Answer:
21
Explanation:
Formula;
Mass number = number of protons + number of neutrons
= 9 + 12
= 21
Answer:
The atomic mass of phosphorus is 29.864 amu.
Explanation:
Given data:
Atomic mass of phosphorus = ?
Percent abundance of P-29 = 35.5%
percent abundance of P-30 = 42.6%
Percent abundance of P-31 = 21.9%
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass / 100
Average atomic mass = (29×35.5)+(30×42.6) + (31×21.9) /100
Average atomic mass = 1029.5 + 1278 + 678.9/ 100
Average atomic mass = 2986.4 / 100
Average atomic mass = 29.864 amu.
The atomic mass of phosphorus is 29.864 amu.
PV = nRT
1.026atm * 42l = n * 0.0821L atm/mol K * 305K
n=1.72.
1.72 molecules.
The enthalpy of formation has a negative sign, which means that the reaction is exothermic. In other words, when ethanol is formed, heat is released to the surroundings as a by-product. The reaction for the formation of ethanol is written below:
<em>C₂H₄ + H₂O → C₂H₅OH</em>
