Open Question
Write an equation for the formation of C2H4(g) from its elements in their standard states, and find ΔH°rxn for it in Appendix IIB.
8. Thermochemistry
Formation Equations
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Which of the following is the correct formation equation for SnO2(s) from its elements in their standard states?
A
2Sn(s) + O2(g) → 2SnO2(s)
B
Sn(s) + O2(g) → SnO2(s)
C
Sn(s) + 2O(g) → SnO2(s)
D
SnO(s) + O2(g) → SnO2(s)
Verified step by step guidance1
Identify the elements involved in the formation of SnO2(s). The elements are tin (Sn) and oxygen (O).
Determine the standard states of these elements. Tin (Sn) is a solid in its standard state, represented as Sn(s), and oxygen (O) is a diatomic gas in its standard state, represented as O2(g).
Write the formation equation for SnO2(s) from its elements in their standard states. The formation equation should involve one mole of the compound being formed from its elements in their standard states.
The balanced formation equation should have one mole of SnO2(s) on the right side. Therefore, the equation should be: Sn(s) + 1/2 O2(g) → SnO2(s).
Verify that the equation is balanced in terms of both mass and charge. In this case, the equation is balanced as there is one Sn atom and one O2 molecule on both sides, forming one SnO2 molecule.
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