The First Two Are Correct Since They Give Off Light
Answer: number of atoms is 5.21 · 10^24
Explanation: Atomic mass of Be is 9.012 g/mol.
Number of moles n = m/M = 78.0 g / 9.012 g/mol =
Multiply this with Avogadro number Na = 6.022*10^23 1/mol
Ummmmmmmmmmmmmmmmmmmmmmmmm, 21
Answer: 20
Explanation: I’m in your class.
Answer:
x=7
Explanation:
3x-3=18
-3 moves over the 18 side and becomes +3.
18 + 3 =21
3x=21
now you need to divide 3 with 21 giving you 7