q = mx Cp x ΔT

Matter and Energy Transfer

Radiation
Transfer of energy via electromagnetic waves.
examples:
-sun warms your face
-apparent heat of a fire

Conduction
Heat transfer through molecular motions .
from warm to cold

Convection
Energy transfer through mass movement of a
substance
Substance is either a liquid
or a gas…

All three….

QUESTIONS ABOUT READING
Fold your paper into threes..
Number each section #1- #6
Write your name at the top

q = m x Cp x ΔT
Answer One and Pass It Along
q = Energy and is measured in units such as
joules, calories, kilocalories or Calories
1. What does ΔT measure and what units
can/should be used

q = m x Cp x ΔT
Answer One and Pass It Along
Cp = Specific Heat and measured commonly in a unit
such a Joule/gram x o Celsius or J/g o C
(sometimes in cal/g o C or kcal/g o C )
What informa;on does the specific heat of a substance tell you about that material
2. List from Highest to Lowest expected
Specific Heat values:
Metal Wood Water

Answer One and Pass It Along
q = m x Cp x ΔT
q = Energy and is measured in units such as joules,
calories, kilocalories or Calories
3. Determine the specific heat of an
unknown metal that required 2.56 kcal of
heat to raise the temperature of 150.00 g
from 15.0 o C to 200.0 o C

q = m x Cp x ΔT
Answer One and Pass It Along
What does the sign on q tell you
4. Which part of this statement is NOT
true Correct the statement.
When a hot poker s;ck is immersed in
water the s;ck is endothermic and should
have a value of +q because it is
transferring its’ heat to the water.

q = m x Cp x ΔT
Answer One and Pass It Along
-­‐q hot
= q cold
5. Iron metal has a specific heat of 0.449 J/g o C. How much heat
is transferred to a 5.00 g piece of iron, ini;ally at 20.0 o C, when
it is placed in a beaker of boiling water at 1 atm
a. Which is exothermic, the water or iron
b. Why is it important in the ques;on to
know that the water was boiling

q = m x Cp x ΔT
Answer One and Pass It Along
6. Iron metal has a specific heat of 0.449 J/g o C. How many
calories of energy are given off to lower the temperature of
100.0 g of iron from 150.0 o C to 35.0 o C
a. Since the temperature of of the iron is
decreasing, is it endothermic or
exothermic
b. Why is it important to note the answer
is requested in calories

RETURN TO RIGHTFUL OWNER
Wonder how you did
How well did your classmates
understand the homework

q = m x Cp x ΔT
q = Energy and is measured in units such as
joules, calories or Calories
1. What does ΔT measure and what units
can/should be used
Δ means change... change in temperature
calculated by T final -­‐ T ini>al ( o C or o K)

q = m x Cp x ΔT
Cp = Specific Heat and measured commonly in a unit
such a Joule/gram x o Celsius
What informa;on does the specific heat of a substance tell you about that material
-­‐ How difficult or easy it is to heat up or cool down..
2. List from Highest to Lowest expected
Specific Heat values:
Water (4.18 J/g o C) Wood (1.2 -­‐2.3 J/g o C) Metal (

q = m x Cp x ΔT
q = Energy and is measured in units such as joules,
calories, kilocalories or Calories
3. Determine the specific heat of an unknown metal that required 2.56 kcal of heat to
raise the temperature of 150.00 g from 15.0 o C to 200.0 o C
q = m x Cp x (Tfinal - Tinitial)
2.56 kcal = 150.00g x Cp x (200.0 o C - 15.0 o C)
2.56 kcal = 150.00g x Cp x (185.0 o C)
2.56 kcal / (150.00g x 185.0 o C) = Cp
2.56 kcal / (150.00g x 185.0 o C) = Cp
9.2 x 10 -5 kcal /g o C = Cp

q = m x Cp x ΔT
What does the sign on q tell you
Heat is released (exothermic) or taken in (endothermic).
4. Which part of this statement is NOT true Correct the statement.
When a hot poker s;ck is immersed in water the s;ck is endothermic and should have
a value of +q because it is transferring its’ heat to the water.
When a hot poker s;ck is immersed in water the s;ck is endothermic and should have
a value of +q because it is transferring its’ heat to the water.
When a hot poker s;ck is immersed in water the s;ck is exothermic and should have a
value of -­‐q because it is transferring its’ heat to the water.

q = m x Cp x ΔT
-­‐q hot
= q cold
5. Iron metal has a specific heat of 0.449 J/g o C. How much heat is transferred to a 5.00 g piece of iron,
ini;ally at 20.0 o C, when it is placed in a beaker of boiling water at 1 atm
a. Which is exothermic, the water or iron
b. Why is it important in the ques;on to know that the water was boiling
Water is giving heat to Iron metal, therefore water is exothermic
q = m x Cp x (Tfinal - Tinitial)
q = 5.00g x 0.449 J/g o C x (Tfinal - 20.0 o C)
Boiling water means the final temp of iron = 100 o C

5. Iron metal has a specific heat of 0.449 J/g o C. How much heat is transferred to a 5.00 g piece of iron,
ini;ally at 20.0 o C, when it is placed in a beaker of boiling water at 1 atm
a. Which is exothermic, the water or iron
b. Why is it important in the ques;on to know that the water was boiling
q = m x Cp x (Tfinal - Tinitial)
q = 5.00g x 0.449 J/g o C x (Tfinal - 20.0 o C)
q = 5.00g x 0.449 J/g o C x (100.0 o C - 20.0 o C)
q = 5.00g x 0.449 J/g o C x (80.0 o C)
q = 179.6 (what unit)
q = 5.00g x 0.449 J/g o C x (80.0 o C)
q = 5.00g x 0.449 J/g o C x (80.0 o C)
q = 179.6 Joules = 180 J

q = m x Cp x ΔT
6. Iron metal has a specific heat of 0.449 J/g o C. How many calories of energy are given off to lower the
temperature of 100.0 g of iron from 150.0 o C to 35.0 o C
a. Since the temperature of of the iron is decreasing, is it endothermic or exothermic
b. Why is it important to note the answer is requested in calories
a. Exothermic (losing heat)
b. Specific Heat uses Joules therefore a conversion is
required. q = m x Cp x (Tfinal - Tinitial)
q = 100.0g x 0.449 J/g o C x (35.0 o C - 150.0 o C)
q = 100.0g x 0.449 J/g o C x (-115.0 o C)
q = -5,163.5 unit q = -5,163.5 Joules
-5,164 Joules 1 calorie
1 4.18 Joules
= -1235 cal = -1.23 x10 3 cal
energy given off (negative value)