When 0.667 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 108C 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)
And the question is?? Also, add the reaction arrow.
the question is to find the molar heat of reaction of
Ca(s) + 2H+(aq)= Ca2+(aq) + H2(g) (i don't know how to do the arrow so im just gonna use the = sign)
To find the molar heat of reaction (ΔH_rxn) for the given reaction, we need to calculate the heat released in the reaction using the mass of calcium (Ca), the temperature change (∆T), and the heat capacity of the solution.
First, we need to calculate the heat released in the reaction using the formula:
q = m * C * ∆T
Where:
q = heat released or absorbed
m = mass of the substance
C = heat capacity of the substance
∆T = change in temperature
Given:
Mass of Ca = 0.667 g
Temperature change = 108 °C
Heat capacity of the solution = 4.184 J/g°C
Next, we need to convert the mass of Ca into moles using the molar mass of Ca.
The molar mass of Ca is approximately 40.08 g/mol (from the periodic table).
To convert the mass of Ca to moles, we use the formula:
moles = mass / molar mass
moles = 0.667 g / 40.08 g/mol
moles ≈ 0.01663 mol (rounded to five significant figures)
Now, we can calculate the heat released in the reaction using the formula from above:
q = m * C * ∆T
q = 0.667 g * 4.184 J/g°C * 108 °C
q ≈ 308.38 J (rounded to three significant figures)
Since the reaction involved 0.01663 moles of Ca, we can calculate the molar heat of reaction (ΔH_rxn) using the formula:
ΔH_rxn = q / moles of Ca
ΔH_rxn ≈ 308.38 J / 0.01663 mol
ΔH_rxn ≈ 18538.63 J/mol (rounded to four significant figures)
Therefore, the molar heat of reaction (∆H_rxn) for the given reaction is approximately 18538.63 J/mol.