January 2013 Chemistry Regents #80-82

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Questions

Base your answers to questions 80 through 82 on the information below.

A student investigated heat transfer using a bottle of water. The student placed the bottle in a room at 20.5DC. The student measured the temperature of the water in the bottle at 7 a.m. and again at 3 p.m. The data from the investigation are shown in the table below.

80 Compare the average kinetic energy of the water molecules in the bottle at 7 a.m. to the average kinetic energy of the water molecules in the bottle at 3 p.m. [1]

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 The average kinetic energy of the water molecules at 7 a.m. is less than the average kinetic energy of the water molecules at 3 p.m. The average kinetic energy of the molecules is greater at 3 p.m.

81 State the direction of heat transfer between the surroundings and the water in the bottle from 7 a.m. to 3 p.m. [1]

HIGHLIGHT TO SEE THE ANSWER

 Heat was transferred from the surroundings to the water in the bottle. The water absorbed energy from the surroundings.

82 Show a numerical setup for calculating the change in the thermal energy of the water in the bottle from 7 a.m. to 3 p.m.[1]

HIGHLIGHT TO SEE THE ANSWER

 q = (800. g)(4.18 J/g•°C)(20.5°C - 12.5°C) (800)(4.18)(8)

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