When 0.655 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 107C is observed.
Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC.
(Note: Pay attention to significant figures. Do not round until the final answer.)
The molar heat of reaction, H rxn, for the reaction of
Ca(s) + 2H+(aq) Ca2+(aq) + H2(g)
is kJ/mol.
See previous response.
When 0.655 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 107C is observed. Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC. (Note: Pay attention to significant figures. Do no
To find the molar heat of reaction (ΔH_rxn) for the given reaction, we need to calculate the heat (q) produced by the reaction when 0.655 g of Ca reacts with excess HCl.
The heat produced by the reaction can be calculated using the equation: q = m * C * ΔT
Where:
q = heat produced
m = mass of the substance (in grams)
C = heat capacity of the substance (in J/g°C)
ΔT = change in temperature (in °C)
First, let's calculate the mass of Ca:
mass of Ca = 0.655 g
Next, we need to calculate the change in temperature (ΔT) for the reaction. The given information tells us that the temperature increased by 107°C.
ΔT = 107°C
Now, we can calculate the heat produced by the reaction (q):
q = (mass of Ca) * (heat capacity) * (ΔT)
Substituting the given values:
q = (0.655 g) * (4.184 J/g°C) * (107°C)
Now, calculate the heat produced, q, using a calculator:
q = 0.655 g * 4.184 J/g°C * 107°C
The resulting value of q will give us the heat produced by the reaction.
Once we have the value of q, we can use it to find the molar heat of reaction (ΔH_rxn). The equation for molar heat of reaction is:
ΔH_rxn = q / (moles of reacting substance)
To find the moles of Ca reacting, we need to use the molar mass of Ca, which is 40.08 g/mol.
moles of Ca = mass of Ca / molar mass of Ca
Substituting the given values:
moles of Ca = 0.655 g / 40.08 g/mol
Now, using the value of q and the moles of Ca, we can calculate the molar heat of reaction (ΔH_rxn):
ΔH_rxn = q / (moles of Ca)
Substituting the calculated values:
ΔH_rxn = q / (0.655 g / 40.08 g/mol)
Finally, calculate the molar heat of reaction (ΔH_rxn) by dividing q by the mole value, using a calculator. The calculated value will give us the molar heat of reaction in kJ/mol.