What’s the complete thermochemical equation for this reaction : I have 1.95g Na2CO3, 125.0mL of 2.50 mol/L of HCl.Initial temperature is 20.7 degrees and the final temperature is 22.5 degrees. The balanced equation is 2HCl+Na2CO3 arrow 2NaCl+CO2+H2O
First, you need to calculate the moles of Na2CO3 and HCl involved in the reaction using the given masses and concentrations:
1. Calculate moles of Na2CO3:
Molar mass of Na2CO3 (sodium carbonate) = 105.99 g/mol
moles = mass / molar mass
moles = 1.95 g / 105.99 g/mol = 0.0184 mol Na2CO3
2. Calculate moles of HCl:
moles = volume (L) x concentration (mol/L)
moles = 0.125 L x 2.50 mol/L = 0.3125 mol HCl
The stoichiometry of the reaction tells us that 2 moles of HCl react with 1 mole of Na2CO3.
From the moles of Na2CO3 and HCl, we know that HCl is limiting:
HCl : Na2CO3 = 1 : 0.0184
Since the reaction ratio is 2 : 1, all the Na2CO3 will react along with 0.0184 x 2 = 0.0368 moles of HCl.
Now, calculate the heat change for the reaction using the temperature change and heat capacity of the system. Let's assume the specific heat capacity of the solution is 4.18 J/g°C.
q = mcΔT
q = (mass of solution x specific heat capacity of solution x temperature change)
q = 125.0 g x 4.18 J/g°C x 2.5°C
q = 1304.5 J
Now, convert joules to kilojoules:
q = 1304.5 J / 1000 = 1.3045 kJ
Finally, write the thermochemical equation for the reaction with the heat change included:
2HCl(aq) + Na2CO3(aq) → 2NaCl(aq) + CO2(g) + H2O(l) + 1.3045 kJ