Topic B PDF

Unit B: Energy Flow in Global Systems Section 2: Global Energy Transfer Let’s Review… Well, at least this is inspiring artists…  Let’s look at some climate charts! We love charts!  Where does ALL of our energy come from? Solar energy – Radiant energy – Transmitted as ele...

Unit B: Energy Flow in Global Systems Section 2: Global Energy Transfer Let’s Review… Well, at least this is inspiring artists…  Let’s look at some climate charts! We love charts!  Where does ALL of our energy come from? Solar energy – Radiant energy – Transmitted as electromagnetic wavelengths in a spectrum – Regions of Earth do NOT receive same amount of solar energy  Insolation The amount of solar energy received by a region of Earth’s surface – Amount of energy per area Determines the region’s climate – Ex. Equator is much warmer than the poles  Insolation World solar insolation map  Angle of Inclination Earth’s poles have an axial tilt in its orbit around the sun – Angle of inclination = 23.5° – Determines the seasons  Latitudes Latitudes – Imaginary lines running parallel to the equator – Equator = 0° North pole = 90° N South pole = 90° S Angle of inclination → different hours of daylight at different latitudes  Latitudes Solstice → when the two poles are tilted most toward and away from the sun Equinox → number of daylight hours = nighttime hours  Angle of Incidence Angle between sun’s ray on a surface and a line perpendicular to the surface ↑ angle of incidence → ↑spread of sun’s radiation → ↓ energy intensity per area → ”less direct” sunlight  Angle of Incidence A major determining factor of climate Equator → pole = ↓ insolation  Albedo Solar radiation is either reflected or absorbed – Reflection → cooling – Absorption → warming Albedo → amount of solar radiation reflected by a surface – Light-coloured surfaces = high albedo  Natural vs. Man-Made Greenhouse Effect Greenhouse gases → gases that help absorb and retain thermal energy from the sun – Ex. Water vapour, CO2, CH4, N2O  Thermal Energy Transfer Thermal energy moves from an area of high temperature to and area of low temperature Methods – Radiation → emission of energy as particles or waves Can be reflected/absorbed – Conduction → transfer by direct contact Usually in solids – Convection → transfer by particles moving from one location to another Usually in fluids (liquids and gases) Thermal Energy Transfer Thermal Energy Transfer + Atmosphere  Atmosphere Pressure Pressure exerted by the mass of air above any point on Earth’s surface Warm air is less dense than cold air → warmer air rises → warmer regions of the atmosphere exert less atmospheric pressure than the cooler regions Wind → movement of cool air from areas of high pressure to areas of low pressure  Coriolis Effect Deflection of any object from a straight line path by the rotation of the Earth Causes moving air or wind to turn right in the Northern Hemisphere and left in the Southern Hemisphere Coriolis Effect Coastal Breeze  Specific Heat Capacity These cities have similar insolation → why do they have different seasonal temperature? What are the regions like? (Land-locked? Warm ocean currents? Cold ocean currents?) Thermal Energy Transfer in the Hydrosphere  Specific Heat Capacity Specific heat capacity (c) → the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius – Unit = joule/g · ℃ Substances with large heat capacity – Takes more energy to raise temperature Heats up slowly – Large amount of energy needed to be released when temperature decreases Cools down slowly  Specific Heat Capacity Water → c = 4.19 J/g · ℃ Air → c = 1.020 J/g · ℃ Does this explain the climate difference between Lethbridge, Vancouver, and Gander? Thermal Energy Transfer in the Hydrosphere  Quantity of Thermal Energy, Q Amount of thermal energy absorbed or released when temperature of a certain mass of substance changes – Q = mcΔT Q → Quantity of thermal energy (J) M → mass of a substance (g) C → specific heat capacity of substance (J/g · ℃) ΔT → change in temperature (℃) Ex. A 50.0-g mass of water at 25.0°C is heated to 50.0°C on a hot plate. Given that the theoretical specific heat capacity of water is 4.19 J/g · ℃, determine the value for Q.  Let’s Try Ex. A 200-g mass of water at 4.00°C is allowed to warm to 22.0°C. Determine the amount of thermal energy, Q, absorbed. The theoretical specific heat capacity of water is 4.19 J/g · ℃. Ex. How much thermal energy must be released to decrease the temperature of 1.00 kg of water by 10.0°C?  Let’s Try Ex. Determine the quantity of energy required to warm a 1.00-kg block of ice from -15.0°C to 0°C. Ex. Calculate the change in temperature, ΔT, that occurs when 8.38 kJ of thermal energy is added to 100.0 g of water.  Let’s Try Ex. Calculate and compare the changes in temperature, Δt, that occur when 500 J of thermal energy is removed from 1.00 kg of water, and when 500 J of thermal energy is removed from 1.00 kg of iron. The theoretical specific heat capacity of water is 4.19 J/g · ℃, and the theoretical specific heat capacity of iron is 0.449 J/g · ℃. When 574 J of thermal energy is added to 20.0 g of aluminium, the temperature of the aluminium increases by 32.0°C. What is the experimental specific heat capacity of aluminium?  Let’s Try Ex. Calculate the experimental specific heat capacity of an object of mass 1.00 kg, given that the object releases 1.95 kJ of heat when its temperature decreases by 15.0°C.  The Hydrologic (Water) Cycle In the biosphere, water molecules constantly move through the hydrologic cycle in different phases – Liquid water (including in cells/tissues of living organisms) – Solid ice – Water vapour  Phase Change vs. Thermal Energy Phase change → release or absorption of thermal energy BUT temperature stays the same during the process – Heat is absorbed Solid → liquid Liquid → gas – Heat is released Gas → liquid Liquid → solid  Phase Change vs. Molecule Attraction Energy is absorbed to break attractive bonds between molecules – Solid → liquid – Liquid → gas Energy is released when attractive bonds are formed between molecules – Gas → liquid – Liquid → solid  Heat of Fusion (Hfus) Amount of thermal energy (heat) absorbed when 1 mole of a substance changes from solid to liquid – Hfus → heat of fusion (kJ/mol) – Q → quantity of themal energy (kJ) – n → amount of substance (mol) Theoretical heat of fusion of ice 6.01 kJ/mol  Let’s Try Ex. When 27.05 kJ of thermal energy is added to 4.50 mol of ice at 0.0°C, the ice melts completely. What is the experimental heat of fusion of water? Ex. Given the theoretical Hfus of ice is 6.01 kJ/mol, how much thermal energy is required to completely melt 3.20 mol of ice at 0.0°C? Ex. Given the theoretical Hfus of ice is 6.01 kJ/mol, calculate the amount in moles of ice at 0.0°C that can be melted by addition of 15.0 kJ of thermal energy.  Let’s Try Ex. When 5.00 g of ice melts, 1.67 kJ of thermal energy is absorbed. Calculate the experimental heat of fusion of ice in this case. Ex. Determine the experimental heat of fusion of copper, given that it takes 0.606 kJ of thermal energy to melt 100 g of solid copper at its melting point.  Heat of Vaporization (Hvap) Amount of thermal energy (heat) absorbed when 1 mole of a substance changes from liquid to gas – Hvap → heat of vaporization (kJ/mol) – Q → quantity of themal energy (kJ) – n → amount of substance (mol) Theoretical heat of vaporization of water 40.65 kJ/mol  Let’s Try Ex. When 150 g of water changes from liquid to vapour phase, 339 kJ of energy is absorbed. Determine the experimental heat of vaporization of water. Ex. When 8.70 kJ of thermal energy is added to 2.50 mol of liquid methanol (CH3OH), all the methanol enters the vapour phase. Determine the experimental heat of vaporization of methanol. Ex. Calculate the amount of thermal energy required to change 500 g of water from the liquid phase to the vapour phase. The molar mass of water is 18.02 g/mol, and the theoretical heat of vaporization of water is 40.65 kJ/mol.  Hfus and Hvap vs. Global Energy Transfer Evaporative cooling – Liquid water evaporating → absorbs 40.65 kJ of energy per mole from surrounding Ex. Large bodies of water → surrounding cools – Water vapour condensing → release 40.65 kJ of energy per mole from surrounding Ex. Formation of cloud → surrounding warms  Climatograph Summary of average temperature and precipitation for each month in a given location – Horizontal axis → months of a year – Vertical axis on left → average precipitation (mm) – Vertical axis on right → average temperature (℃) Helps to identify factors that can affect the climate of an area  What makes them different? Latitude – Manokwari is closer to the equator → higher insolation – Insolation is the factor with the strongest effect on climate  What makes them different? Similar latitude → insolation similar Lerwick → surrounded by ocean and in the path of warm ocean current Whitehorse → inland  Practice What is the total average rainfall in summer (June, July, August)? What are the three months with the lowest average temperature?  Practice Prince Rupert, BC has similar latitude as Grande Prairie but is situated on the Pacific Coast. Compared to Grand Prairie, would you expect it to have – More/less seasonal temperature variations? – More/less precipitation?  Earth’s Biomes A large geographical region with – Particular range of temperature – Particular level of precipitation – Living organisms adapted to specific climate Biomes are open systems – Exchanges matter and energy with the surroundings Patterns of climates results in similar biomes distributed over Earth’s surface Earth’s Biomes Earth’s Biomes Tundra  Where? Just south of the frozen polar seas Isolation? Very little Precipitation? Less than 25 mm Climate? Winters are long and cold. Summers are short and cool. Plants and Animals? Lemmings, Caribou, Arctic hare, Arctic fox, Wolf. Taiga (Boreal Forest)  Where? Just south of the Tundra Isolation? Increased from Tundra Precipitation? 35- 100 cm/year Climate? Snowy winters with rapid melt in spring Plants and Animals? Coniferous trees, Moose, black bears, lynx, squirrels, wolves Deciduous Forest  Where? Found in both the Southren and Northeren hemisphere Isolation? Varied Precipitation? 75- 150 cm/year Climate? Four distinct seasons throughout the year Plants and Animals? Large diversity of animals and plants. Grassland  Where? Found in both the Southren and Northeren hemisphere. In almost every continent Isolation? Varied Precipitation? 25- 27 cm/year Climate? Has a prolonged dry season Plants and Animals? Grasses, stands of trees found near rivers and water sources. Ground squirels, pheasants, burrowing owls. Rain Forest  Where? Found along the equator Isolation? High Precipitation? Daily rain Climate? Temperature remain constant month to month Plants and Animals? Greatest biodiversity of all the Earth Biomes. Desert  Where? Found between 15 – 35 degrees latitude Isolation? High Precipitation? < 25 cm/year Climate? Dry, hot with infrequent rainfall Plants and Animals? Lizards, rattlesnakes, vultures, coyotes. Very little plant growth Canada’s Biomes Canada’s Biomes