# Chemistry calculations using formulas and STP to find values? Need help bc I don't understand the formulas.?

1. Determine the volume of a container that holds 2.4 mol of gas as STP.

2. What size container do you need to hold 0.0459 mol N2 gas at STP?

3. What volume will 1.02 mol of carbon monoxide gas occupy at STP?

4. If the pressure exerted by a gas at 25 degrees celsius in a volume of 0.044 L is 3.81 atm, how many moles of gas are present?

5. Dtermine the celsius temperature of 2.49 moles of gas contained in a 1.00-L vessel at a pressure of 143 kPa.

6. Calculate the volume that a 0.323-mol sample of a gas will occupy at 265 K and a pressure of 0.900 atm.

7. What is the pressure in atmospheres of a 0.108-mol sample of helium gas at a temperature of 20.0 degrees celsius if its volume is 0.505 L?

8. Determine the kelvin temperature required for 0.0470 mol of gas to fill a balloon to 1.20 L under 0.988 atm pressure.

9. Propane, C3H8, is a gas commonly used as a home fuel for cooking and heating.

a. calculate the volume that 0.540 mol of propane occupies at STP.

b. think about the size of this volume compared to the amount of propane that it contains. why do you think propane is usually liquified before it is transported?

10. Hydrogen gas at a temperature of 22.0 degrees celsius that is confined in a 5.00-L cylinder exerts a pressure of 4.20 atm. If the gas is released into a 10.0-L reaction vessel at a temperature of 33.6 degrees celsius, what will be the pressure inside the reaction vessel?

11. A sample of neon gas at a pressure of 1.08 atm fills a flask with a volume of 250 mL at a temperature of 24.0 degress celsius. If the gas is transferred to another flask at 37.2 degrees celsius at a pressure of 2.25 atm, what is the volume of the new flask?

12. What volume of beaker contains exactly 2.23x10 exponet -2 mol of nitrogen gas at STP?

Relevance
• Lexi R
Lv 7

STP = standard Temperature and pressure

This is T = 0 deg Celcius (273.15 K)

and P = 1.0 atm

At STP 1 mole of any ideal gas has a volume of 22.4 L. So keeping that in mind many of these questions can be done quite easily

1. Determine the volume of a container that holds 2.4 mol of gas as STP.

Since 1 mole has a volume of 22.4 L

Then Volume of 2.4 mol = 22.4 L/mol x 2.4 mol

= 53.76 L

= 54 L (2 sig figs)

2. What size container do you need to hold 0.0459 mol N2 gas at STP?

1 mol = 22.4 L

So 0.0459 mol occupies (22.4 L/mol x 0.0459 mol)

= 1.02816 L

= 1.03 L (3 sig figs)

Many of the rest of the questions need to use the gas equation

PV = nRT

P = Pressure

T = temp, must always be in Kelvin

V = volume

n = moles

R = constant. This is different for different units of P and V

you can look R up here

http://en.wikipedia.org/wiki/Gas_constant

4. If the pressure exerted by a gas at 25 degrees celsius in a volume of 0.044 L is 3.81 atm, how many moles of gas are present?

n = PV / RT

P = 3.81 atm

V = 0.044 L

T = 25 deg C = 298.15 K

R = 0.0821 L atm mol^-1 K^-1 (because P is in atm and V is in L)

n = (3.81 atm x 0.044 L) / (298.15 K x 0.0821 Latmmol^-1K^-1)

n = 0.00684857 mol

n = 0.0068 mol (2 sig figs)

5. Dtermine the celsius temperature of 2.49 moles of gas contained in a 1.00-L vessel at a pressure of 143 kPa.

Now, when you look up R you will see that there is no R value that fits for P = kPa and V = L. So you need to convert one of these values to a unit that fits. I would convert 143 kPa to atm, and then use R = L atm mol^-2 K^-1

Also remember the equation needs the temp in Kelvin, so you will have to convert to celcius at the end. deg C = Kelvin - 273,15

T = PV/nR

P = 143 kPa = 1.411 atm

http://www.unit-conversion.info/pressure.html

n = 2.49 mol

V = 1.00 L

R = 0.0821 L atm mol^-1 K^-1

T = 1.411 atm x 1.00 L / 2.49 mol x 0.0821 Latmmol^-1K^-1

T = 6.902 Kelvin

T = -266 deg C

7. What is the pressure in atmospheres of a 0.108-mol sample of helium gas at a temperature of 20.0 degrees celsius if its volume is 0.505 L?

P = nRT / V

V = 0.505 L

n = 0.108 mol

R = 0.0821 L atm mol^-1 K^-1

T = 20 deg C = 293.15 K

P = 0.108 mol x 0.0821 Latmmol^-1K^-1 x 293.15 K / 0.505 L

P = 5.15 atm

So, just manipulate the equation to get the right property out the front.

Make sure you are using the right units. And have a go at the rest of them.

• 5 years ago

RE:

Chemistry calculations using formulas and STP to find values? Need help bc I don&#39;t understand the formulas.?

1. Determine the volume of a container that holds 2.4 mol of gas as STP.

2. What size container do you need to hold 0.0459 mol N2 gas at STP?

3. What volume will 1.02 mol of carbon monoxide gas occupy at STP?

4. If the pressure exerted by a gas at 25 degrees celsius in a volume of 0.044 L...

Source(s): chemistry calculations formulas stp find values bc don 39 understand formulas: https://tr.im/qhchR
• 4 years ago

Stp Chem

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