Bell Ringer
Balance the following combustion reaction. Also, name
the hydrocarbon and draw the hydrocarbon structure.
Do Now
You heat a balloon filled
with air. What do you think
happens to the pressure
inside of the balloon? Why?
By the end of the day
today, SWBAT…
• Explain and calculate
specific heat
Why it matters in LIFE:
Explains why certain
objects are made out of
certain materials
Why it matters in THIS
CLASS: It connects
everything we have done
thus far in quarter 3– you
will have a mastery quiz on
__Specific Heat__ so let’s hit
Specific Heat

Specific heat is a property of matter that describes
the amount of energy required to raise the
temperature of one gram of a substance by 1 °C
Specific Heat



Specific heat is a constant that relates heat and
temperature change per kilogram
Different materials have a different specific heat
A low specific heat means heat is conducted
through an object quickly
Specific Heat
CONDUCTORS: change heat easily
Low Specific Heat
Require little energy to change temp
INSULATORS: Do NOT change heat easily
High Specific Heat
Require LOTS of energy to change temp
Example! Aluminum vs. Stainless Steel




Low specific heat capacity = substance needs less
heat substance needs to get hot
High specific heat capacity = substance needs more
heat a substance needs to get hot
Aluminum is 0.9 J/kg C
Stainless steel is 0.5 J/kg C
Material
C (J/kg-C)
Water
4184
Plastic Foam
2010
Air, 200 K
1650
Aluminum
897
Iron
449
Brass
375
Conductors
Insulators
Specific Heat
Specific Heat Demo

I have two balloons – one filled with water and one
filled with air
What should happen to
the balloon?
Specific Heat Demo



Why did the balloon filled with water not explode?
The water balloon does not explode because the
water inside absorbs the heat better than the air
does
Water has a HIGHER specific heat, which means it
has a HIGH heat capacity
 It
takes a lot more energy to change the temperature
of the water than it does for the air
Specific Heat – Equation
Q = mCDT
Q = mC(Tf – Ti)
Q = heat (joules-J)
m = mass (kg)
C = specific heat (J/kg C)
DT = change in temp (C)
Example 1  Q = mCDT

If the specific heat of methanol is 251 J/kg-˚C, how
many Joules of heat are needed to raise the temp
of 0.250 kg of methanol from 18˚C to 33˚C?
Example 2  Q = mCDT

How much does a piece of ice weigh if it
absorbs 200 J of heat when it is melted from
0˚C to 25˚C?
Group Practice — Area 1

A .625 kg sample of water was cooled from 50˚C
to 10˚C. How much heat was lost? The specific heat
of water is 4,184 J/kg-˚C.
Group Practice — Area 2

The heat capacity of lead is 130 J/kg-˚C. How
much heat (in J) is required to raise the temperature
of 0.015 kg of lead from 22˚C to 37˚C?
Group Practice — Area 3

What is the specific heat of a substance that
absorbs 250 J of heat when a sample of 10 kg of
the substance increases in temperature from 10˚C to
70˚C?
Classwork


Work a s group to complete the class work activity.
This is the time to ask questions and try to get a
better understanding of this topic.
Exit Slip Expectations



Complete the exit ticket questions INDEPENDENTLY
You are not getting enough INDIVIDUAL practice
before assessments, which is one of the reasons why
the grades are so low
You don’t really know it unless you can do it ON
YOUR OWN
Exit Slip

The specific heat of SrCl2 is 0.5 J/gC. How much
heat is needed to change the temperature of a 20
gram sample of SrCl2 from 10˚C to 20˚C?
Specific Heat Quiz
1. When 3.0 kg of water is warmed from 10.0°C to
80.0°C, how much heat energy is needed?
2. 1960 J of heat are added to 500. g of copper taking
its temperature from 25.0 ºC to 35.1ºC. What is the
specific heat capacity of copper?
3. Calculate the temperature change when 10,000.0 g
of water loses 232,000 J of heat.