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Heat Review Game!. Rules: Every turn the white board and marker MUST be passed to the next team member. You may help your team members but only the person who’s turn it is may use the marker. You must show your work! (when appropriate)
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Heat Review Game! Rules: Every turn the white board and marker MUST be passed to the next team member. You may help your team members but only the person who’s turn it is may use the marker. You must show your work! (when appropriate) Every team should answer. The first team to answer correctly gets five points. The second gets four etc. If we get too loud or disrespectful we will stop and work on our review questions.
Define heat • Heat is the amount of energy in a substance.
Define Exothermic • Energy travels from the system to the surroundings.
50 g of steam is cooled from 140 °C to 80 °C. How much energy is released? • Hf= 80 cal/g • Hv= 540 cal/g • Csteam = 0.4 cal/g °C • Cliquid= 1.0 cal/g °C • Cice = 0.5 cal/g °C • q = m x C x ΔT • q = H x mol q = m x C x ΔT q = 50 g x .4 cal/g °C ( 100 -140 °C) q = - 800 cal q = H x m q = 540 cal/g x 50 g q = 27000 cal q =27000 + 800 q = -27800 cal
10 g of water is cooled from 95°C to 45°C? How much energy is released? • Hf= 80 cal/g • Hv= 540 cal/g • Csteam = 0.4 cal/g °C • Cliquid= 1.0 cal/g °C • Cice = 0.5 cal/g °C • q = m x C x ΔT • q = H x mol q = m x C x ΔT q = 10 g x 1.0 cal/g °C x (45 °C -95 °C) = -500 cal
What is represented by part 2? (be specific) Phase change between liquid and solid
What phase change occurs during condensation? • Gas to liquid
10 g of steam is heated from 105°C to 235°C? How much energy is needed? • Hf= 80 cal/g • Hv= 540 cal/g • Csteam = 0.4 cal/g °C • Cliquid= 1.0 cal/g °C • Cice = 0.5 cal/g °C • q = m x C x ΔT • q = H x m q = m x C x ΔT q = 10g x .4 cal/ g °C x (235 °C -105 °C) q = 728 cal
Sublimation occurs when: • A solid goes into the gas phase without going through the liquid phase.
Define temperature. • Temperature is a measure of the average kinetic energy of the molecules.
Ice is cooled from 0°C to -50°C. Is this process endothermic or exothermic? • Exothermic
While melting, matter goes from the ____ state to the _______ state. • Solid to the liquid
15 g of liquid water at 0 °C is frozen and then cooled to -25 °C. How much energy was released? • Hf = 80 cal/g • Hv= 540 cal/g • Csteam = 0.4 cal/g °C • Cliquid = 1.0 cal/g °C • Cice = 0.5 cal/g °C • q = m x C x ΔT • q = H x mol q = H x mol q = 15 g x 80 cal/g q = 1200 cal q = m x C x ΔT q = 15g x 0.5 cal/g °C x (-25 °C-0 °C) q = - 1875 cal q q = -1200cal + -1875 cal q = - 3075 cal
What is represented by part 4? Phase change between liquid and gas
Define specific heat. • Specific heat is the amount of energy need to raise the temperature of 1 gram of a substance 1 °C.
As a substance goes through section 2, what happens to the distance between the particles? • They spread apart.
What are the names of the processes happening during section 4? • Evaporation • Condensation
What are the names of the processes happening during section 2? • Melting • Freezing
20 g of ice is melted. How much energy is used? • Hf= 80 cal/g • Hv= 540 cal/g • Csteam = 0.4 cal/g °C • Cliquid= 1.0 cal/g °C • Cice = 0.5 cal/g °C • q = m x C x ΔT • q = H x m q = Hf x m q = 80 cal/g x 20 g q = 1600 cal
The temperature at which a substance in the liquid state freezes is the same as the temperature at which the substance_______. What is the name of this temperature? • Melts • Freezing point
In evaporation matter goes from the ____ state to the _____ state. • Liquid to the gas
Define Endothermic • Energy travels from the surroundings to the system.
What phase change occurs during freezing? • Liquid to solid