Bagrut Chemistry study guide
Bagrut Chemistry · Work through your exam, one topic at a time.
The Bagrut in Chemistry is the Israeli matriculation (Bagrut) examination in chemistry, taken by high-school students who choose chemistry as an elective subject and by external candidates completing matriculation requirements. It is a written, Hebrew-language examination built around the standard Israeli chemistry curriculum: atomic structure and the periodic table, bonding and intermolecular forces, the mole and stoichiometry, states of matter, equilibrium, acids and bases including buffers, thermochemistry, electrochemistry, kinetics, and organic chemistry. The Bagrut Chemistry study guide has 10 sections and about 3,366 words.
01Structure of the Atom and the Periodic Table
Atomic structure questions ask you to move between three representations: the electron configuration, the element's position in the periodic table, and physical trends such as atomic radius, first ionization energy, electronegativity and electron affinity. You are usually given a proton number and asked to explain a trend, not just state it.
378 words, about 2 min02Chemical Bonding and Intermolecular Forces
Ionic bonding: electron transfer between a metal with low ionization energy and a nonmetal with high electron affinity; the lattice is held by electrostatic attraction, giving high melting points, brittleness, and conductivity only when molten or aqueous. Covalent bonding: shared electron pairs, with bond order and bond energy rising from single to triple.
353 words, about 2 min03Stoichiometry and the Mole Concept
n = m / M, where M is the molar mass in g/mol. One mole contains 6.02x10^23 particles, and one mole of any ideal gas occupies 22.4 L at STP (0 °C, 1 atm) or about 24.5 L at 25 °C, 1 atm.
323 words, about 2 min04Gases, Liquids, Solids and Phase Changes
Ideal gas equation: PV = nRT with R = 0.0821 L atm mol-1 K-1 (or 8.314 J mol-1 K-1). Temperature must be in kelvin.
328 words, about 2 min05Chemical Equilibrium and Le Chatelier's Principle
A reversible reaction reaches equilibrium when the forward and reverse rates are equal and concentrations stop changing, although both reactions continue. For aA + bB <= cC + dD, Kc = [C]^c[D]^d / ([A]^a[B]^b), with pure solids and pure liquids omitted because their concentration is constant.
348 words, about 2 min06Acids, Bases, Salts and Buffer Solutions
Brønsted-Lowry: an acid donates a proton, a base accepts one. Strong acids (HCl, HBr, HI, HNO3, H2SO4, HClO4) ionize completely; weak acids ionize partially and are described by Ka.
351 words, about 2 min07Thermochemistry and Energetics
ΔH is negative for exothermic reactions (energy released, products lower in enthalpy) and positive for endothermic ones. Calorimetry uses q = mcΔT, where m is the mass of the solution, c is its specific heat capacity (4.18 J g-1 K-1 for water) and ΔT is the temperature change.
327 words, about 2 min08Oxidation-Reduction and Electrochemistry
Oxidation is loss of electrons (oxidation number rises); reduction is gain. Rules: elements are 0; O is usually -2 (except in peroxides, -1); H is +1 with nonmetals; a monatomic ion equals its charge; the sum equals the overall charge.
297 words, about 1 min09Reaction Kinetics and Reaction Mechanisms
Rate = k[A]^m[B]^n, where m and n are experimental orders, not the coefficients. Orders are found from initial-rate data: if doubling [A] doubles the rate, the order in A is first; if it quadruples, second; if nothing happens, zero.
354 words, about 2 min10Organic Chemistry: Functional Groups, Isomerism and Reaction Pathways
Identify the group first: it determines the suffix, the polarity, the intermolecular forces and the reactions. Alkane: unreactive except for radical substitution with halogens under UV.
307 words, about 2 min