Chemistry: Rates of Reactions and Reversible Reactions

Flashcards covering the key concepts of reaction rates, factors affecting them, methods of measurement, and reversible reactions in chemistry.

Rate of Reaction

A measure of how fast reactants are converted into products, often measured by the change in concentration of reactants or products over time.

Collision Theory

The theory that explains how reaction rates are influenced by the frequency and energy of collisions between particles.

Factors Affecting Reaction Rate

1. Temperature: Increased temperature gives particles more energy, increasing reaction rate. 2. Concentration/Pressure: Higher concentration puts more particles in a given volume, facilitating collisions. 3. Surface Area: Greater surface area allows more particles to collide. 4. Catalysts: Substances that lower activation energy to increase reaction rate without being consumed.

Catalyst

A substance that speeds up a chemical reaction by providing an alternative pathway with a lower activation energy.

Measuring Rate of Reaction

Ways to measure reaction rate include observing color change, measuring change in mass (often of gases), and calculating the volume of gas produced using a gas syringe.

Le Chatelier's Principle

States that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change.

Reversible Reactions

Reactions that can proceed in both forward and reverse directions, reaching an equilibrium point where the rates of the forward and backward reactions are equal.

Endothermic Reaction

A type of reaction that absorbs heat from the surroundings.

Exothermic Reaction

A type of reaction that releases heat to the surroundings.

Equilibrium

A state in a chemical reaction where the concentrations of products and reactants remain constant over time.

Rate of reaction calc

Amount of reactant used OR amount of product formed / time

Sodium thiosulfate & HCl practical

1) measure 10 cm cubes of sodium thiosulfate

2) place flask on piece of paper with cross

3) measure 10 cm cubed of 0.1 mol/dm cubed using measuring cylinder

4) add to conical flask

5) start timer and record how long it takes for cross to no longer be visible

6) repeat with different concentrations of HCL

Magnesium and HCL practical

1) set volume of HCl in conical flask

2) add magnesium

3) plug in gas syringe

4) start 30 sec timer and record how much gas has been collected