C. 5. The number of molecules in 10.0 moles of HBr is: a. 6.02x10 4.88x10 b. 6.02x10 none of the above 4.88x10 6. Chlorine has two naturally occurring isotopes, namely C1-35 and C1-37. The composition of chlorine is 25.0 % C-37 and 75.0% C1-35. The average atomic mass of chlorine is: a. 36.5 u d) 34.6 u b. 35,5 u 32.0 u C 45.5 u 7. Which statement is not true of the limiting reagent in a chemical reaction: a. it is all used up during the chemical reaction b. of all the reactants, it is always the one that has the least mass It controls how much of the product is formed d both (a) and (b) both (a) and (c) C