NAME______PERIOD____DATE_____CHAPTER 11:THERMOCHEMISTRY What is Thermochemistry? Thermochemistry is the study of ______that occur during ______and physical changes of state. Temperature is the ______Kelvin is used in the SI system. ______is energy that transfers from one object to another because of temperature differences. It is represented by q. It is ENERGY stored in the structural units (bonds) of chemical substances. Heat flows from hot to cold

THERMODYNAMIC PROCESSES 1) ______: heat is absorbed by the system from the ______- container feels colder 2) ______: heat is released from the ______and absorbed by the surroundings- container feels warmer

3) ______: (Cp) is the heat energy required to raise the temperature of one gram of a substance by one degree Celsius Cp -is a physical, intensive property that is constant for a particular substance Cp -substances with higher heat capacities will absorb more energy than other substances

Different substances have different Cp (see Table 11.2 pg 296) THERMOCHEMISTRY Measuring and Expressing HEAT CHANGES Calculating heat COPY THE EQUATION: Explain terms.

o o  Problem1) How much heat does 100 g of iron absorb if it is heated from 20 C to 85 C? (cp = 0.46J/g oC) COPY THE SOLUTION

o o  Problem2) How much heat does 100 g of water absorb if it is heated from 20 C to 85 C? (cp = 4.18) COPY THE SOLUTION

 LABEL EACH PART OF THIS HEATING CURVE.

1.______2.______

3.______

4.______

5.______Calculating Heat Transfer

In problems 1-3, calculate the heat change (Joules) using the equations below

Heat (q) = Mass (m) x Specific Heat (C) x ∆ temperature

1. How many joules of heat are required to raise the temperature of 550 g of water from 12.0oC to 18.0oC? (remember the specific heat of water is 4.18 J/g x oC)

2. How much heat is lost when a 640 g piece of copper cools from 375oC, to 26oC? (The specific heat of copper is 0.385 J/g x oC)

3. The specific heat of iron is 0.444 J/g oC. How much heat is transferred when a large 2470 g slab of iron ingot is cooled from 880oC to 13oC?

In problems 4-5, find the mass using the equation below.

Mass (m) = Heat (q) ÷ (Specific Heat (C) x ∆ temperature)

4. How many grams of water would require 22,000 Joules of heat to raise its temperature from 34.0oC to 100.0oC? (Remember the specific heat of water is 4.18 J /g oC)

5. 8018 Joules of heat are applied to a piece of aluminum, causing a 56oC increase in its temperature. The specific heat of aluminum is 0.9 J/g oC. What is the mass of the aluminum?

In problems 6-7 find the temperature change, using the equation below.

∆ temperature = Heat (q) ÷ (Specific Heat (C) x Mass(m)

6. How many degrees would the temperature of a 450 g Slab of Iron ingot increase if 256 Joules of energy are applied to it? (The specific heat of iron is 0.444 J /g oC)

7. Copper has a specific heat of 0.385 J /g oC. How much change in temperature would the addition of 2052 Joules of heat have on a 538.0 gram sample of copper?

In problems 8-9 find the Specific Heat using the equation below.

Specific Heat (C) = Heat (q) ÷ (Mass (m) x ∆ temperature)

8. Determine the specific heat of a certain metal if a 450 gram sample of it loses 2100 Joules of heat as its temperature drops from 200oC to 97oC.

9. 347 Joules of heat are transferred to a 89.0 gram sample of an unknown material, with an initial temperature of 23.0oC. What is the specific heat of the material if the final temperature is 89.5oC?