Question

Dax has been learning about chemical reactions, and he now understands that chemical reactions occur at different rates. Some are very fast, while others are quite slow. Depending on the conditions, a particular reaction can happen at different rates. Describe the conditions that affect the rate of a chemical reaction

Answer 1

Answer:

• concentration
• temperature
• surface area (for solid reactants ONLY)
• pressure (for gaseous reactants ONLY)
• catalyst

Explanation:

• Concentration- rate of the reaction increases with the increase of concentration of the reactants. More particles per unit volume leads to the frequency of collisions to increase. The number of successful collisions thereby increase and overall, lesser time is needed to complete the reaction (upon a higher concentration)
• Temperature- With the increase of temperature, rate of reaction increases. Particles have more kinetic energy and they move faster. Due to this, number of successful collisions increases/number of effective collisions increases. More particles have energy greater than the activation energy and, activation energy can't change. If number of moles are changed, then number of product will vary.
• Surface Area- Rate of reaction increases with the increase of surface area of the solid reactant. More particles are exposed to react and the frequency of collisions increases. Less time is needed to complete the reaction and with the decrease of size, surface area increases.
• Pressure- Rate of reaction increases with the increase of pressure of the gaseous reactants. Gas molecules are closer/ more particles per unit volume is found. The frequency of collisions increase and number of effective collisions increases.
• Catalyst- Substances which can speed up a chemical reaction by lowering the activation energy by creating an alternative route are called catalysts. They take part in a chemical reaction but after the reaction, they remains chemically unchanged. Catalysts can change the value of enthalpy change and increases both forward and backward reaction rates. They can't change the yield of a chemical reaction and can't change the equilibrium composition. (ex: usage of Vanadium (V) Oxide to manufacture sulfuric acid).