Bond energy

Is this equation endo- or exo-thermic?

PCl₃ (s) + Cl₂ (g) --> PCl₅ (s) + energy

• endothermic

• exothermic

Tags

NGSS.HS-PS1-4

When new chemical bonds form, energy ____________.

• is taken into the system from the surroundings.

• is released from the system to the surroundings.

• stays the same in the system.

Tags

NGSS.HS-PS1-4

Which of the following represents an exothermic reaction?

• 
• 

Tags

NGSS.HS-PS1-4

Based upon the graph above, what type of reaction is this?

• Endothermic

• Exothermic

Tags

NGSS.HS-PS1-4

Use bond energies to determine the energy change for the following reaction and use the information to determine if it is an endothermic or exothermic reaction:

HCN + H₂ --> CH₃N₂

Tags

NGSS.HS-PS1-4

The average bond enthalpies for O-O and O=O are 146 and 496 kJ/mol respectively. What is the enthalpy change, in kJ, for the reaction below?

H-O-O-H(g) → H-O-H(g) + ½O=O(g)

• -102

• +102

• +350

• +394

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The following equation shows the formation of magnesium oxide from magnesium metal. Which statement is correct for this reaction?

2Mg(s) + O₂(g) → 2MgO(s) ΔH = -1204 kJ

• 1204 kJ of energy are released for every mole of magnesium reacted

• 602 kJ of energy are absorbed for every mole of magnesium oxide formed

• 602 kJ of energy are released for every mole of oxygen reacted

• 1204 kJ of energy are released for every two moles of magnesium oxide formed

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 is an example of an endothermic physical reaction? 

• a) Ice melting 
• b) Combustion 
• c) Steam condensing 
• d) Photosynthesis

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Use the chart to calculate the  $\Delta E$  for the reaction below (include unit):

 $C_2H_4\ +\ F_2\ \rightarrow\ C_2H_4F_2$  

Tags

NGSS.HS-PS1-4