How Do You Calculate the Coefficient of Expansion for Glass Using Mercury?

[cukitas2001]

Hey guys, having some trouble on some thermodynamics this time.

1) A glass flask whose volume is V_o at 0.0 degrees C is completely filled with mercury at this temperature. When flask and mercury are warmed to a temperature of T, a volume V of mercury overflow.

If the coefficient of volume expansion of mercury is B_merc, compute the coefficient of volume expansion of the glass.

I tried relating the two expansions with the formulas:
deltaV=B*V_o*deltaT and V=V_o(1+B*deltaT)

I tried to assume they both had the same V_o and tried subing an expression i got from the mercury expansion into my expression for glass expansion but i keep having V cancel out and its required int he final answer. Anyone know where I am going wrong or have any ideas?

 

[Doc Al]

Write two equations: one for the volume of mercury in terms of V_o, B_merc, and T; the other for the volume of the flask in terms of V_o, B_glass, and T. Then use those two expressions to write an equation that says: The difference between the two volumes at temperature T equals V.

 

[cukitas2001]

Write two equations: one for the volume of mercury in terms of V_o, B_merc, and T; the other for the volume of the flask in terms of V_o, B_glass, and T. Then use those two expressions to write an equation that says: The difference between the two volumes at temperature T equals V.

ok thanks man it was the difference thing i didnt know i was trying substitution for soem reason...thanks truckloads again