# Cunife 1 The Special Alloy

Chemistry Level 5

Cunife 1 is an alloy used in making wires in light bulbs and thermionic valves. It composes of copper, nickel and iron. A $$10.00\text{ g}$$ sample of Cunife 1 was immersed in an $$\ce{HCl}$$ bath, and $$854.94 \text{ mL}$$ of hydrogen gas was collected under $$2\text{ atm}$$ and $$298.15 \text{ K}$$. However, one metal in the alloy was purely unoxidized. Another $$10.00\text{ g}$$ sample of Cunife 1 at $$100^\circ C$$ was then dumped in a calorimeter containing $$50.00\text{ g}$$ water at $$10.00^\circ C$$ and at thermal equilibrium the temperature of the metal-water mixture was measured at $$11.738^\circ C$$ by the calorimeter’s thermistor. What is the percent composition (by mass) of copper in Cunife 1?

Hint: One of the metals cannot be oxidized by $$\ce{HCl}$$.

Details and Assumptions:

• Universal Gas Constant $$R = 0.08206 \text{L atm/(mol K)}$$.

• Specific heat in $$\text{J/(g K)}$$: $$\ce{Cu}$$ – 0.39, $$\ce{Ni}$$ – 0.44, $$\ce{Fe}$$ – 0.45, $$\ce{H2O}$$ – 4.184

• Molar mass in $$\text{g/mol}$$: $$\ce{Cu}$$ – 63.55, $$\ce{Ni}$$ – 58.69, $$\ce{Fe}$$ – 55.85.

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