Answer:
D or A
<em>But I do know...</em>
It's because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.
3 minutes are left (16-13=3)
What do you mean is that a school question
Answer:
(a) Potassium 3; phosphorus 1; oxygen 4
(b) Aluminium 3; oxygen 9; hydrogen 9
(c) Iron 10; sulfur 15; oxygen 60
Explanation:
(a) K₃PO₄
In one formula unit of K₃PO₄ , there are three atoms of potassium (K), one atom of phosphorus (P), and four atoms of oxygen (O).
In two formula units there are
Potassium — six atoms
Phosphorus — two atoms
Oxygen — eight atoms
(b) Al(OH)₃
In one formula unit of Al(OH)₃, there is one atom of aluminium (Al), three atoms of O, and three atoms of Hydrogen (H).
In three formula units there are
Aluminium — three atoms
Oxygen — nine atoms
Hydrogen — nine atoms
(c) Fe₂(SO₄)₃
In one formula unit of Fe₂(SO₄)₃, there are two atoms of iron (Fe), three atoms of sulfur (S), and 12 atoms of O.
In five formula units there are
Iron — 10 atoms
Sulfur — 15 atoms
Oxygen — 60 atoms
Calcium has the least attraction for electrons in a chemical bond
