## Can anyone help me with these density problems!?

5) The least dense liquid known to the author is liquid hydrogen, which at its normal boiling point, 20 K, had a density of 0.071g/cm^3. Liquid helium also has a very low density, about .125g/cm^3 (at 4 K). Excluding these remarkable materials, make a list of liquids which at 1 atm can exist at densities of less than 0.5g/cm^3.

8) For some oil and gas drilling operations we need a high-density drilling fluid (called "drilling mud"). What is the density of a mud that is 50% wt. water, 50% wt. BaSO4 (barite), SG of barite = 4.49.

I know the answer is 102 lbm/ft^3, but I don’t know how to go about solving the problem

14) The American Petroleum Institute (API) gravity is defined in "degrees" by…

Deg API = (141.5 / specific gravity) – 131.5

Here the specific gravity is the ratio of the density of the liquid to that of water, both at 60 F.

What’s the relation between density in g/cubic cm and degrees API?

What advantages of this scale might have led the petroleum industry to invent and adopt it?

23) A cubic foot of water at a temp of 68 F (20 C) weighs 62.3 lbf on earth…

a) What is its density?

b) What does it weigh on the moon (g = 6ft/s^2)?

c) What is its density on the moon?

25) The slug and the poundal were invented to make the conversion factor (mass/length) / (force/time^2) have a coefficient of 1. A new unit of length or a new unit of time could just as logically have been invented for this. Let us name those units the "toof" and the "dnoces". What are the values of the toof and the dnoces in terms of the foot and the second.

I also know the answer to this is the toof = 32.2 ft, and the dnoces = s/sqrt 32.2, but I don’t know how to show this.

Help with any of these problems would be awesome! thanks a bunch! =]

April 27th, 2010 at 3:19 pm

8.

Density of water is 62.4 lb/ft^3 (inverse = 0.01602 ft^3/lb)

Density of barite is 4.49 * 62.4 = 280 lb/ft^3 (inverse = 0.003571 ft^3/lb)

Mix 100 lb of water with 100 lb of barite and you’ll have:

200 lb / (1.602 + 0.3571) ft^3 = 102 lb/ft^3

14) http://en.wikipedia.org/wiki/API_gravity

23)

a) 62.3 lb/ft^3 = 62.3 * 453.592 gm/lb * (1 ft^3 / 28316.8 cm^3) = 0.99795 gm/cm^3

b) g(earth) = 32.174 ft/s^2 g(moon) = 6 ft/s^2

62.3 * (6 / 32.174) = 11.618 lb/ft^3

c) 0.99795 * (6 / 32.174) = 0.18610 gm/cm^3