NitroglycerineNitroglycerine4C3H5N3O9(l) 12CO2(g) + 10H2O(g) + 6N2(g) + O2(g)

100 g Nitro1mol Nitro227 g Nitro

29 mol gas4mol Nitro

= 3.193 mol gas

Or = .110 mol O2

= .661 mol N2

= 1.10 mol H2O= 1.32 mole CO2

NitroglycerineNitroglycerine4C3H5N3O9(l) 12CO2(g) + 10H2O(g) + 6N2(g) + O2(g)

V =

PV = nRT V = nRT/P

3.193 mol(0.082057 L atm/mol K)425 C

1atm

698 K

V = 183 L

HH22 + Cl + Cl22 2HCl(g) 2HCl(g)

g of Cl2

Limiting Reactant Problem – the hard way

Moles HCl

Moles HClg of H2

Moles Cl2

Moles H2

FW

FW

Balanced Eq

Balanced Eq Select limiting

reagent

Moles Cl2 Moles H2 used

Final pressure = pressure of HCl + pressure of excess reagent

Starting moles H2

- Moles H2 used

Excess moles H2

Moles HCl Moles H2 xs Total moles of gas+PV = nRT

P = 193 torr

HH22 + Cl + Cl22 2HCl(g) 2HCl(g)

g of Cl2

Understanding Gases – the easy way

Pressure Cl2

Pressure H2g of H2

Moles Cl2

Moles H2

FW

FW

PV = nRT

PV = nRTAdd to get

Initial pressure

Final pressure = Initial P = P Cl2 + P H2

Remember that the composition of a gas does NOT effect the pressure it exerts. So, since there is no change in the number of MOLES of gas during the reaction, there will be no change in the pressure. Thus the initial pressure equals the final pressure.

StoichiometryStoichiometryA B C D+ +

Moles A Moles C

g of C

FW

Volume of C

Molarity

Molarity of CVolume

Molecular weight

# grams

g of AFW

Volume of A

Molarity

Molarity of AVolume

Molecular weightOf A

# grams

Balanced Eq

Gases only!!!!

GasGas Stoichiometry StoichiometryA B C D+ +

Moles A Moles C

g of A FW g of CFW

Volume of A

Molarity

Volume of C

Molarity

Molarity of CVolume

Molarity of AVolume

Molecular weight

# grams

Molecular weightOf A

# grams

Balanced Eq

Balanced Eq

(T and P/V same)

Volume of A

Pressure of A

PV = nRT

Pressure of C

Volume of C

PV = nRT

What is RMS for HWhat is RMS for H22 at room at room temp?temp?

Μ

RTu

32 )298)(/3145.8(3 KKmolJ

=

What is RMS for HWhat is RMS for H22 at room at room temp?temp?

Μ

RTu

32 )298)(/3145.8(3 KKmolJ

=

What is RMS for HWhat is RMS for H22 at room at room temp?temp?

Μ

RTu

32 )298)(/3145.8(3 KKmolJ

=2.0g/mol

1kg _1000g

= 1.92 x 103 m/s≈ 2000 m/s≈ 4300 mi/hr

Why does it take so long Why does it take so long to smell gas that is to smell gas that is

released in the same released in the same room?room?

Problems involving GasesProblems involving Gases

PV=nRT can be used to get moles of PV=nRT can be used to get moles of gas from P, V and T. Once you have gas from P, V and T. Once you have mole then it is just a normal limiting mole then it is just a normal limiting reagent or stoichiometry or titration reagent or stoichiometry or titration or ….or ….

Gas Law ShortcutsGas Law Shortcuts All revolve around the fact that in gases, V All revolve around the fact that in gases, V

and P does NOT depend on nature of gas.and P does NOT depend on nature of gas. ImplicationsImplications

Can sum moles of all products and then find P Can sum moles of all products and then find P or V. (Dalton’s Law of Partial Pressures.)or V. (Dalton’s Law of Partial Pressures.)

Ratio of n:V or n:P is constant (at a given temp Ratio of n:V or n:P is constant (at a given temp and P or V) So 2 moles of gas C takes up twice and P or V) So 2 moles of gas C takes up twice the volume of 1 mole of gas A at the same the volume of 1 mole of gas A at the same conditions.conditions.

Caution: Shortcuts are NOT always Caution: Shortcuts are NOT always present.present.

Polarity and IMFPolarity and IMF

Polarity is the key to IMFs.Polarity is the key to IMFs. Select 2 molecules involved, find Select 2 molecules involved, find

polarity of each.polarity of each. Polar/polar = dipole/dipole -strongestPolar/polar = dipole/dipole -strongest Nonpolar/nonpolar = induced/induced - Nonpolar/nonpolar = induced/induced -

strongeststrongest Polar / Nonpolar = dipole induced-dipole -Polar / Nonpolar = dipole induced-dipole -

strongeststrongest If dipole/dipole look for H-BondingIf dipole/dipole look for H-Bonding

Requires:Requires:

O H

(F,N)

+-

N

(F,O)

-

Why don’t oil and Why don’t oil and water mix?water mix?