71 Days Until the Harvard Westlake Final • Catalyst: 1. What is entropy?

2. What is the triple point on a phase diagram?

3. What is the critical point on a phase diagram?

End

Today’s Learning Target • 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?

Specific Heat • The amount of energy that is transferred to a material is dependent on the nature of the material receiving the energy.

• Specific Heat – The amount of energy required to raise the temperature of one gram of substance one degree Celsius • Represent by the symbol C p

Calorimetry  • Calorimetry is the science of measuring the heat of a chemical reaction .

q



m



c p

 

T

• q represents the heat gained/released • C p is the specific heat • ΔT = Final Temperature – Initial Temp.

• If we can measure the mass and temperature, then we can determine the heat gained/lost in a reaction

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/ o C. How much heat is needed to change the temperature of a 30 g sample of copper from 20.0 o C to 60.0 o C?

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.

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 o C.

• 1000 calories = 1

C

alorie • 1 serving of Cheetos has 140 Calories

SUMMARIZE

Lab Intro • Info about lab procedures and equipment.

Lab Work Time

Lab Calculations

Work Time • Begin working on your “Homework 7.3” • There will be an exit slip after this activity

Learning Log Assessment Rate yourself 1 – 4 on LTs 7.6

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

Learning Log Assessment Using your exit slip score, re-rate yourself on LTs 7.6

Closing Time • Homework 7.3 – Calorimetry Calculations • Rough Draft of Lab Report DUE TOMORROW