Exactly .203g of zinc metal is dissolved in dilute HCl(aq) in an ice calorimeter. The heat released melts enough ice to produce a volume change of 0.254mL in the ice water mixture surrounding the reaction vessel. Calculate the enthalpy change per mole of zinc for the reaction:
Zn(s) +HCl(aq)→Zn2+(aq) +H2(G)
heat for ice melting=254*Hf
Hf=above*molmassZn/.203
disregard last line
delta H= heatfor ice melting*molmass/.203
To calculate the enthalpy change per mole of zinc for the reaction, we can use the equation:
ΔH = q/n
where ΔH is the enthalpy change per mole, q is the heat released or absorbed during the reaction, and n is the number of moles of zinc.
First, we need to calculate the heat released or absorbed during the reaction using the calorimetry data. We know that the heat released is equal to the heat absorbed by the ice water mixture. Since we have a volume change of 0.254 mL, we can calculate the heat absorbed by the ice water mixture using the equation:
q = m * ΔT * C
where q is the heat absorbed, m is the mass of the ice water mixture, ΔT is the change in temperature, and C is the specific heat capacity of the ice water mixture.
Since the reaction takes place in an ice calorimeter, we assume that the density of the ice is equal to 1 g/mL. Therefore, the mass of the ice water mixture can be calculated as:
m = V * density
m = 0.254 mL * 1 g/mL
m = 0.254 g
Next, we need to determine the change in temperature, ΔT. Since the reaction is occurring in an ice calorimeter, the temperature change is due to the melting of the ice. The enthalpy change associated with melting ice is 6.02 kJ/mol. Thus, we can calculate the change in temperature using the equation:
ΔT = q / (m * C)
where C is the specific heat capacity of the ice water mixture. Assuming a specific heat capacity of 4.18 J/g·°C for water, we convert this to kJ/g·°C:
C = 4.18 J/g·°C / 1000 = 0.00418 kJ/g·°C
Plugging in the values, we can solve for ΔT:
ΔT = q / (m * C)
ΔT = 6.02 kJ/mol / (0.254 g * 0.00418 kJ/g·°C)
ΔT ≈ 563.35 °C
Finally, we can calculate the enthalpy change per mole of zinc using the formula:
ΔH = q / n
Since we're given that 0.203 g of zinc is used, we need to determine the number of moles of zinc:
n = mass / molar mass
n = 0.203 g / (65.38 g/mol) (molar mass of Zn)
Plugging in the values, we get:
n ≈ 0.003110 mol
Now we can calculate the enthalpy change per mole of zinc:
ΔH = q / n
ΔH = 6.02 kJ/mol / 0.003110 mol
ΔH ≈ 1936.6 kJ/mol
Therefore, the enthalpy change per mole of zinc for the reaction is approximately 1936.6 kJ/mol.