Energy and Heat — Energy Changes Within One Phase

Contrast temperature and heat below:

SPECIFIC HEAT (c) is a measure of

Specific heat is defined as

If specific heat is high, the substance will stay

Write the equations here:Identify the variables and their units here:

SPECIFIC HEAT VALUES OF COMMON SUBSTANCES AT 20°C (J/g°C)

Air / 1.00 / Ethyl Alcohol, C2H5OH / 2.45 / Mercury / 0.139
Aluminum / .895 / Fluorine / 0.824 / Nickel / 0.443
Asbestos / 2.66 / Gold / 0.129 / Paraffin / 2.9
Calcium / .652 / Granite / 0.803 / Platinum / 0.134
Carbon (diamond) / .502 / Hydrogen / 14.3 / Silver / 0.233
Carbon (graphite) / .711 / Ice / 2.06 / Stainless Steel / 0.51
Carbon dioxide / .832 / Iron / 0.448 / Steam / 02.02
Chlorine / 0.477 / Lead / 0.128 / Tin / 0.220
Copper / 0.387 / Magnesium / 1.01 / Water / 4.18

Ex1: How much heat is required to raise the temperature of a 50.0 mL sample of water from 25.0°C to 85.0°C?

Ex 2: What mass of silver is present if it requires 225 Joules of heat to increase the temperature from 13.5°C to 45.0°C?

Ex 3: Calculate the specific heat of lead if 62.3 J are added to 11.5 g of lead and the temperature increases from 20.2°C to 62.5°C.

Energy and Heat — Energy Changes At One Temperature

Heat of Fusion (Hf) –

The heat needed to

Heat of Vaporization (Hv) –

The heat needed to

  • Which will require more energy, loosening or breaking IMFs?
  • Which will be higher, Hf or Hv?
  • Which line on the heating curve will be longer, melting or vaporizing?

Write the equations here: Identify the variables and their units here:

Table of Heats of Fusion and Vaporization

SUBSTANCE / HEAT OF FUSION
(J/g) / HEAT OF VAPORIZATION
(J/g)
Copper / 205 / 4726
Ethyl alcohol, C2H5OH / 109 / 879
Gold / 64.5 / 1578
Silver / 88 / 2300
Water / 334 / 2260

Ex 1: How much heat must be added to 75 g of water at 100°C to boil it?

Ex 2: If 1500 J of heat energy are added to a block of ice, how many grams of ice will melt?

Heat and Energy Homework

Show all work WITH UNITS! Remember… no work = no credit!

Use q = mcΔT

  1. How much heat is required to raise the temperature of 40.0 g of aluminum from 50.0°C to 90.0°C?
  1. How much heat is required to raise the temperature of 1.248 kg of gold from 22.0°C to 45.0°C?
  1. Calculate the specific heat for air if 1500.0 Joules are required to raise the temperature of 50.0 g from 0.0°C to 40.0°C.
  1. Calculate the specific heat for sea water if 13,650 Joules are required to raise the temperature of 500.0 mL from 28.0°C to 35.0°C. (Density of sea water is 1.027 g/mL)
  1. 100.0 g of water was heated in a calorimeter and 1674.5 Joules were gained by the water. If the initial temperature was 18.0°C, what was the final temperature of the water?

Use q = mHfor q = mHv

  1. How much heat is needed to boil 542 mg of ethyl alcohol?
  1. How much heat is released when 100 grams of steam is condensed to water?
  1. What is the heat of fusion for gold if 5483 J of heat are necessary to melt 0.085 kg?
  1. How much heat energy is required to melt 85.0 g of silver metal?
  1. What mass of copper can be melted by the addition of 2500 J of heat energy?