#1 - no way to know, without some information about the pressure.
#2,3 just remember that mass = density * volume
Look up the density of ice and aluminum, and you're almost done.
Same with these: How do you do them?
1.)What is the mass at 20 degrees Celsius of 5 liters of air?
2.)What is the volume in liters of a kilogram of ice at 0 degrees Celsius?
3.)What is the mass of a bar of aluminum measuring 1.0cm by 1.0cm by 10.0cm?
9 answers
Ice density: 0.9167 g/cm3 at 0 °C
Aluminum density: 2.7 g/mL
Aluminum density: 2.7 g/mL
number 1 requires the gas law in one way or another
at STP a mole of gas occupies 22.4 liters as a check
STP is 273 K we are at 293 K
I guess we are at one atm, it does not say
V = 5 liters
P = 1 atm
T = 293
R = 0.0821 liter·atm/mol·K
PV = n R T
n = PV/RT = 1 * 5 /(.0821*293)
n = .208 mol which seems about right
now what is the mass of a mol of air
say 80% N2 and 20% O2
.8*28 + .2*32 = 28.8 grams/mol
28.8 grams/mol * .208 mol = 6 grams
6 grams or .006 kilograms
at STP a mole of gas occupies 22.4 liters as a check
STP is 273 K we are at 293 K
I guess we are at one atm, it does not say
V = 5 liters
P = 1 atm
T = 293
R = 0.0821 liter·atm/mol·K
PV = n R T
n = PV/RT = 1 * 5 /(.0821*293)
n = .208 mol which seems about right
now what is the mass of a mol of air
say 80% N2 and 20% O2
.8*28 + .2*32 = 28.8 grams/mol
28.8 grams/mol * .208 mol = 6 grams
6 grams or .006 kilograms
Damon, that's not the math we are using. That is more advanced. Currently, we are using the equations between density, mass, and volume.
2.)What is the volume in liters of a kilogram of ice at 0 degrees Celsius?
given
0.9167 g/cm3 at 0 °C
which is
1.09 cm^2/g
(1.09 cm^3/g)(1 L/1000 cm^3)(1000 g/kg)
= 1.09 L/kg
by the way : "a pint is a pound the world around" :) (VERY approximate)
a pint is about half a liter
a pound is about half a kilogram
given
0.9167 g/cm3 at 0 °C
which is
1.09 cm^2/g
(1.09 cm^3/g)(1 L/1000 cm^3)(1000 g/kg)
= 1.09 L/kg
by the way : "a pint is a pound the world around" :) (VERY approximate)
a pint is about half a liter
a pound is about half a kilogram
Then they must give you the density of air
3.)What is the mass of a bar of aluminum measuring 1.0cm by 1.0cm by 10.0cm
Aluminum density: 2.7 g/mL
a ml is a cm^3 (nasty of whoever)
so
Al is 2.7 g/cm^2
you have 10 cm^3
so you have 27 grams
which is .027 kilograms
Aluminum density: 2.7 g/mL
a ml is a cm^3 (nasty of whoever)
so
Al is 2.7 g/cm^2
you have 10 cm^3
so you have 27 grams
which is .027 kilograms
That is why both Steve and I asked what the pressure was for the air in problem 1. The density of air or any gas depends strongly on Temp and pressure.
At STP conditions the density of air is very close to 1.29 g/cc.
That's 29/22.4 = ? with 29 being very close to the molar mass air at STP
That's 29/22.4 = ? with 29 being very close to the molar mass air at STP
1 answer