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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: ShevzBrx on December 11, 2020, 12:38:19 AM

Title: Help on a Eutetic Phase Diagram Ag-Cu Question
Post by: ShevzBrx on December 11, 2020, 12:38:19 AM

An alloy containing 20x10 ^ 21 atoms of Ag and 73x10 ^ 21 Cu atoms is heated to 780 ° C. Determine (Consider that for Cu and Ag, the specific mass is 8.96 g / cm³ and 10.49 g / cm³ and the atomic weight 63.546 g / mol and 107.8682 g / mol, respectively.)


a) The phase (s) present.
b) The weight percentage of each phase.

Please, help   ???  : )

Title: Re: Help on a Eutetic Phase Diagram Ag-Cu Question
Post by: Borek on December 11, 2020, 03:15:46 AM

You have to show your attempts at solving the problem to receive help, this is a forum policy.

Hint: find molar ratio first.

Title: Re: Help on a Eutetic Phase Diagram Ag-Cu Question
Post by: ShevzBrx on December 11, 2020, 03:25:00 AM

i didnt know about this policy, sorry.

i'm brazilian. translating: a - present phases: alpha and liquid

i'm correct?

Title: Re: Help on a Eutetic Phase Diagram Ag-Cu Question
Post by: AWK on December 11, 2020, 04:10:14 AM

You calculated the percentage by weight correctly.
But your problem is presented ambiguously.
The melting point of an alloy with this composition is over 950°C. The 780°C temperature is only 1 degree above the eutectic temperature, so the time needed to reach equilibrium will be extremely long.
You could find the real composition of the alloy by melting it and slowly cooling it down to 780°C.