Question

select the correct collision theory explanation for changing the rate of the given chemical reaction. refrigerate food to keep it from spoiling. raise the boiling point of water with a pressure cooker. add inert water to a reaction solution. grind a metal into a fine powder. compress the air/fuel mixture inside an engine cylinder with a piston. done

Explanation:

1. Refrigerating food: Lowering temperature decreases the kinetic energy of reactant - molecules (microbes and food components), reducing collision frequency and reaction rate.
2. Raising boiling point with a pressure - cooker: Increased pressure increases the temperature at which water boils. Higher temperature increases the kinetic energy of reactant molecules, increasing collision frequency and reaction rate.
3. Adding inert water to a reaction solution: Dilution reduces the concentration of reactant molecules. Fewer reactant molecules per unit volume decrease the collision frequency and reaction rate.
4. Grinding a metal into a fine powder: Increases the surface area of the metal. More surface - exposed metal atoms are available for collisions with other reactant molecules, increasing the reaction rate.
5. Compressing the air/fuel mixture in an engine cylinder: Increases the concentration of reactant molecules (air and fuel). Higher concentration leads to a higher collision frequency and reaction rate.

Answer:

1. Decrease reaction rate by lowering temperature (decreasing collision frequency).
2. Increase reaction rate by increasing temperature (increasing collision frequency).
3. Decrease reaction rate by dilution (decreasing collision frequency).
4. Increase reaction rate by increasing surface area (increasing collision frequency).
5. Increase reaction rate by increasing concentration (increasing collision frequency).