IB Chem Unit 3: Acids and Bases

What are some properties of acids? 

aqueous solutions of acids conduct electricity, tastes sour, causes litmus to turn red and phenolphthalein to turn colorless, neutralize bases to form salt and water

What are the products of a reaction between an acid and an active metal?

hydrogen gas and a salt

What are the products of a reaction between carbonates or hydrocarbonates and acids?

salt, carbon dioxide, and water

What is hydrochloric acid?

HCl

What is hydrofluoric acid? 

HF 

What is hydrobromic acid?

HBr

What is hydroiodoic acid?

HI

What is nitric acid? 

HNO3

What is acetic//ethanoic acid?

HC2H3O2

What is sulfuric acid?

H2SO4

What is sulfurous acid? 

H2SO3 

What is phosphoric acid?

H3PO4

What are arrenhius acids?

substances that when dissolved in water increase the concentration of H+ ions

What are the strong acids? 

HCl, HI, HBr, HNO3, H2SO4, HClO3, HClO4

What are the general properties of bases?

aqueous solutions of bases conduct electricity, taste bitter, feel slippery, cause litmus to turn blue and phenophtalein to turn pink, neutralize acids to form salt and water

What is an arrenhius base?

substance that when dissolved in water increases the concentration of OH- ions

What are strong bases?

substances that dissociate fully in water and thus their solutions are excellent conductors of electricity 

What are the strong bases?

LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

What is a Bronsted-Lowry acid?

a substance that can donate a proton to another substance

What is a Bronsted Lowry base? 

a substance that can accept a proton from another substance

What are conjugate acid-base pairs?

according to the Bronsted-Lowry definition, an acid and base must both be present, the reaction between an acid and a base always yields their conjugate bases and acids

What is the conjugate of a strong acid?

a weak base

What is the conjugate of a weak acid?

a strong base

What is amphoterism? 

the property of a substance to act either as an acid or a base depending on the reaction conditions 

What are some examples of amphoteric substances?

H2O, HCO3-, HSO4-

In a neutral solution (such as pure water), the concentrations of the hydrogen ion and hydroxide ion are equal. Thus, 

Kw = [1.0 x 10-7] [1.0 x 10-7] = 1.0 x 10-14

What is the concentration of OHin a 0.1 mol dm-3 HCl solution?

What is the concentration of OHin a solution with a [H+] =2.0 x 10-6 mol dm-3 ?

How can you calculate pH?

pH is the -log(H+ concentration)

How can you calculate pOH?

-log(OH concentration) or 14 + log (H+ concentration)

How do you calculate the pH of a weak acid? 

you need to find the hydrogen ion concentration at equilibrium, this requires an equilibrium expression which you use to solve for the H+ concentration and then use that to do the -log equation

The greater the Ka, the _____ the acid

the greater the Ka, the stronger the acid 

What is another way to express acid strength?

pKA which is -logKa

What is the relationship between acidity, pKa, pH, and Ka?

as acidity increases, pH and pKa decrease but Ka increases

What are polyprotic acids? 

have more than one acidic proton, if the difference between Ka for first dissociation and subsequent Ka values is 10³ or more, the pH generally depends only on the first dissociation 

What is the relationship between pKa and pKb?

pKa+pKb = 14 at 25 celsius

How can we calculate Ka from pH?

write the equilibrium reaction, use the pH to determine H+ concentration, set up equilibrium table, plug in equilibrium concentrations into the Ka expression

What is a lewis acid? 

an electron pair acceptor

What is a lewis base? 

an electron pair donor 

Why is rain naturally acidic and what is the equation to represent this?

because of carbon dioxide that dissolves into the rain water and reacts to form carbonic acid

CO2 (g) + H2O (l) ←→ HsCO3 (aq) and then H2CO3 (aq) ←→ HCO3- (aq) + H+(aq)

What does the pH of rain need to be for it to be considered acid rain?

less than 5

What are the two main chemicals that cause acid rain fro our atmosphere? 

NOx and Sox