Question #d36b2

1 Answer
Feb 22, 2017

Answer:

#"15.2 mL"#

Explanation:

As you know, the density of a substance tells you the mass of exactly one unit of volume of that substance.

In your case, liquid bromine is said to have a density of #"3.102 g mL"^(-1)#, which means that every #"1 mL"# of bromine has a mass of #"3.102 g"#.

#color(blue)(color(purple)("3.102 g") color(white)(.)"mL"^(-1)) -> color(purple)("3.102 g")color(white)(.) color(black)("for every") color(white)(.)color(blue)("1 mL")color(white)(.)"of liquid Br"_2#

Now, your goal here is to figure out the volume of liquid bromine that would contain #0.295# moles of bromine. In order to be able to do that, you must convert the number of moles of bromine to grams.

Bromine has a molar mass of #"159.808 g mol"^(-1)#, which means that every #1# mole of bromine has a mass of #"159.808 g"#.

In your case, the sample of liquid bromine will have a mass of

#0.295 color(red)(cancel(color(black)("moles Br"_2))) * "159.808 g"/(1color(red)(cancel(color(black)("moles Br"_2)))) = "47.14 g"#

You can now use the density of liquid bromine as a conversion factor to determine exactly how many milliliters of bromine would have a mass of #"47.14g"#

#47.14 color(red)(cancel(color(black)("g"))) * color(blue)("1 mL")/(color(purple)(3.102)color(red)(cancel(color(black)("g")))) = color(darkgreen)(ul(color(black)("15.2 mL")))#

The answer is rounded to three sig figs, the number of significant figures you have for the number of moles of bromine present in the sample.