Joules and Water

Fahrenheit (°F) Celsius (°C) Kelvin (K) Fill in the chart below using your Earth Science Reference Tables.Earth Science Reference Tables

 CHANGES OF THE STATE OF WATER A. Three states of matter 1. Solid 2. Liquid 3. Gas B. To change state, heat must be either absorbed or released (latent heat) C. Heat energy 1. Measured in Joules – heat necessary to raise the temperature of 1 gram of water 1 degrees Celsius 2. Latent heat a. Stored or hidden heat b. Not derived from temperature change c. Important in atmospheric processes

D. Processes involving change of state & latent heat 1. Evaporation a. Liquid changed to a gas (Energy Absorbed) b joules per gram of water added (latent heat of vaporization) 2. Condensation a. Water vapor (gas) changed to a liquid (Energy Released) b. latent heat of conden joules per gram lost 3. Melting a. Solid changed to a liquid (Energy Absorbed) b. 334 joules per gram of water added (latent heat of melting) 4. Freezing a. Liquid changed to a solid (Energy Released) b. latent heat of fusion- 334 joules per gram lost

(cont.) 5. Sublimation a. Solid changed directly to a gas (ex: ice cubes shrinking in the freezer) 6. Deposition a. Water vapor changed to a solid (ex: frost in the freezer) water lost

solid liquid gas vaporization (+2260 Joules) condensation ( Joules ) melting (+334 joules) solidification (- 334 joules ) Heat added Temperature ( o C) Heating Curve for Water Heat lost Draw the graph of water heating. Label the following terms in their correct places: condensation, vaporization, solidification, melting.

Properties of Water ► ► Heat energy gained during melting J/g ► ► Heat energy released during freezing J/g ► ► Heat energy gained during vaporization J/g ► ► Heat energy released during condensation J/g ► ► Density at 3.98°C g/mL

Check the box which describes whether energy is gained or lost for each process. ProcessEnergy Gained Energ y Lost Condensation Evaporation Melting Solidification ProcessJoules Gained Joules Lost Condensation Evaporation Melting Solidification

the amount of energy required to raise the temperature of 1 gram of a substance 1°C Please go to Page 1 of the Earth Science Reference TablesEarth Science Reference Tables.

Why does water heat up and cool down slower than land? it has a higher specific heat

If you heated equal masses of basalt and lead, which one would record a faster increase in temperature? Explain how you know. the lead because it has a lower specific heat

Which Earth material has the greatest specific heat?

LATENT HEAT PROBLEMS 1. How many joules does it take to heat up 10 gram of basalt 3 degrees C 25.2 joules 2. How many joules does it take to heat up 50 gram of cooper 15 degrees C 285 joules 3. How many joules does it take to change 12 grams of ice to liquid 4008 joules 4. How many joules does it take to change 4 grams of water to vapor 9040 joules 5. How many joules does it take to change 18 grams of liquid to ice joules

 HUMIDITY A. Amount of water vapor in the air 1. Saturated air is filled to capacity 2. Capacity is temperature dependent – warmer air has much greater capacity B. Measurements of humidity 1. Relative humidity a. Ratio of Actual water vapor content, to Potential water vapor capacity, At a given temperature b. Expressed as a percent c. Saturated air 1. Vapor content equals water vapor capacity % relative humidity d. Can be changed in two ways

(cont.) 1. Add or subtract moisture from the air a. adding raises the relative humidity b. removing lowers the relative humidity 2. Changing air temperature a. lowering raises the relative humidity b. raising lowers the relative humidity e. Daily variations in temp. and rel. hum. 1. early morning (low temp. & high rel. hum.) 2. mid afternoon (high temp. & low rel. hum.)

e. Dew point 1. Temperature where air is saturated & relative humidity is 100% 2. Cooling air below the dew point causes condensation a. Cloud formation is a result of this b. Water vapor requires a surface to condense on called condensation nuclei. ex Dirt dust salt f. Instruments used to measure humidity 1. Sling Psychrometer a. Compares temperature of 1. Wet-bulb thermometer 2. Dry-bulb thermometer b. If air is saturated (100% relative humidity) 1. Both thermometers read the same temperature

Determine Dew Point Find the Dry Bulb Temperature Of 10° The Wet Bulb was 6° What was the Depression ? 4° The Dew Point is 1 °

Dry bulb 20 Dewpoint 14 Diference between 4 Wet bulb 16 Dry bulb 10 Dewpoint 1 Difference between 4 Wet bulb 6 Dry bulb 15 Dewpoint 10 Difference between 3 Wetbulb 12 Dewpoint problems

Relative Humidity Dry bulb 20 Rel. humidity 51 Difference between 6 Wet bulb 14 Dry bulb 26 Rel. humidity 100 Difference between 0 Wet bulb 26