Question

I rounded the answer but can you help me?

Answer 1

I’m assuming you want your work to be checked? So I’ll just run thru my process in equations below.
3(Cu)+8(O)+2(P)

3(63.546)+8(15.999)+2(30.974) = 380.578g/mol

And then we use sig figs which makes us round to 5 sig figs and gives us 380.58 g/mol