Answer:
m = 998 g
Explanation:
Hello there!
In this case, according to the definition of the molar mass as the mass of one mole of the compound, it is possible to state the 1 mole of C8H18 has a mass of 114.26 grams; therefore, the mass in 8.65 moles turn out to be:

In agreement to the notation requirement.
Best regards!
Answer:
U= 238g/mol
U2O5= 556g/mol
Explanation:
Since U= 238
O=16
U3O5= 2(238)+3(16)=556g/mol