# How would you calculate the volume of 3.03 g of H2(g) at a pressure of 560 torr and temp of 139 k?

##### 1 Answer

#### Explanation:

I would use the ideal gas law equation

#color(blue)(PV = nRT)#

and rearrange to solve for the volume of the gas,

#V = (nRT)/P" "# , where

*universal gas constant*, usually given in as

Now, you have everything you need to calculate the volume of the gas *except* the number of moles.

To find how many moles of gas you have in that sample, use hydrogen's molar mass

#3.03color(red)(cancel(color(black)("g"))) * "1 mole H"_2/(1.00794color(red)(cancel(color(black)("g")))) = "3.006 moles H"_2#

Now plug in your values and solve for *torr* to *atm*

#V = (3.006color(red)(cancel(color(black)("moles"))) * 0.082(color(red)(cancel(color(black)("atm"))) * "L")/(color(red)(cancel(color(black)("mol"))) * color(red)(cancel(color(black)("K")))) * 139color(red)(cancel(color(black)("K"))))/(560/760color(red)(cancel(color(black)("atm")))) = color(green)("47 L")#

The answer is rounded to two sig figs, the number of sig figs you gave for the pressure of the gas.