Combination of AH AH, and He needed (using Hess s law).
Reaction Equation
AH (kJ/mol)
Reaction | Mg(s) + 2HCl(aq)-MQCI (aq) . H.(g)
Reaction 2. MgO(S) 2HCl(aq)
MgCl(aq) . H.000
(trom row 9)
(from row 9)
-286 (published value)
Reaction 3. H:(9)
0_49) -
H. O(
Sagnes
combustionMg(s) + Vog) - MgO(s)

I'm sorry but i'm only grade

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.

is the answers your welcome! : )

Why are people no giving enough information these days