Energetics

Enthalpy changes of reactions, AH

• is the heat energy released or absorbed in a chemical reaction

• is the heat energy stagnant in a chemical reaction

Tags

NGSS.HS-PS1-4

exothermic reaction

• enthalpy of the products is lower than reactants

• enthalpy of the products is higher than reactants

Tags

NGSS.HS-PS1-4

exothermic reaction

• examples: neutralisation, dilution of a concentrated acid and dissolution of NaOH in water

• examples: dissolution of NH₄Cl and NH₄NO₃

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

NGSS.HS-PS3-4

bond formation

• in product molecules where heat is released

• in reactant molecules where heat is absorbed

Tags

NGSS.HS-PS1-4

If a chemical reaction is EXOTHERMIC, the temperature would....

• Stay the same

• Increase

• Decrease

Tags

NGSS.HS-PS1-4

Which of the following statement is true about the breaking of bonds between molecules?

• To break a bond between molecules, energy must be released by the molecule

• To break a bond between molecules, no energy is needed.

• To break a bond between molecules, energy must be absorbed by the molecule.

Tags

NGSS.HS-PS1-4

If ∆H is negative, the reaction is?

• exothermic

• endothermic

Tags

NGSS.HS-PS1-4

What is the equation to show what happens to Cl ions at the anode.

• Cl^- --> Cl + e-

• 2Cl^- --> Cl₂ + 2e-

• Cl₂ + 2e- 2Cl^-

• Cl₂ + 2e- _--> 2Cl^-

Electrolysis is .....

• conduction of electricity by the ionic compound in solid state

• conduction of electricity by ionic compound in molten and aqueous state

What is the product formed at the anode during the electrolysis of concentrated copper(II) chloride?

• copper

• chlorine

• hydrogen

• oxygen