Thermochemistry

How much heat is required to vapourize 15.8 g CH3OH(l) at its boiling point? (∆Hvap = 38.0 kJ/mol)

• 2.41 kJ

• 18.8 kJ

• 77.0 kJ

• 600. kJ

Calculate the ∆H for the following reaction using the bond energies given below: H-H (g) + I-I (g) → 2H-I (g) Bond energies: H-H = 436 kJ/mol, I-I = 151 kJ/mol, H-I = 297 kJ/mol

• +290 kJ

• -290 kJ

• +7 kJ

• -7 kJ

Tags

NGSS.HS-PS1-4

What quantity of heat is evolved with 5.550 mol H2O(l) is formed from the combustion of H2(g) and O2(g)?

• 51.44 kJ

• 285.8 kJ

• 1586 kJ

• 2297 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Using the data below, what is the order of changes that occur when ethanol is heated from -25.0ºC to 85.0ºC?

• Phase change, temperature change

• Phase change, temperature change, phase change

• Temperature change, phase change

• Temperature change, phase change, temperature change

Tags

NGSS.MS-PS1-4

The following decomposition reaction may occur in an air bag: 2NaN₃(s) → 3N₂ (g) + 2Na(s) ∆H = -43.5 kJ What is the heat of formation, ∆Hₓ, for NaN₃?

• -43.5 kJ

• -21.8 kJ

• 21.8 kJ

• 43.5 kJ

Tags

NGSS.HS-PS1-4

A substance increases in temperature by 255ºC when a 983 g sample of it absorbs 83 200 J of heat. What is the specific heat capacity of the substance?

• 0.332 J/gºC

• 0.450 J/gºC

• 21.6 J/gºC

• 321 J/gºC

Tags

NGSS.HS-PS3-1

The activation energy of this is ___ kJ

• 160

• -80

• 80

• 240

• 40

Tags

NGSS.HS-PS1-4

If you were holding in your hand a test tube in which the reaction above is taking place, it would

• feel cold, because energy is being released

• feel cold, because energy is being absorbed

• feel hot, because energy is being absorbed

• feel hot, because energy is being released

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

The heat of reaction (ΔH, or ΔE) of this reaction is ___ kJ

• 240

• 80

• -160

• 160

• -80

Tags

NGSS.HS-PS1-4

The line that represents the heat of reaction (ΔH, or ΔE) of this reaction is

• Line A

• Line B

• Line C

• Line D

Tags

NGSS.HS-PS1-4