• MatterMatter is anything that has mass and occupies space.• It exist in 3 phases: Solid – fixed shape and volume. Liquid – fixed volume & not rigid in shape (shape of thecontainer). Gas – neither fixed volume nor a rigid shape (depend onthe volume and shape of the container)• Matter can be classified into two categories: Pure substance – fixed composition and unique set ofproperties. Mixtures – composed two or more substances.
Elements• A type of matter that cannot be broken down into 2 ormore pure substance.• consists of only one kind of atoms. All atoms of a givenelement are identical, having the same size, mass andchemical properties.• The atoms of one element are different from the atomsof all other elements – each elements is unique.• Example: Copper (Cu) – use in electrical wiring, jewelry, waterpipe. Aluminium (Al) – household utensils
Compound• Pure substance that composed of two or moredifferent elements that are chemically boundtogether. Example: Water contain oxygen (O) and hydrogen (H).• Compounds have fixed compositions – always containthe same elements in the same percentages by mass. Water contain precisely 11.19% hydrogen and 88.81%oxygen.• The properties of compounds are different from thosethe elements they contain. Example: salt (sodiumchloride).
Mixtures• Contain two or more substances combined in such away that each substance retains its chemical identity. Copper sulfate do not react with sand when itcombine/shake together.• There are two types of mixtures:a.a. HomogeneousHomogeneous – or uniform mixtures which thecomposition is the same throughout. Also called assolution (contain solvent and solute).b.b. HeterogeneousHeterogeneous – or nonuniform mixtures which thecomposition varies throughout. Most rocks fall into thiscategories.
To learn about matter, you must also familiar with:• AtomsAtoms - which are composed of electrons, protonsand neutrons.• MoleculesMolecules - the building blocks of several element andmany compounds. Molecular substances can beidentified by their formulae or their names.• IonsIons - species of opposite charge found in all ioniccompounds. Using relatively simple principles, it ispossible to derive the formulae and names of ioniccompounds.
Postulates of the Dalton’s Atomic TheoryPostulates of the Dalton’s Atomic Theory1. All matter consists of atomsatoms.2. Atoms of one element cannotcannot be converted into atomsof another element.3. Atoms of an element are identicalidentical in mass and otherproperties and are different from atoms of any otherelement.4.4. CompoundsCompounds result from the chemical combination of aspecific ratio of atoms of different elements.
Some featuresof Dalton’satomic theorySome featuresof Dalton’satomic theory
Structure of the AtomStructure of the Atom• An atomatom is an electrically neutral, spherical entitycomposed of a positively charged central nucleussurrounded by one or more negatively charged electrons.• An atomic nucleus consists of protons and neutrons(except H). Proton (p+) has a positive charge Neutron (n0) has no charge Electron (e-) has a negative charge• An atom is neutralneutral because the number of protonsin nucleus is equals the number of electronssurrounding the nucleus.
ElectronsElectrons• Are common to all atoms, carry a unit negative charge (-1) and have a very small mass, roughly 1/2000 that of thelightest atom.• Every atom contains a definite number of electrons. Hydrogen contain 1 electron Uranium contain 92 electrons• Electrons are found in theouter regions of the atom,where they form whatamounts to a cloud ofnegative charge.
Protons and Neutrons; the atomic nucleusProtons and Neutrons; the atomic nucleus• Proton, which has a mass nearly equal to that of anordinary hydrogen atom.• The proton carries a unit positive charge (+1), equal inmagnitude to that of the electron (-1).• The neutron is an uncharges particle with a mass slightlygreater than that of a proton.• Because proton and neutrons are much heavier thanelectrons, most of the mass of an atom (>99.9%) isconcentrated in the nucleus, even though the volume ofthe nucleus is much smaller than that of the atom.
Atomic Number, Mass Number and Atomic SymbolAtomic Number, Mass Number and Atomic Symbol• Atomic number (Z)-Atomic number (Z)- number of protons in nucleus ofeach of its atoms.• Example: C atoms (Z=6) have 6 protons• Mass number (A)Mass number (A) – the total number of proton andneutrons in the nucleus of an atom.• The nuclear mass number and charge are often writtenwith the atomic symbolatomic symbol. Atomic symbol – element symbol based on its English, Latinor Greek name. Atomic number (Z) is written as a left subscript Mass number (A) – is written as left superscript
Isotopes and Atomic Masses of the ElementsIsotopes and Atomic Masses of the Elements• IsotopesIsotopes – all atoms of an element are identical in atomicnumber but not in mass number (different numbers ofneutrons).• Example: Carbon (Z=6)Carbon (Z=6) – have 6 protons and 6 neutrons. A small % have 7 neutron (A=13) and 8 neutron (A=14). Carbon have three isotopes – 1212C,C, 1313C andC and 1414CC• The chemical properties of an element are primarilydetermine by the no of electron.• So, all isotopes of an element have nearly identicalchemical behavior (even though have different masses).H11 H21 H31 Cl3517 Cl3717
6 protons, 8 (14 - 6) neutrons, 6 electrons6 protons, 5 (11 - 6) neutrons, 6 electronsHow many protons, neutrons, and electrons are in C146 ?How many protons, neutrons, and electrons are in C116 ?
13 protons, 14 (27 - 13) neutrons, 10 (13 – 3) electrons16 protons, 16 (32 - 16) neutrons, 18 (16-2) electronsHow many protons, neutrons, and electrons are in Al2713?3+How many protons, neutrons, and electrons are in S3216?2-
Atomic Masses; the Carbon-12 ScaleAtomic Masses; the Carbon-12 Scale• Individual atoms are far too small to be weighed on a balance.Individual atoms are far too small to be weighed on a balance.• Atomic massAtomic mass is the mass of an atom in atomic mass units(amu).• The atomic mass of an element indicates how heavy, on theaverage, one atom of that element is compared with an atomof another element.• To set up a scale of atomic mass, it is needed a standard valuefor one particular species.• One atomic mass unitatomic mass unit is defined as a mass exactly equal toone-twelfth the mass of one carbon-12 atom.
On this scale1H = 1.008 amu16O = 16.00 amu1 amu = 1/12 x mass of one C-12 atomIn the periodic table, atomic masses arelisted directly below the symbol of theelementIn the periodic table, atomic masses arelisted directly below the symbol of theelement
Relative Atomic Mass,Relative Atomic Mass, AArr ; Relative Molecule Mass,; Relative Molecule Mass, MMrr• Some definitions of atomic and molecular masses:Some definitions of atomic and molecular masses:• If the mass ratio of one atom of an element to one atom ofIf the mass ratio of one atom of an element to one atom ofcarbon-12 is known, the relative atomic mass of the element cancarbon-12 is known, the relative atomic mass of the element canbe calculated.be calculated.Relative atomic mass,Relative atomic mass, AArr of an =of an =element Xelement XMass of one atom of XMass of one atom of X1/12 x mass of one1/12 x mass of one 1212C atomC atomRelative molecular mass,Relative molecular mass, MMrr of a =of a =compound Wcompound WMass of one molecule of WMass of one molecule of W1/12 x mass of one1/12 x mass of one 1212C atomC atom
The mass ratio of one atom of nitrogen to one atom ofcarbon-12 is 1.24899. What is the relative mass ofnitrogen?Start from the definition of relative atomic mass of an element= 12 x 1.24899= 1.24899Mass of one atom of Nmass of one atom of carbon-12Relative atomic mass of N = Mass of one atom of N1/12 x mass of one 12C atom= 14.98788
• The amount of each isotope of an element expressed inpercentage is called the relative abundancethe relative abundance or isotopicabundance of that element.• The total relative abundance is 100%.• Element that have more than one isotope – measure theaverage mass for all occurring mixture of isotopes.• If an element has n isotopes, the average atomic mass of theelements is:Fraction abundance, f =Percentage of isotope100
• Example: Lithium(7.42 x 6.015) + (92.58 x 7.016)100= 6.941 amu
Tentukan jisim atom relatif, Ar bagi unsur Neon yangdiketahui mempunyai tiga isotop iaitu 20Ne, 21Ne dan 22Nedengan peratus kelimpahan masing-masing 90. 92%, 0.26%dan 8.82%.= 20.1890.92100+Ar Ne = ( )x 20 ( )x 210.26100( )x 228.82100+
• Relative masses of individual atoms can be determined using amass spectrometer.• The substance to be analysed must first be vapourised togaseous atoms or molecules in the vapourisation chambervapourisation chamber.• The spectrometer is connected to a vacuum pumpvacuum pump so that theair molecules will not interfere with incoming particles.• Gaseous atoms or molecules are ionised in the ionisationionisationchamberchamber as a result of bombardment by the beam of highenergy electrons emitted by an electron gunelectron gun. When atom loses electron, positive ion are produced. Example: C+ion is formed when an electron is removed from acarbon atom.
• In the acceleration chamberacceleration chamber, the cation formed are acceleratedby a potential difference of 500 to 2000V toward a magneticmagneticfield.field.• The magnetic field deflects the ions from their straight-linepath (depends on the mass to charge ratio of the ions). Thepath of more massive ions curve less than the less massive ions(species can be separate).• All ions will be directed to thedetectordetector plate where theyproduce a weak signal or current.• Mass spectrumMass spectrum showing peaks ofvarious heights at certainmass/charge (m/e) values.
Mass spectrum ofchlorineChlorine contains only twoisotopes: 34.97 amu (75.53%) and36.97 amu (24.47%)Average atomic mass ClAverage atomic mass Cl= (34.97 x 75.53) + (36.97 x 24.47)100 100= 35.46 amu
Names and Formulas ofNames and Formulas of Ionic CompoundsIonic Compounds• Many ionic compound are binary compoundbinary compound orcompound formed from just two element Metal (cation)– many metal names end in –ium–ium Nonmetal (anion) – adds the suffix –ide–ide in the end ofnonmetal name
• Ternary compoundTernary compound – compounds consisting of threeelements Anion groups containing different elements also used ––ideide Example: Lithium hydroxide (LiOH) Potassium cyanide (KCN)Names and Formulas ofNames and Formulas of Ionic CompoundsIonic Compounds
Names and Formulas ofNames and Formulas of Ionic CompoundsIonic Compounds• Compound with metal that can form more than one ionCompound with metal that can form more than one ion Metal in transition element (B groups) Example: Iron can form FeFe2+2+and FeFe3+3+ion. When iron react with chlorine, FeClFeCl22 (iron(II)chloride)and FeClFeCl33 (iron (III)chloride). Common names for the ion with the lower charge – ous– ous for the ion with the higher charge – ic– ic
• Families of Oxoanions -Families of Oxoanions - Usually nonmetal, is bonded toone or more oxygen atoms. The ion more O atoms takes the nonmetal root, -ate-ate The ion fewer O atoms takes the nonmetal root, -ite-iteNames and Formulas ofNames and Formulas of Ionic CompoundsIonic CompoundsClO4-is perchlorate ionClO3-is chlorateClO2-is chloriteClO-is hypochloriteClO4-is perchlorate ionClO3-is chlorateClO2-is chloriteClO-is hypochlorite• If have four oxoanions in the family:
• Compound composed of nonmetallic elements.• Many molecular compound are binary compound.• Similar to naming binary ionic compounds.• Adds the suffix –ide–ide in the end of second element.• Example:Names and Formulas ofNames and Formulas of Molecular CompoundsMolecular Compounds
HI hydrogen iodideNF3 nitrogen trifluorideSO2 sulfur dioxideN2Cl4 dinitrogen tetrachlorideNO2 nitrogen dioxideN2O dinitrogen monoxideTOXIC!Laughing Gas
• To avoid confusing in naming thecompound, Greek prefixes has beenused to denote the number of atomsof each element present.Names and Formulas ofNames and Formulas of Molecular CompoundsMolecular Compounds
• AcidAcid – a substance that yields hydrogen ion (H+) whendissolved in water.• Two common types of acid: Binary acidBinary acid solution form when certain gaseous compoundsdissolved in water. OxoacidOxoacid – similar to oxoanions except Suffix – ate– ate becomes – ic– ic in the acid Suffix – ite– ite becomes – ous– ous in the acidNames and Formulas ofNames and Formulas of Acids and BasesAcids and Bases
• BaseBase – a substance that yields hydroxide ion (OH-) whendissolved in water.Names and Formulas ofNames and Formulas of Acids and BasesAcids and Bases
• The molemole (mol) is the amount of a substance that contains thesame number of particles (atoms, molecules or ions) that existsin exactly 12.00 grams of 12C.• The definition specifies the number of objects in a fixed mass ofsubstance.• A mole represents 6.022 x 1023particles, whatever they may be.Therefore, 1 mole of substance = fixed number of chemicalentities and has a fixed mass.
Molar massMolar mass is the mass of 1 mole of in gramsionsAtomsMolecules1 mole 12C atoms = 6.022 x 1023atoms = 12.00 g1 12C atom = 12.00 amu1 mole 12C atoms = 12.00 g 12C1 mole lithium atoms = 6.941 g of Li
Mass (g)Mass (g) = no. of moles x no of grams1 molNo. of molesNo. of moles = mass (g) x 1 molno. of grams• Convert between amount (mol) and mass (g), use molarmass ( M in g/mol)No. of entitiesNo. of entities = no. of moles x 6.022 x 1023entitiesno. of gramsNo. of molesNo. of moles = no. of entities x 1 mol6.022 x 1023entities• Convert between amount (mol) and no. of entities, useAvogadro’s number (6.022 x 1023entities)(1)(1)(2)(2)(3)(3)(4)(4)
• Convert between number of entities and mass, firstconvert to number of moles.No. of atomsNo. of atoms = mass (g) x 1 mol x 6.022 x 1023entitiesno. of grams 1 mol(5)(5)
Berapakah bilangan atom H yang terdapat di dalam 1 molgas NH3?1 mol NH3 mengandungi 3 mol atom HBilangan atom H dalam 1 mol NH3= 3 x 6.023 x 1023= 1.807 x 1024atomHitung bilangan ion Ca2+dan ion Cl-dalam 1 mol CaCl21 mol CaCl2 mengandungi 1 mol ion Ca2+dan 2 mol ion Cl-= 2 x 6.023 x 1023= 1.205 x 1024atomBilangan ion Ca2+=6.023 x 1023Bilangan ion Cl-
Acetylsalicylic acid, C9H8O4, is the active ingredient of aspirin.a.What is the mass in grams of 0.509 mol of Acetylsalicylicacid?b.How many moles of C9H8O4 are in 1 g sample of aspirin thatcontains 91.6% by mass of C9H8O4?= [9(12.01) + 8(1.008) + 4(16.00)] g/mol = 180.15 g/molThe molar mass of C9H8O4a. 0.509 mol x 180.15 g = 91.7g1 mola. 1.000 g x 0.916 x 1 mol = 5.08 x 10-3mol180.15 g
The relationships between mass (m in grams) of an element andnumber of moles of an element (n) and between number ofmoles of an element and number of atoms (N) of an element.M= molar mass in g/molNA = Avogadro’s number
Do You Understand Molar Mass?How many atoms are in 0.551 g of potassium (K) ?1 mol K = 39.10 g K1 mol K = 6.022 x 1023atoms K0.551 g K1 mol K39.10 g Kx x6.022 x 1023atoms K1 mol K= 8.49 x 1021atoms K