Question

how many moles are there in each one of the following
a) 280g 9f silicon
b) 12.046×10^25 atoms of phosphorus
3)19.0 atoms of fluorine

Answer 1

( 1 )

28 g ------------------ 1 mol

1 g ---------------------1/28 mol

280 g ----------------280/28 = 10 mol.

( 2 )

1.6022×10^23 atoms ----------------1 mol

1 atom ------------- 1/1.6022×10^23 mol

12.046×10^25 atoms - 12.046×10^25/1.6022×10^23 mol

= 7.51 × 10 ^2 mol.

( c )

1.6022 × 10^23 atoms -------- 1mol

1 atom -------------- 1/1.6022×10^23 mol

19 atom ------- 19 / 1.6022×10^23 mol

= 11.85 × 10^-23 mol .

Answer 2

280 g of silicon is that so firsty you can answer what silicon atomic mass 28 u so we can 280 / 28 =10 moles