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Clicker Question What is the smallest number of ice cubes at 0°C, each containing one mole of water, necessary to cool 500.0 g of liquid water initially at 20°C to 0°C at 1.00 atm? Assume for this problem that H and Cp are temperature independent. ΔHf° = -285.6 kJ/mol of H2O(l) ΔHf° = -291.6 kJ/mol of H2O(s) Cp = 75.3 J/molK for H2O(l) a) 1 b) 7 c) 14 d) 15 e) 126

OWL Question #1 In a coffee-cup calorimeter, 110.0 mL of 1.3 M  NaOH and 110.0 mL of 1.3 M  HCl are mixed. Both solutions were originally at 26.2°C. After the reaction, the final temperature is 34.9°C. Assuming that all the solutions have a density of 1.0g/cm3 and a specific heat capacity of 4.18 J/°C·g, calculate the enthalpy change for the neutralization of HCl by NaOH. Assume that no heat is lost to the surroundings or to the calorimeter.

Chapter 9: Problem #122

We know it should. But why? Determine q, w ΔE, ΔH for this process. Which helps us to explain why this happens?

Signs of values Ideal gas expanding into a vacuum: E a) + b) — c) 0 d) I am not sure about this.

Signs of values Ideal gas expanding into a vacuum: H a) + b) — c) 0 d) I am not sure about this.

Signs of values Ideal gas expanding into a vacuum: w a) + b) — c) 0 d) I am not sure about this.

Signs of values Ideal gas expanding into a vacuum: q a) + b) — c) 0 d) I am not sure about this.

Laws of Thermodynamics First Law The energy of the universe is constant. Second Law The entropy of the universe tends toward a maximum.

Laws of Thermodynamics First Law The quantity of energy is conserved. “You cannot win, you can only break even.” Second Law The quality of energy is not conserved. It’s usefulness decreases. “You cannot break even.”

Questions To Consider How can we predict which reactions are spontaneous (and what do we mean by spontaneous)? How can we provide support (mathematical and qualitative) for observations? Ice cream melts Coffee cools Why do systems reach equilibrium? That is, why doesn’t the ball go all the way down the hill?

Clicker Question Is the “pop bottle reaction” spontaneous or not spontaneous? a) Spontaneous b) Not spontaneous