Do Now

Write the answers to the following questions on your
Daily Organizer:
 Glass
has a specific heat capacity of 0.840 while silver
has a specific heat capacity of 0.240.
 Which
one has a greater specific heat capacity?
 What does that tell you about glass vs. silver?
 An
80-gram sample of brass decreases in temperature
from 64 °C to 49 °C. What was the heat energy lost by
the brass? Brass has a specific heat capacity of 0.380
J/g/°C.
Today’s Agenda
5 min
• Do Now
5 min
• Important Dates
5 min
• Quiz Review
40 min
• Quantity of Heat: Step Up
5 min
• Exit Ticket
Today’s Agenda
5 min
• Do Now
5 min
• Important Dates
5 min
• Quiz Review
40 min
• Quantity of Heat: Step Up
5 min
• Exit Ticket
Important Dates


Congrats to 4th period on highest quiz average!
Grade Notices Today
 If
missing news project, can complete an extra credit
one! These will be due the day before spring break.
 Absentee Policy



Lab Notebooks Due Friday
Homework This Week
Valentine’s Day Community Service
Today’s Agenda
5 min
• Do Now
5 min
• Important Dates
5 min
• Quiz Review
40 min
• Quantity of Heat: Step Up
5 min
• Exit Ticket
Today’s Agenda
5 min
• Do Now
5 min
• Important Dates
5 min
• Quiz Review
40 min
• Quantity of Heat: Step Up
5 min
• Exit Ticket
Calculating Energy


We can find the amount of thermal energy gained
or lost by any substance by using its specific heat
capacity, the mass of the substance and the
temperature change.
Q = mcΔT
 Positive
Q: object gained energy – there was an
increase in temperature (heated up)
 Negative Q: object lost energy – there was a decrease
in temperature (cooled down)
Review Problem 1

How much heat is needed to heat 150 grams of
silver from 5°C to 78°C? The specific heat capacity
of silver is 0.240 J/g/°C.
Review Problem 2

A sample of water gains 95 Joules of heat when it
heats up from 30°C to 50°C. What is the mass of
the water sample? The specific heat capacity of
water is 4.18 J/g/°C.
Review Problem 3

A 115-gram metal sample loses 164 J of heat
when its temperature decreases from 83 °C to 59
°C. What was the specific heat capacity of the
metal?
Example

A piece of metal with a specific heat of 0.430
J/g/°C and an initial temperature of 95°C is
placed in a calorimeter that holds 50 g of water.
The initial temp of the water is 25°C and the final
temp of the system is 40°C. What is the mass of
the metal?
1.
Start by finding the Q of the water.
 Use
2.
water’s mass, specific heat capacity & change in temp.
Set the Q of the metal equal to the -Q of the water!
 The
energy gained by water was lost by the metal so it’s
negative!
3.
Use this Q to find the mass of the metal.
 Specific
heat capacity & temperatures are given!
Practice Problem 1

A piece of metal with a specific heat capacity of
0.351 J/g/°C and an initial temperature of 45°C is
placed in a calorimeter that holds 60 g of water.
The initial temp of the water is 20°C and the final
temp of the system is 35°C. What is the mass of
the metal?

Hint
 Start
by finding the Q of the water.
 Set the Q of the metal equal to the -Q of the water!
 Use this Q to find the mass of the metal.
Practice Problem 2

A 15 gram piece of metal with a temperature of
100°C is placed in a calorimeter that holds 40 g of
water. The initial temp of the water is 10°C and the
final temp of the system is 50°C. What is the
specific heat capacity of the metal?
 Hint
 Start
by finding the Q of the water.
 Set the Q of the metal equal to the -Q of the water!
 Use this Q to find the specific heat capacity of the metal.
Practice Problem 3

A 25 gram piece of metal with a temperature of
75.0°C is placed in a calorimeter that holds 50.0 g
of water. The initial temp of the water is 19.6°C
and the final temp of the system is 25.0°C. What is
the specific heat capacity of the metal?
 Hint
 Set
the Q of the metal equal to the -Q of the water!
Challenge Problem

A 10 gram piece of metal with a specific heat of
0.670 J/g/°C is placed in a calorimeter that holds
30 g of water. The initial temp of the water is
65°C and the final temp of the system is 20°C.
What is the initial temperature of the metal?
 Hint
 This
works the same as the other problems except you’re
finding the initial temp of the metal!
Independent Practice
Complete the two practice problems. When
finished, I will check it & give you an exit ticket.
After you finish, feel free to work on homework
or Capstone 
Today’s Agenda
5 min
• Do Now
5 min
• Important Dates
5 min
• Quiz Review
40 min
• Quantity of Heat: Step Up
5 min
• Exit Ticket