Question

The data Lavoisier obtained in the experiment described on page 35 are as follows:

 

After heating: glass vessel + tin calx + remaining air                                      = 13 onces, 2 gros, 2.50 grains

                                                                                                                                                = 13 onces, 2 gros, 2.50 grains

                                 

 

How closely did Lavoisier’s results conform to the law of conservation of mass?

(1 livre = 16 onces; 1 once = 8 gros; 1 gros = 72 grains. In modern terms, 1 livre = 30.59 g.)

Answer 1

The sensitivity of Lavoisier’s balance can be as little as 0.01 grain,  which seems to be the limit of the readability of the balance; alternatively, it can be as large as 3.12 grains, which assumes that all of the error in the experiment is due to the (in)sensitivity of the balance. Convert 0.01 grains and 3.12 grains to grams. Lavoisier’s results conform closely to the law of conservation of mass. The difference between reactant mass and product mass (in grams) falls between the maximum error of a common modern laboratory balance and the minimum error of a good quality analytical balance.