Weight/Density Problem?

Question

I have this problem from homework that I'm having a hard time figuring out. I've looked in the book to try and solve it, but have had no luck.

Gasoline has a density of 0.86 g/ml. How much weight do you add to your care by filling the tank with 15 gallons of gasoline. Report in units of grams, kilograms, and pounds.

If anyone could assist me with solving the problem, I'd really appreciate it!

Answer 1

Density = mass / volume

You are given a density for gasoline and you are given a volume, from this you can calculate the mass.
mass = density * volume

Since your units of density are in g/mL and your volume is given in terms of gallons, you need to convert the volume into mL, or convert the density into g/gallon.
One you convert, it is simply a matter of plugging into the equation to find the mass (in terms of grams).

After you find the mass, just convert this number into the units you desire.
1000 g = 1 kg
2.2 pounds = 1 kg

To make your life easier here is unit converter,
http://www.digitaldutch.com/unitconverter/

*The question is poorly worded. The units it states you to report your answer in are units of mass, not weight.
Weight is a force with units of Newtons.
Weight is not the same thing as mass, this was a very poor choice of words on the part of your text book / teacher / whoever.

If you really wanted to find the weight of the gasoline, once you found its mass in kg, multiply by 9.81 m/s^2.
Weight = mass * gravity

Answer 2

First you need to get everything in consistent units.

Convert the 15 gallons to mL.

Multiply that by the density g/mL x mL = grams

convert grams to Kilograms and Kilograms to Lbs and you're done.

I don't know the conversion from gallons to mL directly but I'd bet it's in your textbook.

Answer 3

density = 0.86 g / ml.
Find out how many ml are in 15 gallons.
then multiply that by 0.86
Then do your unit conversions for kilograms and pounds

Answer 4

So, you need to convert gallons into milliliters to start with. Then mass = density*volume

Then you'll convert your answer, which is in grams, into kilograms, and then into pounds

Answer 5

You have to start with a coversion factor from gal to ml: there are 3785.4 ml per US gallon.

for 15 gal; Xg = 15*3785.4*.86 = 48831.66 g

In Kg, just divide by 1000: X = 48.83166 kg

For pounds, multiply the above by 2.2: ---> 107.43 lb

Answer 6

Try converting the gallons to litres, then multiply by the density.

Answer 7

Here's a hint - how many ml in 1 liter? How many liters in one gallon?

Answer 8

Gasoline weighs .86g/mL=.86kg/L
1 gal=3.785 L so 1 gal of gas weighs .86*3.785=3.2551kg=7.716#
15 gal weighs 107.64#
the weight increase is about 108#.