Enthalpy Lesson

Energy in exothermic reactions are

• released
• absorbed

Tags

NGSS.HS-PS1-4

Endothermic reactions feel

• warm
• cold

Tags

NGSS.HS-PS1-4

Which statement is true regarding endothermic reactions?

• a) Temperature change is positive and enthalpy change is positive
• b) Temperature change is positive and enthalpy change is negative
• c) Temperature change is negative and enthalpy change is positive
• d) Temperature change is negative and enthalpy change is negative

Tags

NGSS.HS-PS1-4

Which of the following shows the enthalpy of formation of sodium iodide

• Na_(s) + 1/2 I_2(s) --> NaI_(s)

• Na_(s) + 1/2 I_2(g) --> NaI_(s)

• Na_(s) + I_(g) --> NaI _(s)

• Na⁺_(g) + I^-_(g) --> NaI _(s)

Tags

NGSS.HS-PS1-4

10. Which label on the diagram accurately identifies the Activation energy for an endothermic reaction? a) A b) B c) C d) D

• C
• D
• E
• F

Tags

NGSS.HS-PS1-4

How do you calculate Enthalpy of a reaction?

• ΔH = ΔH_products - ΔH_reactants

• ΔT = q / mC

• ΔG = ΔH -TΔS

• E = mc²

Refer to the following question:
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-PS1-4

NGSS.HS-PS3-1

Calculate the enthalpy of reaction (ΔH).

4CO_{2 (g)} + 6H₂O _(g) → 2C₂H_{6 (g)} + 7O_{2 (g)}

ΔH_f^o [CO_2(g)] = -393.5 kJ

ΔH_f^o [H₂O_(g)] = -241.8 kJ

ΔH_f^o [C₂H_6(g)] = -84.7 kJ

• 550.647 KJ/mol

• 2855.584 KJ/mol

• -550.647 KJ/mol

• -2855.584 KJ/mol

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

When ammonium nitrate dissolves in water, the solution gets cold. Which is true?

• Reaction is ENDOTHERMIC with positive ΔH
• Reaction is ENDOTHERMIC with -ΔH
• Reaction is EXOTHERMIC with a -ΔH
• Reaction is EXOTHERMIC with +ΔH

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Specific heat capacity is

• heat energy needed to raise temp by 1C
• heat energy needed to raise temp of 1g of substance by 1C
• heat energy absorb to raise 1g of substance to higher temp
• heat energy need to raise temp for 1g of substance