Net Ionic Equations

HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)

What really happens:

H+(aq) + OH-(aq) H2O(l)

Sodium ion and chloride ion are “spectator ions”

Reactions involving weak bases

HCl(aq) + NH3(aq) NH4+(aq) + Cl-(aq)

Net-Ionic Equation:

What are the products: CH3CO2H(aq) + NaOH(aq)

1. CH3CO2H2+(aq) + NaO(aq)

2. CH3CO2-(aq) + H2O(l) + Na+(aq)

3. CH4(g) + CO2(g) + H2O(l)

Net-Ionic Equation:

What are the products: HCN(aq) + NH3(aq)

1. NH4+(aq) + CN-(aq)

2. H2CN+(aq) + NH2-(aq)

3. C2N2(s) + 3 H2(g)

Net-ionic equation:

Solution Concentration: Molarity

• Molarity = moles solute per liter of solution

• 0.30 mol NH3 dissolved in 0.500 LConcentration =

Written like: [NH3] = 0.60 M

• If you dissolve 0.32 mol NH3 to make 750 mL of solution, what is [NH3]?

pH: Quantitative Measure of Acidity

Acidity is related to concentration of H+ (or H3O+)

pH = -log[H+] [H+] = 10-pH

pH ScaleIn pure water, a few molecules

ionize to form H3O+ and OH–

H2O + H2O OH– + H3O+

In acidic and basic solutions, these concentrations are not equalacidic: [H3O+] > [OH–]basic: [OH–] > [H3O+]neutral: [H3O+] = [OH–]

pH ScaleMeasure how much H3O+ is in a

solution using pH pH < 7.0 = acidic pH > 7.0 = basic pH = 7.0 = neutral

Measure of H3O+ and OH– concentration (moles per liter) in a solution

As acidity increases, pH ?

pH ScaleThe pH scale is logarithmic:The pH scale is logarithmic:

100100 101022 log(10log(1022) = 2) = 21010 101011 log(10log(1011) = 1) = 111 101000 log(10log(1000) = 0) = 00.10.1 1010–1–1 log(10log(10–1–1) = –1) = –10.010.01 1010–2–2 log(10log(10–2–2) = –2) = –2

pH = –log [HpH = –log [H++]]

pH ScalepH = –log [HpH = –log [H33OO++]]

What is the What is the pH if [HpH if [H++] = 1 x 10] = 1 x 10–5–5? Acidic or ? Acidic or basic?basic?

What is the What is the pH if [HpH if [H++] = 1 x 10] = 1 x 10–9–9? Acidic or ? Acidic or basic?basic?

What is the pH if [HWhat is the pH if [H++] = 0.000057 M?] = 0.000057 M?

pH of Strong Acid Solutions

For monoprotic strong acids: [H+] = [acid]

What is the pH of a 2.4 x 10-2 M solution of HNO3?

Finding [H[H33OO++] from pH] from pH

[H[H++] = 10] = 10-pH-pH

What is [HWhat is [H++] if pH = 8.9?] if pH = 8.9?

What is the possible range of pH values?