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Question:

A 20.0 g sample of aluminum is cooled 7.5 CThe specific heat capacity of Al is 0.900 J/gCWhat is the energy change for this sample?

A) 140 kJB) 140 JC) -140 kJD) -140 JE) This question cannot be answered unless the amount of water is known.Is the answer B? I keep getting -135 J for some reason

Answer:

7.5c (.900J/gC)(20g) everything cancels but J using Unit Cancellation 135J Rounding for sigfigs (2 for 7.5c) 140J, answer B
Well, you could always make meatballs to go with the spaghettiOr for the burgers you could saute some onions, bell peppers and or mushrooms to top them off, or put a little cube of blue cheese in the center of the burger before you cook itToast the buns with a little garlic butter.
Cook boneless skinless chicken breasts in a large skillet with a little oil about 4 minutes per side on medium heatAdd one chopped onion, cook briefly and add 1 cup of chicken brothCook about 3 minutes then add one jar of pasta sauceTurn heat to low, cover and let simmer until chicken is done, approximately 20 minutesMeanwhile, cook some pasta following directions on the boxDrain the pasta and serve the chicken and sauce over the pastaServe with a bagged salad and Italian bread.
Well, you could always make meatballs to go with the spaghettiOr for the burgers you could saute some onions, bell peppers and or mushrooms to top them off, or put a little cube of blue cheese in the center of the burger before you cook itToast the buns with a little garlic butter.
Cook boneless skinless chicken breasts in a large skillet with a little oil about 4 minutes per side on medium heatAdd one chopped onion, cook briefly and add 1 cup of chicken brothCook about 3 minutes then add one jar of pasta sauceTurn heat to low, cover and let simmer until chicken is done, approximately 20 minutesMeanwhile, cook some pasta following directions on the boxDrain the pasta and serve the chicken and sauce over the pastaServe with a bagged salad and Italian bread.
7.5c (.900J/gC)(20g) everything cancels but J using Unit Cancellation 135J Rounding for sigfigs (2 for 7.5c) 140J, answer B

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