Sophia Struzziero Exam 1 Review Supplementary MaterialsChem 111 Qin 02/22/2022Spring 2022Exam1:Chapter 1Scientific Notation● If the exponential is negative, then the notation given is for a number less than 1● If the exponential is positive, then the notation given is for a number more than 1N X 10xSignificant Figures1. All non-zero digits and zeros between non-zeroes are significant.2. Zeroes at the beginning are not significant.3. At the end zeroes are significant if there is a decimal point and they are not significant if there is no decimal point.Adding and Subtracting● When adding or subtracting, the final answer is given the same number of decimal places as the number with the fewestdecimal placesMultiplication and Division● When multiplying or dividing, the final answer is given the same number of sig figs as the value with the fewest sigfigs.Precision vs. Accuracy● If measurements are very close to each other in value after repeated tries then they are precise.● If measurements are not close to each other, but close to the true value, then they are accurate.Elements: the most basic units of matter. Composed of only one type of atom and cannot be broken down. Anything on theperiodic table. Example: Hydrogen, Carbon, Iron.Atoms: smallest chemical unit of matter or indivisible unit of an elementMolecule: formed when 2 or more atoms join together chemically.Compounds: at least 2 or more atoms of different elements combinedAll compounds are molecules but not all molecules are compounds.Pure Substance: same chemical composition throughout. Only consists of 1 element or a single compound. Cannot be separated.Homogenous Mixture: mixtures that are uniform and have same composition. Solutions.Heterogenous Mixture: Composition is not uniform. Easier to see the separate components in it.States of MattersolidClosely packedStrong molecularinteractionLeast amount ofkinetic energyliquidintermediateintermediateintermediategasWidely spacedWeak molecularinteractionGreatest amount ofkinetic energyPhysical Changes: do not change the chemical composition.-density -condensation-color -evaporation-melting point -dissolving-boiling pointChemical Changes: a change in the chemical composition.-reactivity with other compounds-combustion example: burning wood, iron rusting.SI UnitsTemperature● Kelvin is the unit mostly used in this course.● Density explains why ice can float on water.● Higher density sinks and lower density floats.Dimensional AnalysisX● Always want to begin with the units you are given in the problem and end up with on the top right in the units you wantto get to or the units the problem is asking for. When cancelling out units using conversion factors you place the sameunits that you want to cancel in the denominator.Chapter 2Atom: smallest unit of an element that retains its chemical propertiesAtomic Number: number of protons in an elementMass Number: total number of protons and neutronsProton: 1+, in the nucleusNeutron: 0, in the nucleusElectron: 1-, outside the nucleusCation: positive chargeAnion: negative chargeIsotopes: different number of neutrons, but same elementPeriodic TableAlkali metalsShiny, malleableGood conductors forelectricity and heatReact violentlyHalogensNonmetalDo not conductelectricityHighly reactiveNoble gasesNANADIFFICULT TOREACT!Valence Electrons are found in the outermost layer or shell of the element, while core electrons are located deeper down in theatom.● Look at the group number to help determine valence electron numberIonic Compounds● Ionic bonds transfer electrons completely. Wants to obey the octet rule and have 8 valence electrons.● Between metals and nonmetals.● Metals- want to be cations● Nonmetals/polyatomic ions (except ammonia)- usually the anions● Compound formulas are represented with the simplest ratio of cations to anions.● Naming: Cation is written first followed by the anion. Charges balance out to a net charge of zero to make thecompound neutral.● Roman numerals are used to indicate the charges on transition metals.● NO prefixes are used.Naming Monoatomic IonsCations (main group): add ion to the end -examples: Ca2+, Al3+Cations (transition metals): roman numerals because could have different charges, keep ion examples: Fe2+Anions: add -ide to the end and keep ion. Examples: H-, O2-Polyatomic IonsCovalent Compounds● Electrons are shared between the atoms● Between two non-metals● Naming: first element in the formula is named first and then the second element is used. Add -ide to the ending.● Use prefixes to show the number of each type of atoms.● Exception: Do not use mono on the FIRST element● Know the following common names:H2O- waterNH3- ammoniaNO- nitric oxideH2O2- hydrogen peroxideN2H4- hydrazinePrefixes● Allotropes: Same element but have different physical and chemical properties.● Hydrocarbons= CnH2n+2Inorganic Acids● Very strong acids.● H is always the first element.Chapter 3● 1 Mole= 6.022 x 1023atoms and/or molecules● Molar Mass: mass in g of one mol of that element. It is the sum of the atomic weights of all the atoms in a molecule.● ONE MOLE OF AN ELEMENT = ATOMIC WEIGHT IN GRAMSPercent CompositionX 100%Law of Conservation of Matter: matter can neither be created nor destroyed.Empirical Formula and Molecular FormulaEmpirical Formula: simplest whole number ratio of elements that are present in the compound. Does not provideinformation about the number of atoms in a moleculeMolecular Formula: tells you about the number of atoms in a molecule.Balancing Equations1. Start with atoms that only appear in ONE compound on the left and ONE compound on the right.2. Deal with the atoms that appear multiple times on either side later.3. If you have a free element, balance it last.4. SUBSCRIPTS ARE NEVER CHANGING, BUT COEFFICIENTS ARE.5. Coefficients should be the lowest possible whole numbers.Limiting Reagent/Reactant● The reactant that produces the smaller amount of product is the LIMITING REAGANT● The reactant that produces a larger amount of product is the REAGENT IN EXCESS. If the problem gives us more thanis needed this reagent is then EXCESS.● If something is EXCESS then it is not the limiting reagent● Limiting reagent is the one that runs out first● Burger example… the burger patties ran out so they were the limiting reagent● Do not forget to balance the chemical equation at the beginning!Percent Yield% yield = X 100%● Experimental yield: the