D:
When electrons are gained, the charge of the atom decreases.
When you are given an atom with a charge, the oxidation of that atom is the charge. So by going from a Cr^3+ (Oxidation Number = 3) to a Cr^2+ (Oxidation Number = 2), the Oxidation Number thus decreases.
I can describe one prop. of energy: it can not be created or destroyed. It can be transferred, or converted, though.
Answer:
A. the ration is 2 to 3, 2Al + 3H2SO4 has the same balance as 18Al + 3H2SO4
2/3 = 18/27
B. Doesn't need an explanation other than the work you did to balance it.
Answer:
0.01 mol of H+.
Explanation:
Equation of reaction:
Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)
Molar concentration = number of moles/volume
= 1*0.01
= 0.01 mol.
Dissociation:
2HCl --> 2H+ + 2Cl-
By stoichiometry,
If 2 mole of HCl dissociates to guve 2 moles of H+
Number of moles of H+ = 0.01 mol.
