Enthalpy

ΔH value in an endothermic reaction is a positive number.

• True
• False

Tags

NGSS.HS-PS1-4

What type of reaction is shown in the reaction pathway?

• endothermic reaction
• exothermic reaction

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

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

Define 'Enthalpy'

• a) Energy stored in the movement of molecules in a substance
• b) The opposite of temperature
• c) The temperature of a molecule
• d) Energy stored in the chemical bonds in a substance

Tags

NGSS.HS-PS1-4

Which statement is FALSE for an exothermic reaction?

• Reactants higher in energy and less stable
• Product lower in energy and more stable
• Products have stronger bonds than reactants
• Reactants have stronger bonds than products

Tags

NGSS.HS-PS1-4

• endothermic reaction

• exothermic reaction

• reaction with catalyst

• equilibrium reaction

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

NH₄NO₃ --> NH₄⁺ +NO₃^-

ΔH = + 27 kJ

• endothermic reaction

• exothermic reaction

• reaction with catalyst

• equilibrium reaction

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

ΔH_rxn =

• H_products - H_reactants

• H_reactants - H_products

• H_products + H_reactants

• H_reactants / H_products

Tags

NGSS.HS-PS1-4

Which one is the endothermic reaction? (Hint: look at ΔH. For endothermic reactions, should it be positive or negative?)

• 2NO₂ --> N₂O₄

  ΔH = -57.6 kJ

• N₂ + O₂ --> 2NO

  ΔH = +181 kJ