Nitroglycerine 100 g Nitro 1mol Nitro 227 g Nitro 29 mol gas 4mol Nitro = mol gas Or =.110 mol O 2 =.661 mol N 2 = 1.10 mol H 2 O = 1.32 mole CO 2

Nitroglycerine V = PV = nRT V = nRT/P mol ( L atm/mol K) 425 C 1atm 698 K V = 183 L

H 2 + Cl 2  2HCl(g) g of Cl 2 Limiting Reactant Problem – the hard way Moles HCl g of H 2 Moles Cl 2 Moles H 2 FW Balanced Eq Select limiting reagent Moles Cl 2 Moles H 2 used Final pressure = pressure of HCl + pressure of excess reagent Starting moles H 2 - Moles H 2 used Excess moles H 2 Moles HCl Moles H 2 xs Total moles of gas + PV = nRT P = 193 torr

H 2 + Cl 2  2HCl(g) g of Cl 2 Understanding Gases – the easy way Pressure Cl 2 Pressure H 2 g of H 2 Moles Cl 2 Moles H 2 FW PV = nRT Add to get Initial pressure Final pressure = Initial P = P Cl 2 + P H 2 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.

Stoichiometry ABCD + + Moles A Moles Cg of C FW Volume of C Molarity Molarity of C Volume Molecular weight # grams g of A FW Volume of A Molarity Molarity of A Volume Molecular weight Of A # grams Balanced Eq

Gases only!!!! Gas Stoichiometry ABCD + + Moles A Moles C g of A FW g of C FW Volume of A Molarity Volume of C Molarity Molarity of C Volume Molarity of A Volume Molecular weight # grams Molecular weight Of A # grams 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 H 2 at room temp? =

=

= 2.0g/mol 1kg _ 1000g = 1.92 x 10 3 m/s ≈ 2000 m/s ≈ 4300 mi/hr

Why does it take so long to smell gas that is released in the same room?

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

Gas Law Shortcuts All revolve around the fact that in gases, V and P does NOT depend on nature of gas. All revolve around the fact that in gases, V and P does NOT depend on nature of gas. Implications Implications Can sum moles of all products and then find P or V. (Dalton’s Law of Partial Pressures.) Can sum moles of all products and then find P or V. (Dalton’s Law of Partial Pressures.) 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 the volume of 1 mole of gas A at the same conditions. 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 the volume of 1 mole of gas A at the same conditions. Caution: Shortcuts are NOT always present. Caution: Shortcuts are NOT always present.

Polarity and IMF Polarity is the key to IMFs. Polarity is the key to IMFs. Select 2 molecules involved, find polarity of each. Select 2 molecules involved, find polarity of each. Polar/polar = dipole/dipole -strongest Polar/polar = dipole/dipole -strongest Nonpolar/nonpolar = induced/induced - strongest Nonpolar/nonpolar = induced/induced - strongest Polar / Nonpolar = dipole induced-dipole -strongest Polar / Nonpolar = dipole induced-dipole -strongest If dipole/dipole look for H-Bonding If dipole/dipole look for H-Bonding Requires: Requires:

Why don’t oil and water mix?