A catalyst is when a chemical reaction occurs faster than normal.
The system is unaffected during a catalyst because both forward and reverse reactions are affected, meaning that quilibrium will occur faster nothing will change.
Hope it helped,
BioTeacher101
It mean it consisted of 1 g of lead and 0.077 g of O2.
divide these numbers by molar mas.
1/82=0.012 Pb /0.004 = 3
0.077/16= 0.004 O /0.004 =1
Pb3O