Make a model-melting ice on two blocks Make diagram that shows what is happening Explain why this is happening in the diagram

Calorimetry

Calorimeter qrxn = - (qwater) Calorimetry video Reaction at Constant P DH = qrxn Calorimetry video qrxn = - (qwater) No heat enters or leaves!

Specific heat at constant pressure Calculating heat Absorbed or released 𝑞=𝑚𝑠∆𝑇 Change in temperature 𝑇 𝑓 − 𝑇 𝑖 Unit: C Heat Unit: J or kJ Mass Unit: g Specific heat at constant pressure J/gC

Specific Heat = c Specific heat of a substance is the amount of heat required to raise the temperature of one gram of that substance by one degree Celsius. Unit for specific heat is J/goC

Heat capacity The amount of heat required to raise the system’s temperature by one Celsius.

Each substance has a different specific heat The lower the specific heat the lower the amount energy is required to raise its temperature.

Example 1 If the temperature of 56.6g of ethanol increases from 45.0°C to 80.0°C, how much heat has been absorbed by the ethanol? Specific heat of ethanol =2.44J/g°C

Example 2 A 4.00g sample of a substance was heated from 274K to 314K and absorbed 32J of heat, what is the specific heat of the substance?

Example 3 If 98,000 J of energy are added to 6200 g of water at 14.0C, what will the final temperature of the water be? Specific heat of water = 4.184 J/gC

Example 4 A 45.0g sample of metal is placed in boiling water until its temp. is 100.0C. a calorimeter contains 100.0g of water at a temp of 24.4C. the metal sample is removed from the boiling water and immediately placed in water in the calorimeter. The final temp of the metal and water in the calorimeter is 34.9C. assuming that the calorimeter provides perfect insulation, what is the specific heat of the metal?

Example 5 240g of water (initially at 21C) are mixed with an unknown mass of ion (initially at 501C). When thermal equilibrium is reached, the system has a temperature of 42 C. find the mass if the iron. Specific heat of iron = 0.449 J/gC

Example 6 240g of water (initially at 21C) are mixed with an unknown mass of ion (initially at 501C). When thermal equilibrium is reached, the system has a temperature of 42 C. find the mass if the iron. Specific heat of iron = 0.449 J/gC

Example 7 Determine the final temperature when a 25.0g piece of iron at 85.0C is placed into 75.0 grams of water at 20.0C.

Review Video-Crash Course Chemistry #19