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1. A U-tube contains liquid of unknown density. An oil of density 785 kg/m3 is poured into one arm of the tube until the oil column is 15 cm high. The oil-air interface is then 7 cm above the liquid level in the other arm of the U-tube. Find the density of the liquid.

I know that P1=P2

I said P1 = Patm + (density of oil)(g)(.15m) + (density of unknown)(g)(.07m)

P2 + Patm + (density of unknown)(g)(.15)

When I solved for the density, I got and answer of 1471.875.

Is this right? I get the feeling I did something wrong. Please help!

2. A well-insulated styrofoam bucket contains 143 g of ice at 0oC. If 21 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system?(cwater=4186 J/kg.oC, Lf=33.5x104 J/kg, Lv=22.6x105 J/kg)

Qlost= steam

Qgain = ice

qlost=q gain

(1) M ice * C ice * (Teq-0) + M ice * Lf + M ice * C water * (Teq - 0)

(2) M steam * C steam * (Teq - 100) + M steam * Lv + M steam C water ( 100 - 0)

I equated the two equations, and then solved for Teq. I messed up somewhere, I think with temeperatures. Any help will be appreciated.