Elliot has some stearic acid. It is in the solid state. a Describe how Elliot could use the apparatus below to measure the melting point of his stearic acid. (2 marks) End-of-chapter test Chapter 2 Foundation © Oxford University Press 2015 www. oxfordsecondary. co. uk/acknowledgements This resource sheet may have been changed from the original. b Elliot writes a results table for his experiment. Complete the table by writing in the missing column heading. Include units. Time (min) () (1 mark) c Elliot does his experiment and writes his results in the table. He uses his results to draw a graph. i Write down the melting point of stearic acid. oC (1 mark) ii Draw a line on the graph to show how its shape would be different if the stearic acid was not pure.

Butadiene undergoes a reaction at a certain temperature in the gas phase as follows: 2c4h6(g) --> c8h12(g) the following data were collected for this reaction: time (min) [c4h6] (m) 0 0.36 15 0.30 30 0.25 48 0.19 75 0. determine the order of the reaction and the rate constant. 1st order and k = 4.3x10 -4 s-1 1st order and k = 2.3x10-4 s-1 2nd order and k = 4.3x10-4 s-1 2nd order and k = 2.3x10-4 s-1 zero and k = 4.3x10-4 s-1

Since the gas in your graduated cylinder is a mixture of butane and water vapor, you must determine the partial pressure of the butane, pbutane, alone. to do this, consult a reference and record the partial pressure of the water vapor, pwater, at the temperature you recorded. use the following formula to compute the partial pressure of the butane. pbutane = atmosphere - pwater use the following combined gas law formula and compute the volume that the butane sample will occupy at stp. (hint: convert both temperatures to kelvin.) pbutane x voriginal = pstandard x vfinal troom tstandard use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. grams of butane you used “x” grams of butane ml of butane corrected to stp = 22,400 ml compute the theoretical molar mass of butane based on its formula and the atomic masses on the periodic table. compare your experimental results from #3 to the theoretical value of #4, computing a percent error of your findings using this formula: % error = measured value - accepted value x 100 accepted value use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. need asap

Measurements that have similar values are: a. usually accurate b. sometimes accurate c. always accurate d. never accurate