Chemistry Practice Problems Calorimetry Practice Problems Solution: A hot lump of 106.2 g of an unknown substance init...

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# Solution: A hot lump of 106.2 g of an unknown substance initially at 153.2°C is placed in 35.0 mL of water initially at 25.0°C and allowed to reach thermal equilibrium. The final temperature of the system is 53.2°C. What is the identity of the unknown substance? Assume no heat is lost to the surroundings.

###### Problem

A hot lump of 106.2 g of an unknown substance initially at 153.2°C is placed in 35.0 mL of water initially at 25.0°C and allowed to reach thermal equilibrium. The final temperature of the system is 53.2°C. What is the identity of the unknown substance? Assume no heat is lost to the surroundings.

###### Solution

We’re being asked to determine the identity of the unknown substance in the given system.

Recall that heat (q) can be calculated using the following equation:

$\overline{){\mathbf{q}}{\mathbf{=}}{\mathbf{mc}}{\mathbf{∆}}{\mathbf{T}}}$

q = heat, J

+qabsorbs heat
–qloses heat

m = mass (g)
c = specific heat capacity = J/(g·°C)
ΔT = Tf – Ti = (°C)

Based on the given system:

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