QUESTION 1 Some nutrition labels give energy content in kJ i

QUESTION 1 Some nutrition labels give energy content in kJ (instead of Calories). How many Calories are in a 1046kJ bagel? Note: this question is asking about nutritional calories (Cal). where: 4184 J 1000 cal 1 Cal. QUESTION 2 Which of the following is not a statement of the First Law of Thermodynamics? The total energy of the universe is constant. E surroundings O Heat naturally flows from hot objects to cold objects QUESTION 3 Which of the following is not a state function? The straight-line distance between New York City and Los Angeles. O How many miles a person (chosen at random) drives to get from New York City to Los Angeles. O The elevation of Mt Everest. O The intenal energy of a gas. QUESTION 4 How much work must you do to accelerate a 1.0 kg billiard ball from rest to 3.0 m/s? (answer in Joules)

Solution

1) 1 calorie = 4.184 kilojoules ; 1 kilojoule = 0.239 calories

1046kJ = 1046 X 0.239 = 249.94 calories= 250 calories

2) First law of thermodynamics state all the first three options except option 4 i.e heat generally flow from hot objects to cold objects. (this is the statement from second law of thermodynamics).

3) The straight line distance between New York city and Los Angeles is not the state function.

4) Mass of billiard ball = 1 kg

velocity = 3.0 m/sec

work to accelerate the ball (kinetic energy) = 1/2 mv² = 1/2 x (1x3²) = 4.9 Joules