Chemistry Help?

Question

The stated capacity of a railroad tank car designed to carry liquified petroleum gas (LPG) is 280,000 gallons of water. If the densities of water and LPG are 1.00 g/mL and 0.537 g/mL respectively, how many pounds of LPG can the car carry?


Provide the correct answer in scientific notation with the correct number of sig figs. You must use the following conversion factors: 1 L = 1000 mL; 1 L = 1.057 quarts; 1 gallon = 4 quarts; 1 g = 0.03527 oz; 1 lb = 16 oz

Answer 1

Ron B's way of doing it with the shortcut works, but in case the teacher wants the full work:

Step 1: Convert gallons of water to mL

280,000 x 4 quarts/gallon x 1L/1.057 quarts x 1000ml/L =
1, 059, 602, 649.0066 mL

-You use the conversion factors to cancel all the units you don't want in your answer

Step 2: Convert mL to grams of LPG with the density, then from grams to pounds

NOTE: the teacher tries to trick you by giving you the density of water, which you don't need. mL is a volume, and is the same for any substance..the only difference in that volume of water and that volume of LPG is the weight

1, 059, 602, 649.0066 mL x 0.537g/mL x 0.03527 oz/gram x 1lb./16 oz. = 1, 254, 303.9735 lbs.

BF
4th yr Chem Major
U of O (Canada)

Answer 2

Yo can use your conversion factors, but here is an easy short cut from my days as a chem engineer.

Water has 8.34 lbs. / gallon. Multiply that by the density of LPG and you will have how many lbs /gal it weighs. Now multiply that answer by the 280,000 gallons and you have your answer.

Answer 3

0.537g/L is also expressed as the LPG Specific Gravity as 0.537. (S.G. has no units as it's a figure relative to the density of water.(which is 1.000)...i.e. Relative Density).

1 US gallon of water = 8.3 lbs.
280,000 gallons = 280,000 x 8.3lb/gal = 2,324,000 lbs.
= 2,324,000 lbs x 0.537 = 1,247,988 lbs of LPG.

1 UK gallon of water = 10 lbs.
280,000 gallons x 10 lb/gal = 2,800,000 lbs.
2,800,000 x 0.537 = 1,503,600 lbs LPG

Answer 4

1.2543 x 10*6 lb