General Chemistry
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Determine if the following statement about the standard state of a substance is true or false, and correct if false: The standard state of a substance is the most stable solid form of a pure substance at 0°C and 1 atm pressure (for solutes, 1 M at 0°C).
Define the standard state of elements and explain why their ∆H°f is always equal to zero.
Identify the elements in their standard states required for the formation equation of C6H12O6(s) and write the balance reaction. Find the standard enthalpy of the formation using the standard table of values.
Consider the statements about standard enthalpy of formation. Identify which statements are true.
i) a measure of the energy released or consumed when one mole of a substance is created under standard conditions from its pure elements.
ii) standard enthalpy of formation is always positive
iii) the elements used in the formation equation to calculate standard enthalpy of formation are always in gas phase
Provide the formation equation of N2O4(g) from its elements in their standard state. What is the ΔH°rxn?
Write the formation equation for CH4 from the standard states of its elements and give its standard enthalpy of formation
Oxygen gas, O2, is very reactive while argon gas is inert. But why do both oxygen gas and argon gas have zero standard enthalpies of formation?
Give the equation for the formation of KClO4(s) from the standard states of its elements and determine its ΔH°f
Give the equation for the formation of SO2(g) from the standard states of its elements and determine its ΔH°f
Write the formation equation used for calculating the enthalpy of formation of Fe2O3(s).
Which of the following substances are in their standard state?
a) I2(g) at 2 atm
b) C(l)
c) Br2(g) at 25 °C
d) Fe(s)
e) CH4(g) at 1 atm and 298 K
Which reaction refers to the formation of C2H5OH?
a) C2H5OH(l) → 2 C(s) + 3 H2(g) + 1/2 O2(g)
b) 2 C(g) + 6 H(g) + O(g) → C2H5OH(l)
c) C2H5OH(l) → 2 C(l) + 6 H(l) + O(l)
d) 2 C(s) + 3 H2(g) + 1/2 O2(g) → C2H5OH(l)
Provide the balanced formation equation for Na2SiO3(s) using elements in their standard states.