Question

The density of mercury metal `13.6` `g`/`cm^3`. How many lbs would a `5.0` `L` container of mercury weigh?

Answer 1

That's a lot of mass, 68 kg, 150 odd pounds? Quite probably it exceeds your own mass.

Explanation:

There are `0.454*lb*(kg^-1)` so `2.203*kg*(lb^-1)`, and `1*cm^3 = 1*mL`

So we just do the conversion:

`5.0*cancel(L)xx1000*cancel(cm^3)cancel(L^-1)xx13.6*g*cancel(cm^-3)` `=` `??g`;

; `??cancel(g)xx10^(-3)cancel(kg)*cancel(g^-1)xx(2.203)lb*cancel(kg^-1)`

`=` `??` `lb`

Answer 2

`"5.0 L Hg"` weighs `"150 lb Hg"`.

Explanation:

First convert liters to cubic centimeters since the density is given in `"g/cm"^3"`. Use `""5.0xx10^3 "cm"^3"` to represent two significant figures using scientific notation.

`5.0cancel"L"xx(1000"mL")/(1cancel"L")xx(1"cm"^3)/(1cancel"mL")=5.0xx10^3 "cm"^3 "Hg"`

Next use the density and given volume to determine the grams of Hg.

`5.0xx10^3cancel("cm"^3 "Hg")xx(13.6"g Hg")/(1cancel("cm"^3 "Hg"))="68000 g Hg"`

Convert mass in grams to weight in pounds.

`"1 lb=453.592 g"`

`68000cancel"g Hg"xx(1"lb Hg")/(453.592cancel"g Hg")="150 lb Hg"`