Question

1. For each of your three trials state the following:

• heat needed to melt the ice (q)
• enthalpy of fusion
• percent error from the accepted enthalpy of fusion of water of 334 J/g
Answer:

Answer 1

The heat needed to melt ice (Q) is calculated using the formula Q = mLf, with the enthalpy of fusion (ΔHfus) for water being 334 J/g. To determine percent error, compare the experimental value with the accepted enthalpy value and apply the percent error formula. The heat value is positive because energy is absorbed during the endothermic process of melting.

Step-by-step explanation:

To calculate the heat needed to melt the ice (q), the formula Q = mLf is used, where m is the mass of the ice and Lf is the latent heat of fusion for water, which is 334 kJ/kg or 334 J/g. For example, if you had a trial with 3.00 g of ice, the heat needed, Q, would be calculated as Q = (3.00 g)(334 J/g) = 1002 J. To find the percent error from the accepted enthalpy of fusion of water, you would compare your experimental value to the accepted value of 334 J/g using the formula: Percent Error = |(Experimental Value - Accepted Value) / (Accepted Value)| × 100%.

For the enthalpy of fusion, ΔHfus, it is stated to be 334 J/g for water at 0°C. This is an endothermic process meaning that heat is absorbed by the ice as it melts, which is why the calculated heat, Q, is positive. The heat is positive instead of negative since energy is being supplied to the substance to induce the phase change from solid to liquid.

Answer 2

Trial 1: Heat needed: 22.0 Enthalpy of Fusion: 469 J/g Percent Error: 29% Trial

2: Heat needed: 18.0 Enthalpy of Fusion: 399 J/g Percent Error: 19%

Trial 3: Heat needed: 20.0 Enthalpy of fusion: 376 J/g Percent Error: 13%

Step-by-step explanation:

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