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Reaction Energy and Rates

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is dynamic equilibrium, and how does a system respond to a stress?

Chemical equilibrium and Le Chatelier's principle: describe dynamic equilibrium in a reversible reaction and predict the shift when concentration, temperature or pressure changes.
A focused Virginia SOL Chemistry answer on equilibrium under CH.6: reversible reactions and dynamic equilibrium, and using Le Chatelier's principle to predict how an equilibrium shifts when concentration, temperature or pressure changes.
10 min answer →

How do you tell whether a reaction absorbs or releases energy?

Endothermic and exothermic reactions: distinguish endothermic and exothermic processes by the direction of energy flow and the sign of the enthalpy change.
A focused Virginia SOL Chemistry answer on reaction energy under CH.6: the difference between endothermic and exothermic reactions, the direction of energy flow, the sign of the enthalpy change, and how temperature change signals each type.
9 min answer →

What can a chemist change to make a reaction go faster or slower?

Factors affecting reaction rate: describe how concentration, temperature, surface area, a catalyst and the nature of the reactants change the rate of a reaction.
A focused Virginia SOL Chemistry answer on rate factors under CH.6: how concentration, temperature, surface area, catalysts and the nature of the reactants change reaction rate, each explained with collision theory.
9 min answer →

What does a potential energy diagram show, and what is activation energy?

Potential energy diagrams and activation energy: interpret a potential energy diagram, identify the activation energy and the energy change, and explain the effect of a catalyst.
A focused Virginia SOL Chemistry answer on energy diagrams under CH.6: reading a potential energy diagram, identifying the activation energy, the energy of the products versus reactants, and how a catalyst lowers the activation energy.
9 min answer →

Why do reactions happen at all, and what does collision theory require?

Reaction rates and collision theory: explain reaction rate using collision theory, including effective collisions, orientation and the activation energy.
A focused Virginia SOL Chemistry answer on collision theory under CH.6: what reaction rate measures, why particles must collide with enough energy and the correct orientation, the role of activation energy, and the meaning of an effective collision.
9 min answer →