Answer:
number of valence electrons
Explanation:
The chemical properties of the atoms of elements in a group of the periodic table is most closely related to the number of valence electrons. All the chemical properties can be justified just by the number of valence electrons.
Answer
A. -1305 kJ
Explanation
Given:
Equation: C2H4(g) + 302(g) ---- > 2C02(g) + 2H20(l).
Formation ΔH values:
for C2H4(g) = 52.30 kJ/mol,
for 02(g) = 0 kJ/mol,
for CO2(g) = -393.5 kJ/mol, and
for H20(1) = -285.8kJ/mol.
What to find:
The ΔHrxn from the ΔH of formation for the given reaction.
Step-by-step solution:
ΔHrxn = (Sum of ΔH formation for the product) - (Sum of ΔH formation for the reactants).
ΔHrxn = (ΔH for 2CO2(g) + ΔH for 2H2O(l)) + (ΔH for C2H4(g) + ΔH for 3O2(g))
ΔHrxn = [(2 x -393.5) + (2 x -285.8)] + [52.30 + (3 x 0)]
ΔHrxn =(-787.0 - 571.6) + (52.30 + 0)
ΔHrxn = -1358.6 + 52.30
ΔHrxn = -1306.3 kJ
so the closest answer is A. -1305 kJ
