Question

how do i find the average atomic mass in a unknown metal calorimetry experiment

13 Table II. Data and Calculations for Unknown Metal, Code Number of Metal: Trial 3 Trial 1 Trial 2 Include units for all measurements Mass of metal 271.10(3) 271.119 9.000 99-200 93.20 Temp of boiling water (Tn) (initial T of metal) Mass of calorimeter 7.509 7.53 7.509 102.24 Mass of calorimeter & water Initial Temp (Tew) of calorimeter water Final temp of metal & water (inside calorimeter) Mass of water inside calorimeter Co-92 39.20 lo 00 ne.00 40.40 39.10 97.59 94.74 91.60 AT of water (Tr- Tiwi) 14.9 58 3 to.18 10-1 AT of metal (Tr- Tim)) 59.9 4124 2.5403 5५-০० Heat gained by the water Q mx c X AT *Specific Heat of metal (Cm) y035 4.147 m mm X C x AT q lost by water-q gained by metal 2.76 Average specific heat capacity of unknown metal 3.11J Average Atomic mass Calculate the range from the high & low values allowed by the uncertainty in the Law of Dulong : Petit. Possible identity of unknown element based on comparison with a table of actual c values. Some tables are given in calories/g °C, other l

Answer 1

Average atomic of unknown metal can be estimated from the Specific heat capacity of unknown metal by using the Law of Dulong and Petit.

The Law of Dulong and Petit states that the atomic mass of a solid element (metal) is equal to 25 divided by the Specific heat capacity of the element.

Atomic mass=25/Specific heat capacity

Where, specific heat capacity is in J/mol.K

According to this law, specific heat capacity of one mole of most of the solid elements is about 3R.(R=Universal gas constant).

3R value is about 25 J/mol.K

Average Atomic Mass calculated from the law of Dulong and Petit range may have + or - 10% uncertainty.