Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mass, Volume and Specific Gravity

  1. Oct 21, 2012 #1
    I am trying to solve a question which gives me the volume of a mixture and its specific gravity and the percentage of one of the substances in that mixture by mass(everything else in the mixture is irrelevant). I need to find the mass of that substance but I can't seem to understand what I am doing. From what I understand, to get the amount of the substance in the mixture by mass I need the mass of the solution. I looked up this formula on the internet
    volume = mass/specific gravity
    using this I can find the mass of the mixture which I can use to find the mass of the substance. according to the above formula
    mass = volume * specific gravity
    volume is in gallons and S.G is unitless. this gives me a mass in gallons. At this point I am totally lost since I can't find the mass in mass units unless I have the density. I have never worked with specific gravity before so I don't really know too much about it aside from the fact that its a ratio of densities which doesn't really help me much. So how would I find the mass with the information I'm given?
     
  2. jcsd
  3. Oct 22, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    welcome to pf!

    hi wahaj! welcome to pf! :smile:
    the missing information is that specific gravity is always relative to water (unless the question specifies otherwise) …

    so you only need to know the density of water :wink:
     
  4. Oct 22, 2012 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Specifically, the specific gravity of a substance is its density divided by the density of water.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Mass, Volume and Specific Gravity
  1. Mass? or volume? (Replies: 2)

Loading...