Which element is a liquid at 758 k and standard pressure? (1) gold (3) platinum (2) silver (4) thallium
The answer would be Thalio. It is an element with Tl as its chemical symbol and atomic number 81. This post-transition mild gray steel is not freely sourced in nature. When inaccessible, thallium looks like pewter, but tarnishes when left unprotected from air.
option (4) thallium. Explanation: 1) You must respect the normal bolting and fusion points of the elements. 2) To be liquid, the normal melting point must be less than 758 K and the normal boiling point must be greater than 758 K. 3) See the data in a property manual or on the Internet, and construct a table. 4) The given temperature, 758 K, is 758 – 273.15 = 484.85 °C. Normal melting element Normal boiling state at 484.85°C point (°C) point (°C) (1) gold 1064 2700 solid (2) silver 961.8 2162 solid (3) platinum 1768 3825 solid (4 ) thallium 303.5 1457.8 liquid So the only element of choice with a melting point below 758 K (484.85) and a boiling point above that at 1 atm is thallium. So it’s liquid.
The answer is thallium good luck