nlingraham
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*Messed up title, should have been find initial temp of copper*
8.00 g of aluminum at 200 °C and 18.0 g of copper are dropped into 50.0 cm3 of ethyl alcohol at 15 °C. The temperature quickly comes to 26.0 °C. What was the initial temperature of the copper?
Density of ethyl alcohol = .789 g/ml
mass of ethyl alcohol = 39.45 g, .03495 kg
mass of copper = .018 kg
mass of aluminum = .008 kg
Tf = 299 K
Ti, alum = 473 K
Ti, eth = 288 K
c for aluminum = 900 J/kg*k
c for ethyl alcohol = 2400 J/kg*k
c for copper = 385 J/kg*k
Qa + Qc + Qe = macaΔT + meceΔT + mcccΔT = 0
=(.008)(900)(-174) + (.03945)(2400)(11) + (.018)(385)(299-Ti) = 0
Ti = 268.51 K or -4.5 °C
That's what I did, but it says not quite and tells to check for rounding errors. However, I didn't round anything until the very end, so I'm not quite sure where I went wrong. I also tried -4.494 but that was wrong too.
Homework Statement
8.00 g of aluminum at 200 °C and 18.0 g of copper are dropped into 50.0 cm3 of ethyl alcohol at 15 °C. The temperature quickly comes to 26.0 °C. What was the initial temperature of the copper?
Density of ethyl alcohol = .789 g/ml
mass of ethyl alcohol = 39.45 g, .03495 kg
mass of copper = .018 kg
mass of aluminum = .008 kg
Tf = 299 K
Ti, alum = 473 K
Ti, eth = 288 K
c for aluminum = 900 J/kg*k
c for ethyl alcohol = 2400 J/kg*k
c for copper = 385 J/kg*k
Homework Equations
Qa + Qc + Qe = macaΔT + meceΔT + mcccΔT = 0
The Attempt at a Solution
Qa + Qc + Qe = macaΔT + meceΔT + mcccΔT = 0=(.008)(900)(-174) + (.03945)(2400)(11) + (.018)(385)(299-Ti) = 0
Ti = 268.51 K or -4.5 °C
That's what I did, but it says not quite and tells to check for rounding errors. However, I didn't round anything until the very end, so I'm not quite sure where I went wrong. I also tried -4.494 but that was wrong too.