1) Assuming that you are limited to the standard glassware and equipment availab
ID: 486644 • Letter: 1
Question
1) Assuming that you are limited to the standard glassware and equipment available in the Chemistry lab room, write a procedure to determine the density of an oil.
2) In one student's experiment, they mounted an iron ring on a ring stand. Taking the tin can with two holes cut in the top and insert a glass rod, then hanging the can on the iron ring. Next, they weighed the empty tin can. Add approximately 100 mL of water to the can and re-weigh to calculate the mass of water in the can. The tin can containing 100 mL of water showed a temperature increase of 9.65°C. Determine the energy content of this fuel (in J/g) if the student began with 2.655 g of biodiesel.
3) Is the combustion of biodiesel an endothermic or exothermic process? Why?
Explanation / Answer
1) a Take the measuring cylinder and measure its mass, in grams, as accurately as possible.
b Take the measuring cylinder off the balance and add the water carefully, either by careful pouring or with a pipette until the level is as close to the 10 ml mark as possible. Put the measuring cylinder back on the balance. Measure and record the new mass (cylinder plus water), in grams.
c Repeat the procedure, adding 10 ml at a time as accurately as possible and recording the volume and total mass, until the measuring cylinder is full. Then, for each volume calculate the mass of the liquid alone.
NOTE: If a 250 ml measuring cylinder is being used you may wish to use 20 ml or 25 ml intervals.
d Repeat steps a to c for the oil (and any other liquids being tested).
e Draw a graph of mass of liquid (y-axis) against volume (x-axis). Try to scale the graph so that you can plot all your data sets on a single graph.
f For each set of data try and draw a straight ‘best fit’ line passing through the origin. Calculate the density of each liquid from the gradient of its graph line.
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