Since the configuration contains the number 2s and 2p, you can assume that it is in period 2 of the periodic table. By noble gas shorthand, you start with helium, which is atomic number 2. 2s²2p^4 has 2+4 = 6 valence
Add 2+6 = 8, which is Oxygen.
One Nitrogen and three iodine's react to form two nitrogen triiodides.
M(O)= 16 g/mol
M(H)=1 g/mol
m(O)/m(substance)
1) 16/17
2)16/18
3) 16/19
4) 32/34=16/17
1) and 4) give the same answers, and 16/17 are the greatest fraction, so greatest % oxygen by mass also.
The answers should be 1) and 4).
Answer:
100g/mol
Explanation:
Given parameters:
Mass of unknown gas = 2g
Volume of gas in flask = 500mL = 0.5dm³
Unknown:
Molar mass of gas = ?
Solution:
Since we know the gas is at STP;
1 mole of substance occupies 22.4dm³ of space at STP
Therefore,
0.5dm³ will have 0.02mole at STP
Now;
Number of moles =
Molar mass = = = 100g/mol