Thermochemical Equations

C+ O₂ --> CO₂ + 60kJ, what is the value for ΔH for the reaction?

• +60

• -60

• there is no way to know

Tags

NGSS.HS-PS1-4

What will ΔH be if there is 1 mole of oxygen?

• -500 kJ

• 500 kJ

• -750 kJ

• -4500 kJ

Tags

NGSS.HS-PS1-4

What is ΔH if 2 mol of O₂(g) is reacted in this reaction?

• -570 kJ

• -71.45 kJ

• -1143.2 kJ

• -142.9 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The enthalpy change for the reaction C(s, graphite) + 1⁄2O₂(g) --> CO(g) cannot be measured directly since some carbon dioxide is always formed in the reaction. It can be calculated using Hess’s Law and the enthalpy changes of combustion of graphite and of carbon monoxide. C(s, graphite) + O₂(g) --> CO₂ ΔH=-394 kJmol^–1 CO(g) + 1⁄2O₂(g) --> CO₂ ΔH=-283 kJmol^–1 The enthalpy change for the reaction of graphite with oxygen to give carbon monoxide is

• -677 kJmol^–1

• +111 kJmol^–1

• -111 kJmol^–1

• +677 kJmol^–1

Tags

NGSS.HS-PS1-4

2N₂ + 3H₂ --> 2NH₃ + 46 kJ
How much energy would be produced if only 1 mol of nitrogen was reacted?

• 92 kJ

• 0.143 kJ

• 23 kJ

• 15 kJ

Tags

NGSS.HS-PS3-1

Is the following exothermic or endothermic?

• Endothermic

• Exothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

What type of reaction is shown in the reaction pathway?

• endothermic reaction

• exothermic reaction

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Consider the following reactions:Fe(s) + 1/2 O2(g) --> FeO(s) H= -272.0 kJ2 Fe(s) + 3/2 O2(g) --> Fe2O3(s) H= -825.5 kJDetermine the delta H for the reaction: 2 FeO(s) + 1/2 O2(g) --> Fe2O3

• -281.5 kJ

• -1097.5 kJ

• -1369.5 kJ

• 281.5 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The enthalpy change for the reaction, ∆H_r , is equal to 

• ∆H₁ + ∆H₂

• ∆H₁ - ∆H₂

• -∆H₁ - ∆H₂

• -∆H₁ + ∆H₂

Tags

NGSS.HS-PS1-4

Solid magnesium dissolves in a hydrochloric acid, releasing hydrogen gas and heat from a solution of magnesium chloride. What is the sign on ΔH for this reaction?

• Negative because it is exothermic

• Negative because it is endothermic

• Positive because it is exothermic

• Positive because it is endothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4