Answer:
50. 54,915 J
51. 27.0 g
Step-by-step explanation:
The dimensional analysis tells you how to compute these. Multiplying specific heat, J/(g·°C), by the product of mass and temperature change will give you energy.
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50. (375 g)((70 -45) °C)(4.184 J/(g·°C)) = 54,915 J
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51. M((50 -25)°C)(4.184 J/(g·°C)) = 2825 J
M = 2825/104.6 g ≈ 27.0 g