Question

△H=mC_h2o(T_i-T_f)

this is my result from lab experiment, how to get the heat change.. please explain this.

Mg ribbon	Vacid	M mg	Ti	Tf
	100 mL	.11g	22.5 C	27.8 C

MgO	Vacid	M mgO	Ti	Tf
	100 mL	.8 g	22.4 C	26.7 C

Answer 1

Solution:

C value of water is 4.186 J/gm C, T_i = 22.5 C, T_f = 27.8 C { as MgO oxidizes to give Mg the values of Mg is taken for calculating the heat change in forward direction}

Mass is calculated as Mg reduced from MgO so m = (0.11-0.8) g = 0.3 g

by substituting all the values in the equation we get,

q = (0.3) (4.186) (27.8 - 22.5)

q = 66.5574 J