Chemistry 1331 - Study guides, Class notes & Summaries

True value - The accepted value for a measurement accomplished by repeating measurement or theoretically from first principles Accuracy - How close a measurement is to the true value Precision - How well multiple measurements agree with one another Least sig figs - Rules for mathematical operations: When multiplying or dividing the answer always has the same number of sig figs as the calculation with the _____ Least decimal places - Rules for mathematical operations: When adding or sub...

All of them - what measured quantity have uncertainity? Certain digits - Digits which are not estimated Uncertain digits - Digits which must be estimated True value - The accepted value for a measurement accomplished by repeating measurement or theoretically from first principles Accuracy - How close a measurement is to the true value Precision - How well multiple measurements agree with one another Least sig figs - Rules for mathematical operations:

Isotopes - Same number of protons and electrons but different number of neutrons. Therefore, different mass. Ex: N=18 A=18+17=35 => Cl-35 N=20 A=20+17=35 =>Cl-37 Relative mass=Atomic Mass - Weighted avg= sum(mass of isotope)(fraction of atoms) Ex: Chlorine 3/4 are Cl-35, 1/4 are Cl-37 Atomic Mass=(35*.75)+(37*.25)=35.5 Identify - Alkali metals (H not alkali metal) Alkaline earth metals Transition metals Triels/Icosagens: boron group Tetrels/Crystallogens: carbon group

VSEPR - Valence shell electron repulsion: place the electron around the central atom as far from each other as possible Electron-group arrangement - The 3-D geometric shape that the bonding and nonbonding electron occupy Molecular shape - The 3D shape that only the bonded atoms occupy, i.e. What the molecule "looks like" AXmEn notation - A=central atom

Mixtures - Variable Composition Pure Substances - Constant Composition Homogenous Mixture - A mixture in which the composition is uniform throughout Heterogenous Mixture - A mixture with uneven distribution of different substances, solids, liquids, gases. Elements - A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions. Compunds - A pure substance that contains two or more different elements in a fix porportion

True value - The accepted value for a measurement accomplished by repeating measurement or theoretically from first principles Accuracy - How close a measurement is to the true value Precision - How well multiple measurements agree with one another Least sig figs - Rules for mathematical operations: When multiplying or dividing the answer always has the same number of sig figs as the calculation with the _____ Least decimal places - Rules for mathematical operations: When adding or sub...

VSEPR - Valence shell electron repulsion: place the electron around the central atom as far from each other as possible Electron-group arrangement - The 3-D geometric shape that the bonding and nonbonding electron occupy Molecular shape - The 3D shape that only the bonded atoms occupy, i.e. What the molecule "looks like" AXmEn notation - A=central atom X= bonded atom E=lone pair m & n= how many of each you have X & E are referred to as "electron group" Steric number - The numbe...

All of them - what measured quantity have uncertainity? Certain digits - Digits which are not estimated Uncertain digits - Digits which must be estimated True value - The accepted value for a measurement accomplished by repeating measurement or theoretically from first principles Accuracy - How close a measurement is to the true value Precision - How well multiple measurements agree with one another

Mixtures - Variable Composition Pure Substances - Constant Composition Homogenous Mixture - A mixture in which the composition is uniform throughout Heterogenous Mixture - A mixture with uneven distribution of different substances, solids, liquids, gases. Elements - A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions. Compunds - A pure substance that contains two or more different elements in a fix porportion

Isotopes - Same number of protons and electrons but different number of neutrons. Therefore, different mass. Ex: N=18 A=18+17=35 => Cl-35 N=20 A=20+17=35 =>Cl-37 Relative mass=Atomic Mass - Weighted avg= sum(mass of isotope)(fraction of atoms) Ex: Chlorine 3/4 are Cl-35, 1/4 are Cl-37 Atomic Mass=(35*.75)+(37*.25)=35.5 Identify - Alkali metals (H not alkali metal) Alkaline earth metals Transition metals Triels/Icosagens: boron group Tetrels/Crystallogens: carbon group