His revisions proved the importance of the atomic number and acknowledged why some of the elements seemed like they were out of place, even though they were in the right place.
D. Atoms form millions of molecules. :)
First calculate the initial moles of HCl.
HCl moles i = (1.45 moles / L) * 0.5 L = 0.725 moles HCl
Then calculate how much HCl is consumed by stoichiometry:
HCl moles consumed = (12.7 g Zn / 65.38 g / mol) * (2
moles HCl / 1 mole Zn) = 0.388 moles
So HCl moles left is:
HCl moles f = 0.725 – 0.388 = 0.3365 moles
For every 1 mole HCl there is 1 mole H, therefore:
H moles final = 0.3365 moles
So final concentration of H ions is:
<span>Concentration H = 0.3365 moles / 0.5 L = 0.673 M</span>
Answer:
D) burning a candle
A demonstration that contains both physical and chemical changes will be BURNING OF A CANDLE.
<em>This is because when a candle is lighted up, on the top of it (where we see flame) the oxygen and other gases present around will be chemically changed (burned up)</em>
<em>When the wax in the top of the candle will get melted due to the heat of the fire a physical change takes places.</em>
