The correct answer among the choices given above is the last option. When an acid reacts with an active metal, hydrogen gas is produced. The hydrogen in acid is displaced by the metal yielding hydrogen gas.
Mg + 2HCl = MgCl2 + H2
B, a physical change because it is not destroying the substance.
Answer:
kJ/mol
Explanation:
Given and known facts
Mass of Benzene
grams
Mass of water
grams
Standard heat capacity of water
J/g∙°C
Change in temperature ΔT
°C
Heat

Heat released by benzine is - 7.82 kJ
Now, we know that
grams of benzene release
kJ heat
So,
g benzine releases

kJ/g
mol C6H6
Heat released

kJ/mol