Part A - Measuring H Using a Coffee-Cup Calorimeter When 0.243 g of Mg metal is
ID: 900544 • Letter: P
Question
Part A - Measuring H Using a Coffee-Cup Calorimeter
When 0.243 g of Mg metal is combined with enough HCl to make 100 mL of solution in a constant-pressure calorimeter, the following reaction occurs:
Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g)
If the temperature of the solution increases from 23.0 C to 34.1 C as a result of this reaction, calculate H in kJ/mol of Mg. Assume that the solution has a specific heat of 4.18 J/gC.
When 0.243 of metal is combined with enough to make 100 of solution in a constant-pressure calorimeter, the following reaction occurs:
If the temperature of the solution increases from 23.0 to 34.1 as a result of this reaction, calculate in of . Assume that the solution has a specific heat of 4.18 . Select one
19.1 kJ/mol 111 kJ/mol 191 kJ/mol 464 kJ/molExplanation / Answer
Supposing the solution's density to be the same as that of water:
q = m Cp dT
q= (4.18 J/gC) x (100 g) x (34.1 - 23.0)C
= 4639.8 J
moles of Mg = 0.243 / 24.30506 = 0.0099979
for 0.0099979 Mg heat
(4.6398 kJ) / (0.0099979 mol) = 464 kJ/mol
Since the reaction is exothermic, the H is negative by convention,
H = - 464 kJ/mol
answer last one