Your protons are correct but it’s 28 neutrons not 27!
The equation for this question could be 
→
.
so for 6.75 moles of 
*3 moles of O_{2}/2 moles of
= 10.125
Answer:
Option A
Explanation:
Standard molar entropy determines the randomness of a mole of substance. Thus, the larger and complex a molecule is, the larger will be its molar entropy.
The molar entropy of gases is higher than liquids which is turn is higher than solid.
Here , NO2 is a gas with higher complex structure (trigonal planar) than N2 (linerar), N2O (linear) and N2O2 (linear)
Hence, NO2(g) will have greatest standard molar entropy
Option A is correct
When a nucleus emits a positron, its atomic number is lowered by one but its mass number stays the same.
