Temperature Changes RPA

What does exothermic mean?

• Energy is transferred from reaction to surroundings, in the form of heat

• Energy is transferred from surroundings to reaction, in the form of heat

• Energy is transferred from reaction to surroundings, in the form of kinetic energy

• Energy is transferred from surroundings to reaction, in the form of kinetic energy

What does endothermic mean?

• Energy is transferred from reaction to surroundings, in the form of heat

• Energy is transferred from surroundings to reaction, in the form of heat

• Energy is transferred from reaction to surroundings, in the form of kinetic energy

• Energy is transferred from surroundings to reaction, in the form of kinetic energy

What is the best equipment for measuring temperature changes?

• Measuring cylinder

• pH probe

• Thermometer

• Polystyrene cup

What must you do before you add the acid and alkali together?

• Estimate the final volume of the solution

• Measure the starting temperature of the acid

• Put a lid on it

• Add water to the acid

What is the correct method for this RPA?

• Add 5cm³ increments of sodium hydroxide to the acid and measure the final temperature after all of it has been added

• Measure the acid starting temperature, add 5cm³ increments of sodium hydroxide and measure the final temperature after all of it has been added

• Add 40cm³ of sodium hydroxide and 30cm³ acid together and measure the temperature at the end

• Measure the acid starting temperature, add 5cm³ increments of sodium hydroxide and measure the maximum temperature reached after each addition

What are the total volumes used?

• 40cm³ of acid, 30cm³ of sodium hydroxide

• 300cm³ of acid, 400cm³ of sodium hydroxide

• 400cm³ of acid, 300cm³ of sodium hydroxide

• 30cm³ of acid, 40cm³ of sodium hydroxide

Why is a polystyrene cup used?

• It makes the set up more stable

• It provides some insulation so you measure a more accurate temperature change

• It allows the thermometer to stand up

• To keep the solutions as cold as possible

What is the independent variable?

• Maximum temperature reached after addition of sodium hydroxide

• Concentration of acid

• Concentration of sodium hydroxide

• Volume of sodium hydroxide added

What is the dependent variable?

• Maximum temperature reached after addition of sodium hydroxide

• Concentration of acid

• Concentration of sodium hydroxide

• Volume of sodium hydroxide added

What is some control variables? (tick two)

• Maximum temperature reached after addition of sodium hydroxide

• Concentration of acid

• Concentration of sodium hydroxide

• Volume of sodium hydroxide added