Energetics Review

When sodium carbonate powder is added to ethanoic acid, the beaker becomes cooler. Possible enthalpy diagrams are shown. Which correctly describes the reaction?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

What is the enthalpy change, in J, when 5 g of water is heated from 10°C to 18°C? Specific heat capacity of water: 4.18 kJ kg^-1 K^-1.

• A. 5 x 4.18 x 8

• B. 5 x 10^-3 x 4.18 x 8

• C. 5 x 4.18 x (273 + 8)

• D. 5 x 10^-3 x 4.18 x (273 + 8)

Tags

NGSS.HS-PS3-1

What is the enthalpy change of the reaction, in kJ? The reaction is: 2C (graphite) + O2(g) → 2CO (g).

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Which describes an exothermic reaction?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

What is the heat change, in kJ, when 100.0 g of aluminium is heated from 19.0°C to 32.0°C? Specific heat capacity of aluminium: 0.90 J g^-1 K^-1.

• A. 0.90 × 100.0 × 13.0

• B. 0.90 × 100.0 × 286

• C. 0.90 × 100.0 × 13.0 / 1000

• D. 0.90 × 100.0 × 286 / 1000

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Refer to the diagram showing the progress of a reaction on an enthalpy graph. Which is the enthalpy change of reaction, ΔH?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

The potential energy profile of a reaction is shown. What can be determined about stability and energy change from the potential energy profile shown?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

Which equation shows the enthalpy of formation, ΔH_f, of ethanol?

• 2C(s) + 3H2(g) + 1/2 O2(g) → C2H5 OH (g)

• 4C(s) + 6H2(g) + O2(g) → 2C2H5 OH (g)

• 2C(s) + 3H2(g) + 1/2 O2(g) → C2H5 OH (l)

• 4C(s) + 6H2(g) + O2(g) → 2C2H5 OH (l)

Tags

NGSS.HS-PS1-4

What is the H — H bond enthalpy, in kJ mol⁻¹, in the H₂ molecule? Consider the reaction: 2H₂(g) + O₂(g) → 2H₂O(g) where ΔHf(H₂O) = x kJ mol⁻¹. Use the bond enthalpy values for O=O and O-H bonds provided in the table.

• A.

• B.

• C.

• D.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-4

Which statement is correct?

• O₃ bond dissociation occurs at a longer wavelength of light than O₂ bond dissociation.

• O₃ bond dissociation occurs at a higher energy than O₂ bond dissociation.

• O₃ bond lengths are shorter than O₂ bond lengths.

• O₃ bond dissociation occurs at a higher frequency of light than O₂ bond dissociation.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3