Question

would be liquid at 525 K (assume samples are protected from air): (a) bismuth, Bi; (b) platinum, Pt; (c) selenium, Se; (d) calcium, Ca; (e) copper, Cu.

Answer 1

Answer:

a)

Explanation:

The temperature of 525 K, so to identify which is the state of a substance, we need to now the melting and the boiling point of it, which can be found in thermodynamic tables. To be liquid, the melting point must be less than 525 K (so the substance is not a solid anymore), and the boiling point must be higher than 525 K (so the substance doesn't go to gas).

Substance      Melting point at 1 atm (K)    Boiling point  at 1 atm(K)    

Bi                          544.7                                       1837                    

Pt                          2041.4                                    4098                    

Se                           494                                        958                    

Ca                           1115                                        1757                  

Cu                          1357.77                                 2835

Thus, when pressure increase, the melting point decrease, so, if the pressure is little higher than 1 atm, then bismuth can be found as a liquid at 525 K. The others would need a higher pressure to be liquid at 525 K.