Mass = mole x molar mass
Explanation:
The mole of the substance used in the bakanced eqn multipled by its molar mass equals to Its mass
There are 30 protons and 39 neutrons in the nucleus.
This must me the isotope of an element with an atomic mass close to 69 u.
The only candidates are Zn and Ga.
Zn has a zinc-69 isotope with mass 68.926 u.
Ga has a gallium -69 isotope with mass 68.925 u.
The isotope is probably

.
It has 30 protons and 39 neutrons.
Answer:
8.17 × 10^-7
Explanation:
You would divide 3 + 10^8 with 3.67 ×10^14, Which gives you the number 8.174369 = 8.17 :)
There will be a shift towards the reactants
Add all weighs together
calculate carbons weigh
(carb weigh/total)×100