# Chemistry

A sample of argon gas at STP occupies 56.2 liters. Find the number of moles of argon and the mass in the sample

1. 10
1. 1 mol occupies 22.4 L at STP. Solve for n, then n = grams/molar mass. You know molar mass and n, solve for grams.
OR you may use PV = nRT to solve for n.

posted by DrBob222
2. PV = nRT

n = PV/RT @ STP T= 0+273k; P = 1atm R = 0.821 L- atm/mol-K

n = 1atm(56.2L)/0.821 L- atm/mol-K(273k)
n = 2.50 mole
2.50 moles of Ar =39.984g of Ar/1mole of Ar

posted by tabs
3. Solution:

1) Rearrange PV = nRT to this:

n = PV / RT
2) Substitute:

n = [ (1.00 atm) (56.2 L) ] / [ (0.08206 L atm mol¯1 K¯1) (273.0 K) ]
n = 2.50866 mol (I'll keep a few guard digits)

3) Multiply the moles by the atomic weight of Ar to get the grams:

2.50866 mol times 39.948 g/mol = 100. g (to three sig figs)

posted by Al

## Similar Questions

1. ### Chemistry

I am really confused on this problem pleas help me. N2H4(l)+O2(g)(arrow)N2(g)+2H2O(g) a. How many liters of N2 (at STP) form when 1.0 kg N2H4 react with 1.0 kg O2? b. How many grams of excess reagent remain after the reaction? 1
2. ### chem

Show work 1. How many moles of oxygen will occupy a volume of 2.50 liters at 121.6 kPa and 331 K? 2. An unknown volume of chlorine gas (Cl2) is resting at 127 °C at a of pressure 152.4 kPa. If the gas weighs 191.4 g, what is the
3. ### chemistry

What volume (in liters) does 3 g sample of Argon (Ar) gas occupy at standard conditions (STP)?
4. ### Chemistry

A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this?
5. ### chemistry

sample of argon gas collected at a pressure of 1.11 atm and a temperature of 28.0 oC is found to occupy a volume of 20.3 liters. How many moles of Ar gas are in the sample?
6. ### Chemistry

An unknown amount of gas occupies 30.0 L at 2.1 ATM and 298K. How many moles does the sample contain? What is the mass if the gas is helium? What is the mass if the gas is argon?
7. ### Chemistry

An unknown amount of gas occupies 30.0 L at 2.1 atm and 298K. How many moles does the sample contain? What is the mass if the gas is helium? What is the mass if the gas is argon?
8. ### Chemistry

An unknown amount of gas occupies 30.0 L at 2.1 atm and 298K. How many moles does the sample contain? What is the mass if the gas is helium? What is the mass if the gas is argon?
9. ### chem

A sample of hydrogen gas occupies 16.8 L at STP. How many moles of the gas are present? Answer in units of mol
10. ### Chemistry

Determine the molar mass of each of the following gases? A. 2.90 g of gas that occupies 0.500 L at 0 C and 1.00 atm (STP) B. 1.48 G of gas that occupies 2.00 L at 0 C and 760 mmHg (STP) C. 0.726g of a gas that occupies 855 mL at

More Similar Questions