Q5. the table below shows the melting points and boiling points of four elements
melting point (°c) boiling point (°c)
357
-39
element
mercury
copper
nitrogen
calcium
1085
2562
-210
-196
842
1484
answer the following using the table above. which element in the table is:
(i) a liquid at 0°c?
(ii) a solid at 1000°c?
(iii) a gas at 500°c?
(iv) what state is nitrogen at -200°c?

i. Mercury

ii. copper

iii. Mercury

iv.Nitrogen becomes a liquid at -200°C. Liquid nitrogen looks like water

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.