A = number of mass = 31 => number of protons + number of neutrons = 31
Phosphours, Z = atomic number = 15 = number of protons
Symbol of the element phosphorus = P
=> The symbol of the isotope is the symbol of the element, P, with the number of mass, 31, to the left, as a superscript, and the atomic number, 15, to the left, as a suscript.
NaOH
Na=23
O=16
H=1
SO,NaOH=23+16+1
NaOH=40g/mol
42% of 40=42/100x40
oxygen is the compound
density=mass/volume
1.30=mass/6
mass=7.8g
3 cubic centimeters, Volume= density/ mass
I think the correct answer is c if not it’s d
Answer:
Explanation:
In Polystrene, the molecular formula for the repeat unit =
;
and the atomic weights of Carbon C = 12.01 g/mol
For Hydrogen, it is 1.01 g/mol
Hence, the repeat unit molecular weight is:
m = 8 (12.01 g/mol)+8(1.01 g/mol)
m = 96.08 g/mol + 8.08 g/mol
m = 104.16 g/mol
The degree of polymerization = no-average molecular weight/repeat unit molecular weight.
Mathematically;



