 So this is a two-party example. It says acetone has a density of 0.7857 grams per cubic centimeter So that density is also a conversion factor So we always have to remember that whenever we have one of those types of units that's a combined unit We can use it as a conversion factor for the first so for the first question What's the mass of 17.56 mills of acetone? So what you're really can doing is just converting from volume to mass So you have volume units there in milliliters and you have mass units in grams So you just cancel out your Units to get the units that you want you need the other conversion factor one mill equals one cubic centimeter So that's what I use first to cancel out my mills of cubic centimeters Then I can use the density and multiply that cancelling out the cubic centimeters giving me the Appropriate answer so we have to get that answer into the right number of sig figs and I think a lot of these answers are checking to see if you realize that that your rounding rules and Your significant zero so you got around that number that you get from the calculator up to 13.80 And since there's four Sig figs in the given you got to put that zero in there and remember your units too So it's 13.80 grams and then the second question What is the volume of seven point two two grams of acetone a little easier you only need to use Excuse me the density as The conversion factor, but you're flipping it over this time to get volume and I stopped at cubic centimeters just to Show you that cubic centimeters is also a volume unit so you can use that as well so I just canceled out my grams to get my cubic centimeters and Again, this is three significant digits you got to round up from what the Calculator gives you so nine point one nine cubic centimeters. Let me know if there are any issues with this one