Answer:

Explanation:
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In this case, is possible to infer that the thermal equilibrium is governed by the following relationship:

Thus, both iron's and water's heat capacities are: 0.444 and 4.18 J/g°C respectively, so one solves for the mass of water as shown below:

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Answer:
m = 65.637 g
Explanation:
Heat = 0.612 kJ = 612 J ( Converting to J by multiplying by 1000)
Initial Temperature = 30.°C
Final Temperature = 51°C
Temperature change = Final Temperature - Initial Temperature = 51 - 30 = 21°C
Mass = ?
The relationship between these quantities is given by the equation;
H = mCΔT
where c = 0.444 J/g°C
Inserting the values in the equation;
612 = m * 0.444 * 21
m = 612 / (0.444 * 21)
m = 65.637 g
8.5L H2O (1 mol H2O/22.4L)=.37946 mol H2O
.3796 mol H2O(1 mol CH4/2 mol H2O)=.18973 mol CH4
.18973 mol CH4(22.4L/1mol CH4)=4.25L CH4 gas