Explain why one is essentially the same as the other. (2) 8. Determine the conjugate acid-base pairs in the following reactions: (Use 2 lines to connect the 2 pairs in each reaction.) (3) a. NH3(aq) + H2O(l) ↔ NH4+(aq) + OH-(aq) (base)NH3 and (acid)NH4+ OH- and H2O b. HNO2(aq) + H2O(l) ↔ H3O+(aq) + NO2-(aq) H2O and H3O+ NO2 and HNO2 c. HCN(aq) + H2O(l) ↔ H3O+(aq) + CN-(aq) CN and HCN H2O and H3O+ 9. How is the formula of a conjugate acid similar to its conjugate base, and how is it different?
3. Arrhenius model: A model of acids and bases; states that an acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution and a base is a substance that contains a hydroxide group and dissociates to produce a hydroxide ion in aqueous solution. 4. Bronsted-Lowry model: A model of acids and bases in which an acid is a hydrogen-ion donor and a base is a hydrogen ion acceptor. 5.
NH3 and CH3COOH Note: Conjugate acid-base pairs differ by one proton and a charge of 1 Amphoteric/Amphiprotic -a substance capable of reacting as an acid or a base -water in the above examples is amphoteric -another example is HCO3-1 which is part of the buffer system in our blood Polyprotic Acids -acids that have more than one ionisable hydrogen e.g. H2SO4 is an example of a diprotic acid Strong and Weak Acids and Bases -strong acids and bases complete react with water to release all of their hydrogen or hydroxide ions -weak acids and bases only partially ionize/dissociate and thus form equilibrium systems and have equilibrium constants associated with them -since
Main – group metals usually for one cation (positive ion). In a binary ionic compound the metal (cation) is named first. Then the nonmetal (anion) is named, and the suffix -ide is added. To create the formula, you switch the charges, and that tells you how many of each element you will need. For example: Cation Anion Formula Name of Compound Ba2+ I- Ba2+ I- Barium Ion Iodide Ion BaI2 Barium Iodide Type 2: Binary Ionic Type 2 Binary Ionic compounds consist of a metal and a nonmetal.
Water (H2O) is colorless liquid that’s the basis of life on Earth. It contains two hydrogen bonds and is a polar molecule; it has a dipole moment of 1.85D. Volume percent is a method used when preparing solution of liquids. It is defined as Concentration solute (v/v%) = [(volume of solute)/(volume of solution)] x 100%  This experiment is to use volume percent to create different concentration of 3M nitric acid solutions and investigate the effect of different concentration, which creates different strength of intermolecular forces, on the volume of a drop of nitric acid. Research question: What is the effect of different concentration of nitric acid on its volume of its drop?
This definition limits acids and bases to substances that can dissolve in water. Later on, Brønsted and Lowry defined an acid to be a proton donor and a base to be a proton acceptor. In this definition, even substances that are insoluble in water can be acids and bases. Whether or not an aqueous solution is neutral, acidic or basic depends on the hydrogen-ion concentration. We give the acidity of an aqueous solution in terms of the pH.
Given that silica is an absorbent, TLC is a “form of adsorption chromatography” (Varcoe 2001: 8-1). The silica gel used in the stationary phase is a highly polar compound capable of hydrogen bonding whereas in the mobile phase the solvent is a less polar compound, specifically ethyl acetate. | | Figure 1. Structure of silica gel particle (Varcoe 2001: 8-1) | Figure 2. Structure of Ethyl Acetate (Toxipedia 2010) | The polar interactions between the solutions and both of the absorbent and the solvent can occur as a dipole-dipole interaction, the result of the contact of two polar molecules with permanent dipoles such as hydrogen bonding and also dipole-induced dipole interaction in which a molecule with a permanent dipole polarizes another molecule.
July 29, 2011 Title: This report highlights an experiment involved with Acid-Base Titration. Introduction: According to the Arrhenius theory an acid can be defined as a substance that dissolves in water and produces hydrogen ions (H+), while a base produces hydroxide ions (OH-). The Bronsted-Lowry theory states that all acids are proton donors and all bases are proton acceptors. A neutralization reaction occurs when protons (H+) from an acid combine with hydroxide ions (OH-) from the base to produce salt and water. For instance, the neutralization of HCl by NaOH is written as: HCI + NaOH -----------> NaCl + HOH Equations for neutralization reaction are balanced so that the amount of H+ will be equal to the amount of OH-.
Alkanes composed of only carbon and hydrogen atoms are referred to as hydrocarbons. A hydrocarbon with the hydroxyl group is known as alcohol. The experiment was to determine and examine the structure of the alkanes and alcohols and the presence and relative strength of the two intermolecular forces. Intermolecular forces are the attractions that exist between atoms and molecules. The strength of the intermolecular forces of attraction determines whether a substance will be a solid, a liquid, or a gas.
Acid-base equilibria Define pH pH = -log10[H+] no units Define Ka with units For acid HA [H+][A-] Acid dissociation constant Ka = [HA] moldm-3 Temperature dependent, Ka varies with different bases Define Kw with units Ionic product of water Kw = [H3O+] [OH−] mol2dm-6 Temperature dependent, Define pKa pKa = −log10 Ka Define pKw pKw = −log10 Kw Understand the terms ‘strong’ and ‘weak’ as applied to acids and bases Difference between acid and acidic solution: • HCl acts as an acid when it dissolves in water and donates its proton to the water molecule • Solution is acidic because concentration of H3O+ ions is greater than conc of OH- ions Strong/weak acid – fully/partially ionised Strong/weak base – fully/partially dissociate Conc No of moles of acid dissolved in a given vol of water The greater the value of Ka the stronger the acid HA Strength of acid, measured by equil constant (which determines the POE) HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq) Equil lies so far to RHS that acid is considered to be completely ionised(strong acid) Recall the Brønsted-Lowry theory and use it to identify acids-bases Identify acid-base conjugate pairs and relate them by means of suitable equations Students are not expected to recall the Lewis theory of acids and bases Monoprotic/monobasic acid Acids that have a single proton to donate/accept Diprotic/dibasic acid Acids that have a two protons to donate/accept Acid Proton donor Base Proton acceptor Acid 1 Base 2 Acid 2 Base 1 H2SO4 + H2O H3O+ + HSO4- • Ionisation of H2SO4 in water occurs in 2 stages • HSO4- is conjugate base of H2SO4 but conjugate acid of SO42- Acid 3 Base 2 Acid 2 Base 3 HSO4- + H2O H3O+ + SO42- Calculate the pH of solutions of strong acids and strong bases and of weak acids given Ka