Catalyst1. What is entropy?2. What is the triple point on a phase diagram?3. What is the critical point on

a phase diagram?

End

Learning Log AssessmentRate yourself 1 – 4 on LTs 7.1-7.6

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Lecture 7.4 – Calorimetry and the hot cheetos lab

Today’s Learning Target• LT 7.6 – Using calorimetry data, I can utilize

my knowledge of temperature change and specific heats to calculate the amount of heat transferred for a reaction.

Today’s Focus Question• How do we determine the amount of calories

in Flamin’ Hot Cheetos?

How is the energy of food measured?

(Review) I. Specific Heat• The amount of energy that is transferred is

dependent on the nature of the material receiving the energy.

• Specific Heat (Cp) – The energy required to raise the temperature of one gram of substance one degree Celsius

(Review) II. Calorimetry• Calorimetry is the science of measuring the

heat of a chemical reaction.

• q represents the heat gained/released• Cp is the specific heat

• ΔT = Final Temperature – Initial Temp.

Class Example• A 4.0 g sample of glass is heated from 274 K to

314 K. Glass has a specific heat of 0.20 J/(g x K). How much heat is gained during this heating?

Table Talk• The specific heat of copper is 0.4 J/oC. How much

heat is needed to change the temperature of a 30 g sample of copper from 20.0 oC to 60.0 oC?

Stop and Jot• Determine the specific heat of a material if a 35 g

sample absorbed 96 J as it was heated from 293 K to 313 K.

SUMMARIZE

Calories in Flamin’ Cheetos• Q can be measured in calories• Food scientists measure the calories contained

within food by measuring the amount of energy it takes to raise 1 g of water 1 oC.

• 1000 calories = 1 Calorie• 1 serving of Cheetos has 140 Calories

Flamin Hot Cheetos Lab

Lab Work Time

Lab Calculations

• Continue working on your Hot Cheetos Lab• There will be an exit slip after this activity

Work Time

1. I have a sample of water and I increase the temperature from 10.0 oC to 40 oC. The specific heat of water is 4.18 J/(g x oC). Calculate the heat absorbed for this process.

Exit Slip

Learning Log Assessment

Rate yourself 1 – 4 on LTs 7.1-7.6

• Finish Hot Cheetos Lab and Update Wikispaces• Rough Draft of Lab Report Begins

Closing Time