[填空题]
A given mass of magne- p u+3xi:bbitsibi)yij j h;fxlmj*10 *um was added to 500cm$^3$ of aqueous hydrochloric acid in a Styrofoam cup to form magnesium chloride. The temperature at the start was 18$^{\circ}C$ and after the magnesium had dissolved, the temperature rose to 20$^{\circ}C$
1.State a balanced chemical equation for this reaction. Mg+ HCl → MgCl$_2$ + $H_2$
2.Given that the change in enthalpy, ΔH is0.185kJ and the specific heat capacity of water is 4.18Jg$^{-1}$K$^{-1}$, calculate the mass of magnesium added to the hydrochloric acid. m= g.
3.Determine the systematic errors caused by the use of styrofoam cups.
