Element. Everything is else is a mixture, therefore not pure.
Strong Acid has a lower pH level than a weak acid, weak acid pH level will be closer to 7 than the strong acid. Weak acid does not dissociate completely, therefore a weaker proton donor, thus higher pKa. Strong acids dissociates completely and release all of their hydrogen atom when dissolve in water.
Explanation:
this is the one i found.....
evaporation systems allow for an endless source of water. you can grab cups of water straight from the sea or even a lake. the use of evaporation allows for you to drink water thats even healthier than getting it from a cloud and it will leave all of the bad parts that used to be in the water in the first container you pour into. this system is most useful in hot climates such as places near the equator.
in these options not any Element are liquid at 1000k i think you type wrong in first option It is Hg not Ag and Hg is liquid at 1000 k