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Published byMargaretMargaret Spencer Modified over 9 years ago
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What is the formula for Gibbs Free energy? What does each variable represent? How can you tell if a reaction will be spontaneous? How can you tell if a reaction is exothermic or endothermic? What is entropy? Determine if the following reaction will be spontaneous/nonspontaneous, exo/endo, increase/decrease is entropy ΔH= -26700 J, T= 387, ΔS= -234
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1. Name one property of a solid, liquid, and gas. 2. Separate the phase changes into endothermic and exothermic processes. 3. How do you find the boiling point of a substance on a phase change diagram? 4. Draw a sketch of a phase change diagram and label the solid, liquid, and gas phases. 5. How do you know a state change is taking place on a freezing and boiling point graph? 6. How many moles of a gas are present at a pressure of 798 torr, a volume of 278 mL, and a temperature of 45 o C? 7. How many liters of NH 3 can be made from 5.6 g of H 2 ? 1. N 2 + 3H 2 2NH 3 8. What is the specific heat of a 4.3 g piece of metal that absorbs 1987 J of heat energy and the temperature changed from 16 o C to 54 o C 9. Using the Gibbs free energy equation, describe the following process: 1. ΔH= -25 KJ, T= 124 K, and ΔS= 5.o KJ/K
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Pg. 107
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Nature of reactants (how reactive they ARE) Concentration: Reaction speed increases when concentration of reactants increases Surface area: Increased surface area leads to increased reaction rate Temperature: Increased temperature allows for a greater chance of collision Catalysts: Causes a lower activation energy
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Most reactions do not go to completion. They are reversible Use a double arrow to show that an equation can be reversed Chemical equilibrium happens when the forward and backward reactions balance each other because they take place at equal rates As the concentration of reactants decrease, concentration of products increase
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The formation of NH 3. Used in fertilizers N 2 + 3H 2 2NH 3
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Can determine equilibrium constant- K eq Concentrations of the products raised to the power of their coefficients/ concentrations of the reactants raised to the power of their coefficients aA + bB cC + dD K eq = ([C] c [D] d )/ ([A] a [B] b ) K > 1: more products than reactants @ equil K < 1: more reactants than products @equil
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Write the expression for finding the equilibrium constant for the following reaction: N 2 + 3H 2 2NH 3 Find the equilibrium constant if the concentration of N 2 is 0.533 mol/L, H 2 is 1.600 mol/L, and NH 3 is 0.933 mol/L
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Says if a stress is applied to a system at equilibrium, the system shifts in the direction that relieves the stress Can predict how changes in temp, concentration, and volume (pressure) will effect equilibrium V and P related- if you increase the volume, you decrease the pressure Longer arrow shows which way equilibrium will shift ( or )
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An increase in the concentration of a reactant shifts the reaction toward the product Ex. CO +3H 2 CH 4 + H 2 O If products are removed, it will shift toward the products
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If you decrease the volume (increase pressure) reaction will shift to the side with the smaller amount of moles. Ex. CO +3H 2 CH 4 + H 2 O
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The reaction will shift in the opposite direction when the temperature is added Exothermic shift to left Endothermic shift to right
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