Calculating Enthalpy

The SI unit of heat and energy is the __________.

• calorie
• heat
• joule
• watt

ΔH value in an endothermic reaction is a positive number.

• True
• False

4 PCl₅ + 3438 kJ --> P₄ + 10 Cl₂
How much energy is required to produce each mole of chlorine?

• 687.6 kJ
• 859.5 kJ
• 343.8 kJ
• 245.8 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

H₂ + Cl₂ --> 2 HCl + 1845 kJ
Is this reaction endothermic or exothermic?

• Endothermic 
• Exothermic

Tags

NGSS.HS-PS1-4

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

What mass of P₄ must be reacted to produce 5905 kJ of energy?
P₄ + 6Cl₂ --> 4PCl₃ + 2439 kJ

• 25.43 g
• 563.0 g
• 2.421 g
• 300.0 g

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Calculate ΔH when 6.44 g of sulfur reacts with excess oxygen, according to the following equation?
2S + 3O₂ → 2SO₃ 
ΔH = -791.4 kJ

• -79.5 kJ
• -795.0 kJ
• -41.1 kJ
• -411 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Calculate ΔH when 4.72 g of carbon reacts with excess oxygen, according to the following equation?
C + O₂ → CO₂ 
ΔH = -393.5 kJ

• -154.8 kJ
• -95.0 kJ
• -66.7 kJ
• -199.5 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

How much energy must be used to produce 4.75 mol of gaseous water?
H₂O (l) +  44.0 kJ --> H₂O (g)

• 209 kJ
• 9.36 kJ
• 209.0 kJ
• 9.362 kJ

During an endothermic reaction in a beaker if we are part of the surroundings and touched the beaker, it would feel _______.

• Warm

• Cold

• Bubbly

• Damp

Tags

NGSS.HS-PS1-4