at what average would heat have to be removed from 1.5L of a) water and b) mercury to reduce the liquid's temperature from room temperature to its freezing point in 3 minutes?

Question

mrnood · Answer

You need to look up a few things first:

Density of Water
Density of Mercury

Specific Heat Capacity of Water
Specific Heat Capacity of Mercury

Freezing point of Water
Freezing point of Mercury.

also make an statement of what you will use as 'Room Temperature'

Post those here, and I'll help you solve what to do with them.

anonymous · Answer

okayyy,,,wait,,i will post here

anonymous · Answer

Density of Water 1000kg/m3
 Density of Mercury 13534 kg/m3
 Specific Heat Capacity of Water 1
Specific Heat Capacity of Mercury 0.033
Freezing point of Water 0 degrees C
Freezing point of Mercury. -38.83 degrees C
 'Room Temperature' 20 degrees C

mrnood · Answer

OK


So - you have 1.5 l of water and 1.5 l of Hg (Mercury)
Calculate the mass of each of those.

Also calculate the change in temperature for each fluid

anonymous · Answer

15000grams of water and 1500 grams of mercury

anonymous · Answer

what will i use in change in temperature in both?

mrnood · Answer

That's correct for water - but Hg is much more dense....

Also - what are the units for specific heat capacity you have posted?

It will be easier if you find them in J/gK  (or J/g degC)

mrnood · Answer

Change in temperature is (Room temperature - freezing point)

anonymous · Answer

specific heAT IS cal/gram C

mrnood · Answer

So
Find the mass of the mercury (you know its volume and density)
Find how many calories = 1 Joule

anonymous · Answer

1 cal is 4.184 joules

mrnood · Answer

good
density = mass/vol
Find the mass of the mercury

anonymous · Answer

1 joule is .2389

anonymous · Answer

mercury,what it its volume?

mrnood · Answer

The question tells you - you have
a) 1.5 l of water and 
b) 1.5 l of Mercury

anonymous · Answer

volume= gram?

mrnood · Answer

no - you need to know the mass (grams) - 
and you already know density = 13534 kg/m3
and Volume = 1.5l
(You may need to know that 1m^3 = 1000 l)

from the above you need to work out 
mass of 1.5l of mercury

mrnood · Answer

Let's stick with the water for now OK?

What is the mass of 1.5l of water   (your answer above was not quite correct I'm afraid)

anonymous · Answer

mass = density * V = 13600(1.5) = 9066.67, then?

anonymous · Answer

mass of water = 1000(1.5) = 666.67

mrnood · Answer

You have 'divided' not multiplied in the above answers - the equation is right but the answer is wrong.

Nearly there...

anonymous · Answer

why divide....? $$\rho= m/V$$

anonymous · Answer

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