| Question. A solid has a melting point of 90.0∘ C. Calculate the total heat required to change 2.5 kg of this solid from 40.0∘ C to a liquid, given that the specific heat of the solid is 390 J/kg-K and its heat of fusion is 4000 J/kg. Show your work and explain your reasoning. |
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| Earlier response (step 30) | Later response (step 105) |
| To determine the total heat required to change 2.5 kg of a solid from 40.0 ∘ C to a liquid, we need to account for two distinct processes: 1. Heating the solid from its initial temperature to its melting point 2. Melting the solid at its melting point into a liquid | To calculate the total heat required to change 2.5 kg of a solid from 40.0 ∘ C to a liquid, we need to consider two distinct processes: 1. Heating the solid from its initial temperature (40.0 ∘ C) to its melting point (90.0 ∘ C). 2. Melting the solid at its melting point (90.0 ∘ C) into a liquid. |
| Step 1: Heating the solid to its melting point The temperature difference between the initial temperature and the melting point is: ΔT=90.0∘C−40.0∘C=50.0∘C The heat required to raise the temperature of the solid is calculated using the specific heat formula: Q1=m⋅c⋅ΔT Where: ∙ m=2.5kg ∙ c=390J/kg⋅K ∙ ΔT=50.0K (since a change of 1 ∘ C = 1 K) Q1 =2.5kg⋅390J/kg⋅K⋅50.0K =48750J | Step 1: Heat Required to Raise the Temperature of the Solid The formula for the heat required to change the temperature of a substance is: Q1=m⋅c⋅ΔT Where: ∙ m=2.5kg (mass of the solid), ∙ c=390J/kg-K (specific heat of the solid), ∙ ΔT=Tmelt−Tinitial =90.0∘C−40.0∘C=50.0∘C . Q1 =2.5kg×390J/kg-K×50.0K =48,750J |
| Step 2: Melting the solid at its melting point The heat required to melt the solid is calculated using the heat of fusion formula: Q2=m⋅Lf Where: ∙ m=2.5kg ∙ Lf=4000J/kg Q2 =2.5kg⋅4000J/kg =10000J | Step 2: Heat Required to Melt the Solid The formula for the heat required to melt a substance is: Q2=m⋅Lf Where: ∙ m=2.5kg (mass of the solid), ∙ Lf=4000J/kg (heat of fusion). Q2 =2.5kg×4000J/kg =10,000J |
| Step 3: Total Heat Required Qtotal =Q1+Q2 =48750J+10000J =58750J | Step 3: Total Heat Required Qtotal =Q1+Q2 =48,750J+10,000J =58750J |
| Final Answer 58750 | Final Answer 58750J |