Answer:
7.5 gm left
Explanation:
Bismuth-210 has a half life of 5 days
15 days is 15/5 = 3 half lives
since half the amount is left in 5 days or 1 half life
(1/2) x (1/2) x (1/2) the staring amount would be left in
3 half lives. so 1/8 is left
(1/8) x 60.0 = 7.5 gm left
Qwesdfgudfdfdess de afefdfsfwrqdetgr
<span>A substance is composed entirely of one type of atom, it is known as a Chemical element
because mixture contain more than one type of atom and it cannot be neutron or isotope
so correct option is B
hope it helps</span>
Answer:
"2.48 mole" of H₂ are formed. A further explanation is provided below.
Explanation:
The given values are:
Mole of Al,
= 3.22 mole
Mole of HBr,
= 4.96 mole
Now,
(a)
The number of mole of H₂ are:
⇒ 
or,
⇒ 
⇒ 
⇒ 
(b)
The limiting reactant is:
= 
(c)
The excess reactant is:
= 
Basically since there’s 2 hydrogen’s there will be two H’s on either side of your other element. And Se is in group 6 which means it has 6 valence electrons. When you combine 6 and 2 from the hydrogen you get 8. You then should place 8 dots around Se two on each side.
So something like H Se(with 8 dogs around it) H
