4-7-2021

Which of the following reactions is associated with the standard enthalpy of formation of NH3 (g)?

(1/2)N2 (g) + (3/2)Which of the following reactions is associated with the standard enthalpy of formation of NH3 (g)?

Calculate the standard enthalpy change for the reaction SiO2 (s) + 4HF (g) → SiF4 (g) + 2H2O (l) given the information in the table below.

-183.6 kJ

Given the following thermochemical equations: 3A → 2B; ΔH = x kJ C → B; ΔH = y kJ What is the total enthalpy change for the reaction: 3232A → C?

1/2x - y

Calculate ΔH°rxn for the reaction A + 2B → 2C using the ΔH°f values given below.

2(c) - (a) - 2(b)

Consider the following reactions: 2A → B; ΔH = x 2B → C; ΔH = y What is the total enthalpy change for the reaction 4A → C?

2x + y

To generate the overall equation A → 2C, which two equations should be added together?

B → 2C A → B

The standard enthalpy of formation of a compound is the enthalpy change associated with the reaction that generates ___ mole(s) of that compound from its component ____ when all of the substances are under ____ conditions.

Blank 1: 1, one, or 1.0 Blank 2: elements Blank 3: standard, standard-state, or standard state

For a reaction that proceeds through a series of steps, ΔHoverall = ΔH1 + ΔH2 + ΔH3 + ....

Blank 1: Hess's, Hess', or Hess

By definition, the standard enthalpy of formation of a pure ____ in its standard state is equal to 0 kJ/mol.

Blank 1: element

The standard enthalpy of ____ is the change in enthalpy associated with the chemical reaction that generates 1 mole of a substance from its constituent ____in their standard states.

Blank 1: formation Blank 2: elements

Two equations must be manipulated in order to generate the overall equation Br2 + 2NO → 2NOBr. Select the two chemical equations from below that can be arranged and added together to generate the overall equation. (Note: the equation(s) may need to be reversed or multiplied by a constant.)

Br2 + NO → NOBr2 2NOBr → NOBr2 + NO

Which of the following reactions would have an enthalpy change equal to ΔHf°? Select all that apply.

C(graphite) + O2 (g) → CO2 (g) Fe (s) + 3/2 Cl2(g) → FeCl3 (s)

What is the net equation when the following reactions are summed? 2C(graphite) + 3H2 (g) → C2H6 (g) C2H4 (g) → 2C(graphite) + 2H2 (g)

C2H4 (g) + H2 (g) → C2H6 (g)

Which of the following substances would have a standard enthalpy of formation equal to 0 kJ/mol? Select all that apply.

H2 (g) Hg (l) Ar (g)

For a reaction that proceeds through a series of steps, ΔHoverall = ΔH1 + ΔH2 + ΔH3 + .... This is a restatement of ____ law

Heiss

fUsing Hess's law, select the manipulations to the given steps necessary to generate the overall chemical equation for the combustion of diamond to carbon monoxide (a difficult and expensive experiment). Select all that apply, including the correct overall equation. We are given the following thermochemical equations Eqn 1: C(graphite) + O2(g) → CO2(g) ΔH1 = -393.5 kJ Eqn 2: 2CO(g) + O2 (g) → 2CO2(g) ΔH2 = -566.0 kJ Eqn 3: C(diamond) → C(graphite) ΔH3 = -1.88 kJ

Overall equation is 2C(diamond) + O2(g) → 2CO(g) ΔHrxn = -224.8 kJ 2C(graphite) + 2O2(g) → 2CO2(g) ΔH1' = 2ΔH1 = -(2)393.5 kJ = -787.0 kJ 2C(diamond) → 2C(graphite) ΔH3' = 2ΔH3 = -(2)1.88 kJ = -3.76 kJ 2CO2(g) → 2CO(g) + O2(g) ΔH2' = -ΔH2 = +566.0 kJ

Using Hess's law, select the manipulation to the given formation equations necessary to generate the overall chemical equation for the combustion of diamond to carbon dioxide (an expensive experiment). Select all that apply, including the correct overall equation. We are given the following formation equations Eqn 1: C(graphite) + O2(g) → CO2(g) ΔH1 = -393.5 kJ Eqn 2: C(graphite) → C(diamond) ΔH2 = 1.88 kJ

Overall equation is C(diamond) + O2(g) → CO2(g) ΔHrxn = -395.4 kJ C(diamond) → C(graphite) ΔH2' = (-1)ΔH2 = -1.88 kJ

Generate the equation A + 2B → 2D from a combination of the reactions provided. Reaction 1: A + 2B → 2C Reaction 2: C → D How must reactions 1 and 2 be combined to sum to the overall reaction?

Reaction 1 + 2(Reaction 2)

Match the effects of the following combinations of Reactions 1 and 2 with the reaction resulting from these combinations. Reaction 1: A → 2C Reaction 2: C → B

Rxn 1 + (-Rxn 2): A + B → 3C Rxn 1 + 2(Rxn 2): A → 2B (-Rxn 1) + (-Rxn 2): B + C → A

An element that is in its most stable form at ordinary atmospheric pressure is in its ______ state (usually signified by a degree sign).

standard

Hess's law states that the enthalpy change for an overall process (which can be broken into multiple steps) will be equal to the _____ of the enthalpy changes of its individual steps.

sum

Select the answer that best completes the following sentence. The standard enthalpy of formation, ΔHfo, is ______.

the enthalpy change when one mole of a substance is formed from its constituent elements in their standard states

Consider the following reactions: A → 2B; ΔH = x kJ B → C; ΔH = y kJ What would be the enthalpy change associated with the reaction below? A → 2C

x + 2y

CO (g) can be produced by the reaction of coal with steam, as shown by the balanced equation: H2O (g) + C (s) → CO (g) + H2 (g). Which of the following options correctly reflect the steps required to calculate ΔH for this reaction, given the information shown below? Select all that apply. Reaction 1: H2 (g) + 1212O2 (g) → H2O (g); ΔH = -242.0 kJ Reaction 2: 2CO (g) → 2C (s) + O2 (g); ΔH = +221.0 kJ

ΔH = +131.5 kJ Reaction 2 must be reversed and divided by 2.

Match each thermodynamic symbol with its correct definition. Instructions

ΔHrxn: The change in enthalpy for a given reaction ΔHorxn: The enthalpy change of a reaction measured at the standard state ΔHof: The enthalpy change when 1 mol of a compound forms from its elements in their standard states