PAGS

Question 1

CALORIMETER PAG STEPS

Answer 1

 washes the equipment (cup and pipettes etc) with the solutions to be used
 dry the cup after washing
 put polystyrene cup in a beaker for insulation and support
 Measure out desired volumes of solutions with volumetric pipettes and transfer to
insulated cup
 clamp thermometer into place making sure the thermometer bulb is immersed in solution  measure the initial temperatures of the solution or both solutions if 2 are used. Do this
every minute for 2-3 minutes
 At minute 3 transfer second reagent to cup. If a solid reagent is used then add the
solution to the cup first and then add the solid weighed out on a balance.
 If using a solid reagent then use ‘before and after’ weighing method
 stirs mixture (ensures that all of the solution is at the same temperature)  Record temperature every minute after addition for several minutes

Question 2

what problems can u face w calorimeter pag and how to counteract

Answer 2

• If the reaction is slow then the exact temperature rise can be difficult to obtain as cooling occurs simultaneously with the reaction
• To counteract this we take readings at regular time intervals and extrapolate the temperature curve/line back to the time the reactants were added together
• We also take the temperature of the reactants for a few minutes before they are added together to get a better average temperature.

-If the two reactants are solutions then the temperature of both solutions need to be measured before addition and an average temperature is used.

Question 3

wt r some issues can face w calorimetry pag

Answer 3

• energy transfer from surroundings (usually loss)
• approximation in specific heat capacity of solution. The method assumes all solutions have the heat capacity of water.
• neglecting the specific heat capacity of the calorimeter- we ignore any energy absorbed by the apparatus.
• reaction or dissolving may be incomplete or slow.
• Density of solution is taken to be the same as water.