The answer is B to prevent condensation from forming on the agar surface
Answer:
ΔHrxn = -635.14kJ/mol
Explanation:
We can make algebraic operations of reactions until obtain the desire reaction and, ΔH of the reaction must be operated in the same way to obtain the ΔH of the desire reaction (Hess's law). Using the reactions:
(1)Ca(s) + 2 H+(aq) → Ca2+(aq) + H2(g) ΔH = 1925.9 kJ/mol
(2) 2H2(g) + O2 g) → 2 H2O(l) ΔH = −571.68 kJ/mole
(3) CaO(s) + 2 H+(aq) → Ca2+(aq) + H2O(l) ΔH = 2275.2 kJ/mole
Reaction (1) - (3) produce:
Ca(s) + H2O(l) → H2(g) + CaO(s)
ΔH = 1925.9kJ/mol - 2275.2kJ/mol = -349.3kJ/mol
Now this reaction + 1/2(2):
Ca(s) + ½ O2(g) → CaO(s)
ΔH = -349.3kJ/mol + 1/2 (-571.68kJ/mol)
<h3>ΔHrxn = -635.14kJ/mol</h3>
The concentration of each of the individual ions in a 0750 M Ba(OH)2 solution is
[Ba2+] = 0.750 M
[OH-]= 1.50 M
<h3>
calculation</h3>
write the equation for dissociation
that is Ba(OH)2 (s)→ Ba2+(aq) + 2OH-(aq)
by use of mole ratio of Ba(OH)2 : Ba2+ which is 1: 1 the concentration of Ba2+ is therefore= 0.750M
by use of mole ratio of Ba(OH)2 : OH- which is 1:2 the concentration of OH- =0.750 M x2/1=1.50 M
1) KCl
Potassium Chloride is an ionic bond because it exists between a metal and a nonmetal. The Potassium ion is a cation, carrying a +1 charge; the Chlorine is an anion, carrying a -1 charge.
Answer:
The 2 zeros after the decimal point
