In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction.

A student heats 66.72 grams of nickel to 99.22 °C and then drops it into a cup containing 85.21 grams of water at 21.46 °C. She measures the final temperature to be 27.64 °C.

The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.74 J/°C.

Assuming that no heat is lost to the surroundings calculate the specific heat of nickel.

Specific Heat (Ni) = ___ J/g°C.

0.461 j/g·°C*

Explanation:

Heat absorbed by water

ΔT(Ni) = temperature change of metal = 99.22°C - 27.64°C = 71.58°C

ΔT(water) = temp change for water = 27.64°C - 21.46°C = 6.18°C

Heat flow into water = m(water)·c(water)·ΔT(water) = (85.24g)(4.184j/g·°C)(6.18°C) = 2204 joules = heat flow from metal (Ni)

Specific Heat of Ni

Q(Ni) = mass of Ni x specific heat of Ni x temp change of Ni

=> specific heat (based on data given) = Q(Ni)/(mass of Ni)(temp chg of Ni) = 2204j/(66.72g)(71.58°C) = 0461 j/g·°C*    

*(published value = 0.440 j/g·°C => %Error = (0.461 - 0.44)/(0.44) X 100% = 4.9%)

a electronegativity decreases beacuse the size of nucleus is bigger.

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