Calirometry Flashcards
What are the control variables in this test? (What is kept the same to ensure a fair test?)
1) The same calorimeter so that the mass stays the same
2) Whenever you weigh the spirit burner, keep the same cap on because then it stays the same
3) The distance between the spirit burner and the bottom of the calorimeter the same
4) Use the same type of alcohol so that they burn the at the same rate
5) The volume of water in the calorimeter
What is the equation for energy transferred?
energy transferred = mc🔺t
What is the equation for efficiency?
efficiency = energy transferred
——————-
mass of fuel (g)
What are the sources of error in this experiment? (How could this experiment be improved to make the results more reliable?)
1) When we were measuring the mass of the spirit burner, we could have measured it to more than one decimal place
2) When we were measuring the initial temperature, the test tube had not fully cooled down from the last experiment, so it was still falling, so next time we could wait for longer before seeing what temperature the water was
3) When measuring 100ml of water, we could have taken more care to make sure that we did have exactly 100ml and not significantly more or less, as this would have affected our efficiency results and calculations
What is the conclusion?
1) Some fuels are much more efficient than others
2) Some fuels release more energy per gram than others.
What do you have to measure?
1) Amount of water - it takes longer to heat up more water
2) Mass of the fuel - before and after
3) Temperature of the water - before and after
What do you need to know?
Specific heat capacity of water
What does e = mc🔺h mean?
heat given out = mass of the substance that is being heated (not the fuel (g)) x the specific heat of a substance x the change in temperature
During the following reaction, the temperature of the reaction decreases.
AB + C —> AC + B
Which bond is stronger A-B or A-C?
A-B because more energy is required to break the A-B bond than is released when A-C bond is formed. That energy is taken in from the surroundings in the form of heat.
What is this experiment?
A spirit burner is heated (it has a wick in it). The alcohol heats the water in the calorimeter, until it evaporates
