Which of the following is an element? A.
magnesium chloride salt (MgCl)
B.
hydrochloric acid (HCl)
C.
carbon monoxide gas (CO)
D.
zinc metal (Zn)

Aballoon inflated with three breaths of air has a volume of 1.7 l. at the same temperature and pressure, what is the volume of the balloon if five more same-sized breaths are added to the balloon?

What is a metal replacement reaction

The melting point of sulfur is 115 °c and its boiling point is 445 °c. what state would sulfur be in at 200 °c?