Answer:
false
Explanation:
Because in a periodic table they are not located below each other and therefore do not have the same number of electrons.
When you combine any thing together that you cant take apart is a Physical Change.
Explanation:
If 50.0 grams of Zinc are reacted with 50.0 grams of Hydrogen Chloride ... 50.09 Zn x 1 mol Zn , Imol ZnCl2 , 136.4g. ... If a decomposition reaction produces a 75.0% yield for the oxygen by mass (128.0 grams were.
Answer:
11.3 g of
are produced from 36.0 g of 
Explanation:
1. The balanced chemical equation is the following:

2. Use the molar mass of the
, the molar mass of the
and the stoichiometry of the balanced chemical reaction to find how many grams of
are produced:
Molar mass
= 18
Molar mass
= 17

Therefore 11.3 g of
are produced from 36.0 g of 
Answer:
14.77 mol.
Explanation:
- It is known that every 1.0 mole of compound or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.
<u><em>Using cross multiplication:</em></u>
1.0 mole of He contains → 6.022 x 10²³ atoms.
??? mole of He contains → 8.84 x 10²⁴ atoms.
<em>∴ The no. of moles of He contains (8.84 x 10²⁴ atoms) </em>= (1.0 mol)(8.84 x 10²⁴ atoms)/(6.022 x 10²³ atoms) =<em> 14.77 mol.</em>