Iclicker-Unit-3

# Iclicker-Unit-3 - Lecture 23 Specific Heat Capacity c...

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1 Specific Heat Capacity, c ChemQuiz Heat the same mass of water and ethanol on the same hot plate. Compared with the water, the temperature of the ethanol reaches 50°C: A. faster B. slower C. at the same time Quantity of energy needed to increase the temperature of 1 g of a substance by 1°C. water ethanol c (water) = 1 cal/g-°C c (ethanol) = 0.57 cal/g-°C Lecture 23 ChemQuiz Ethanol cools to 0°C faster because A. Heat transfers from ethanol faster. B. Heat transfers from water faster. C. Less heat needs to be removed from ethanol per degree temperature change. D. More heat is removed from the ethanol per degree temperature change. water ethanol crushed ice Lecture 23 ChemQuestion You place 10.0 g of copper at 600°C into 100 mL of water 0°C . What is the final temperature of the water (approximately)? c (copper) = 0.39 J/g-K c (water) = 4.2 J/g-K A. 5°C B. 50°C C. 500°C D. 325°C Lecture 23 ChemQuestion Which of the Which of the following will following will react with react with Fe 2 O 3 to produce molten molten Fe Fe ? A. C (s) B. Sn (s) C. Fe (s) D. Al (s) 2 Al (s) + 3/2 O 2 (g) Al 2 O 3 (s) H 1 = +824 kJ/mol o Fe 2 O 3 (s) 2 Fe (s) + 3/2 O 2 (g) H 1 = 1676 kJ/mol o H 3 o 2 Al (s) + Fe 2 O 3 (s) Al 2 O 3 (s) + 2 Fe = ( +824 ) + ( 1676 ) kJ/mol = 852 kJ/mol ! (l) Note: D is the “best” answer, but you can also consider Sn; 3 moles of Sn are needed to balance a reaction with 2 moles of Fe 2 O 3 . Using Hess’ Law, you can calculate that this reaction is also exothermic (but only by 86 kJ, probably not enough to get molten iron) Lecture 24 Lecture 25 ChemQuiz A. The heat released per gram for octane is greater. B. The heat released per gram of hydrogen is greater. C. The heat released per mole of octane is greater D. The heat released per mole of hydorgen is greater. E. Both B and C are correct Which statement best describes comb for octane, C 8 H 18 , and hydrogen, H 2 ?

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Iclicker-Unit-3 - Lecture 23 Specific Heat Capacity c...

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