Question #16856

2 Answers
Apr 14, 2017

3.61

Explanation:

its quite simple if you go by a simple method of finding density at STP
we got
"Density"=("Mass")/("Volume")
we know that mas of HBr is 81 units
and one mole of HBr weighs 81 gm
and we also know that the volume of one mole of any gas is 22.4 Lhence , we have got our data .
upon substitution with the formal equation of density we get .
d=81/22.4=3.61g m^(-3)

Apr 14, 2017

The density of "HBr" at STP is 3.563 g/L.

Explanation:

Yes, there is a gas law equation for density.

It is a variation of the Ideal Gas Law.

color(blue)(|bar(ul(color(white)(a/a)pV = nRTcolor(white)(a/a)|)))" "

Since

n = "mass"/"molar mass" = m/M,

we can write

pV = m/MRT

or

p = (m/V)(RT)/M

And density ρ = m/V,

so

p = ρ(RT)/M

This gives

ρ = (pM)/(RT)

STP is defined as 1 bar and 0 °C.

In this problem,

p color(white)(ll)= "1 bar"
M = "80.91 g·mol"^"-1"
Rcolor(white)(l) = "0.083 14 bar·L·K"^"-1""mol"^"-1"
T color(white)(l)= "273.15 K"

ρ = (1 color(red)(cancel(color(black)("bar"))) × 80.91 "g"·color(red)(cancel(color(black)("mol"^"-1"))))/("0.083 14" color(red)(cancel(color(black)("bar")))·"L"·color(red)(cancel(color(black)("K"^"-1""mol"^"-1"))) × 273.15 color(red)(cancel(color(black)("K")))) = "3.563 g/L"