number of molecules 
So here it is 6.02 x 10^23 x Y molecules 
C) work out how many atoms in each molecule 2P + 5O total 7 
So multiply answer to B by 7 to get final answer
        
             
        
        
        
Answer: The average valence electron energy (AVEE) of this element =
1014.2 KJ/ mol  or  1.0142mJ/mol.
Explanation:
The average valence electron energy =  (number of electrons in s subshell  x  Ionization energy of that subshell) + (number of electrons in p subshell  x  Ionization energy of that subshell) / total number of electrons in both subshells of the valence shells.
 The 5A elements are non-metals like Nitrogen and Phosphorus with the metallic character increasing as you go down the group, So a new 5A element will have characteristics of its group with 5 valence electron in its outermost shell represented as ns2 np3
Therefore  the average valence electron energy (AVEE) of this element will be calculated as 
 The average valence electron energy = (2 x 1370  kJ/mol + 3 x 777 kJ/mol.) / 5 
2740+2331/ 5 =5071/5
=1014.2 KJ/ mol  or  1.0142mJ/mol.
 
        
             
        
        
        
Condensation occurs through the release of energy
        
             
        
        
        
Answer:
This element is Rubidium (Rb) and has an average atomic mass of 85.468 u 
Explanation:
The average mass of an element is calculated by taking the average of the atomic masses of its stable isotopes.
The enitre atomic mass = 100 % or 1 
⇒ this consists of X-85 with 72.17 % abundance  with atomic massof  84.9118 g/mol
72.17 % = 0.7217
⇒ this consists of X-87 with  27.83 % abundance with atomic mass of 86.9092 g/mol
27.83 % = 0.2783 
To calculate the mass of this isotope we use the following:
0.7271 * 84.9118 + 0.2783 * 86.9092 =85.468 g/mol
 This element is Rubidium(Rb) and has an average atomic mass of 85.468 u