Chemistry 1 Lab Final Review PDF

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Accuracy difference between your measurement value of a property and its true value

Precision range of a repeated set of measurements of a property

Systematic Uncertainty causes results all high or all low definite cause machines fault

Random Uncertainty affects precision causes data to be scattered around a mean value

Density mass/volume

change in T cold Tfinal-Tcold

change in T hot T hot-Tfinal

gHchange T H gCchange T C

Standard Deviation series of repeated measurements is the uncertainty of the average value of the measurements

Intensive Property is indepent of the amount of substance present density and specific heat capacity

Extensive Property dependent on the amount of material used and thus cannot be used to characterize a substance mass and volume

specific heat capacity of lead= (mass of watercapacity of waterchange in temperature of water)/ (mass of lead*change in temperature of lead)

Calorimeter device used to measure the heat released (or absorbed)

Retention TIme the amount of time required for the compound to exit the column

Pure Substance type of matter that has a fixed composition

Compound chemically together

Mixture physically together

element

cannot be broken down smaller

%Composition of a component= mass of component(g)/total mass of sample(g)*100

%error= original mass-total mass/original mass*100

moles= mass/molar mass

atom ratio= moles X atoms/moles Y atom Periodic Law When the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

Paramagnetism Unpaired electrons; attracted to a magnetic field

Diamagnetism No unpaired electrons; repelled by a magnetic field

Effective Nuclear Charge Zeff= Z (atomic number)-S (core electrons)

Bonding Atomic Radius One-half of the distance between covalently bonded nuclei

Ionization Energy Minimum energy needed to remove an electron from an atom; endothermic

First Ionization Energy Energy to remove an electron from a neutral atom

Second Ionization Energy Energy to move an electron from a +1 ion

Electron Affinity Energy released when a neutral atom gains an electron; exothermic

Lattice Energy The energy required to completely separate a mole of a solid ionic compound into its gaseous ions

Coulomb's Law Eel=K(Q1Q2/d)

Crystal Lattice Maximizes the attractions between cations and anions, leading to the most stable arrangement

Electronegativity Measure of the pull an atom has on bonding electrons

Formal Charge =Valence number - # bonds - # lone electrons

Reaction Enthalpy =SUM[(energy of bonds broken) + SUM(energy of bonds made)

VSPER Electron groups around the central atom will be most stable when they are as far apart as possible

Linear Geometry Two electron groups around the central atom; Bond angle of 180 degrees

Trigonal Geometry Three electron groups around the central atom; 120 degree bond angle

Tetrahedral Geometry Four electron groups around the central atom; 109.5 degree bond angle

Trigonal Bipyramidal Geometry Five electron groups around the central atom; axial-equatorial bond angle is 90 degrees; eq-eq bond angle is 120 degrees

Octahedral Geometry Six electron groups around the central atom; bond angle is 90 degrees

Trigonal Pyramidal 3 bonds, one lone pair; bond angle less than 109.5 degrees

Bent 2 bonds, 2 lone pairs; bond angle less than 109.5 degrees

Seesaw 4 bonds, 1 lone pair

T-Shaped 3 bonds, 2 lone pairs

Linear 2 bonds, 3 lone pairs

Square Pyramidal 5 bonds, 1 lone pair

Square Planar 4 bonds, 2 lone pairs

Aufbau Principle Energy shells fill from lowest to highest energy

Sigma Bonds Head-to-head overlap; stronger than pi bonds

Pi Bond Side-to-side overlap

Law of conservation of mass Matter is neither created nor destroyed

Element Pure substance that cannot be broken down by a chemical change

Compound Pure substance formed by chemically joining two or more elements.

Atoms are submicroscopic particles

are the fundamental building blocks of all matter

Molecules two or more atoms attached together in a specific geometric arrangement

Homogeneous Mixture mixture that has uniform composition throughout

Heterogeneous Mixture mixture that does not have uniform composition throughout

Scientific Law

a summary of observations that combines all past observations into one general statement

Scientific Theory a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation

Law of Definite Proportions All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements

Law of Multiple Proportions When two elements (call them A and B) form two different compounds, the masses of B that combine with 1 g of A can be expressed as a ratio of small whole numbers

Dalton's Atomic Theory Each element is composed of tiny, indestructible particles called atoms.

All atoms of a given element have the same mass and other properties that distinguish them from atoms of other elements.

Atoms combine in simple, whole-number ratios to form molecules of compounds.

In a chemical reaction, atoms of one element cannot change into atoms of another element

Nucleus location of protons and neutrons

dense core of the atom

location of most of the atom's mass

Electron cloud location of electrons

comprises most of the atom's volume

Isotopes atoms of the same element that have a different number of neutrons

Atomic mass the weighted average of the masses of the naturally occurring isotopes of a particular element reported in atomic mass units

Metal Reflective

Conduct heat

Conduct electricity

Solids at room temperature

Metalloid Reflective

Semiconductors

Nonmetal Generally not reflective

Generally heat insulating

Generally not electrically conducting

Can be solid, liquid or gas at room temperature

Molar mass The mass of one mole of atoms

Numerically equal to the element's atomic mass

To name anion... change ending on the element name to -ide

Molecular compounds composed of molecules and almost always contain only nonmetals.

Ionic compounds almost always contain a metal with a nonmetal

Molecular formula give the exact number of atoms of each element in a compound.

Empirical formula give the lowest whole-number ratio of atoms of each element in a compound.

Solutions homogeneous mixtures of two or more pure substances

Dissociation When an ionic substance dissolves in water, the solvent pulls the individual ions from the crystal and solvates them

Electrolyte a substance that dissociates into ions when dissolved in water.

Nonelectrolyte may dissolve in water, but it does not dissociate into ions when it does so.

Precipitation Reactions When one mixes ions that form compounds that are insoluble (as could be predicted by the solubility guidelines), a precipitate is formed

Acids substances that increase the concentration of H+ when dissolved in water

proton donors

Bases substances that increase the concentration of OH− when dissolved in water

proton acceptors

Acid-Base Reactions the acid donates a proton (H+) to the base

Neutralization Reactions when solutions of an acid and a base are combined, the products are a salt and water

Oxidation-reduction reactions reaction involving transferring electrons from one atom to another

Oxidation Addition of oxygen

Losing electrons

Reduction Addition of hydrogen

Gaining electrons

Reducing agent The reactant that reduces an element in another reactant

Oxidizing agent The reactant that oxidizes an element in another reactant

Energy anything that has the capacity to do work

Work a force acting over a distance

Specific heat capacity the amount of heat energy required to raise the temperature of one gram of a substance 1 °C

Molar heat capacity the amount of heat energy required to raise the temperature of one mole of a substance 1 °C.

Hess's Law states that "if a reaction is carried out in a series of steps, H for the overall reaction will be equal to the sum of the enthalpy changes for the individual steps."

Standard enthalpy of formation the enthalpy change for the reaction forming 1 mole of a pure compound from its constituent elements

Wavelength the distance from one crest to the next

Amplitude the height of the wave

Frequency the number of waves that pass a point in a given period of time

Constructive interference When waves interact so that they add to make a larger wave

Destructive interference When waves interact so they cancel each other

Photoelectric Effect

It was observed that many metals emit electrons when a light shines on their surface

Bonding atomic radius one-half of the distance between covalently bonded nuclei

Bond length The distance between the nuclei of bonded atoms

Hybridization mixing different types of orbitals to make a new set of degenerate orbitals

Kinetic Molecular Theory The particles of the gas (either atoms or molecules) are constantly moving.

The attraction between particles is negligible.

When the moving gas particles hit another gas particle or the container, they do not stick, but they bounce off and continue moving in another direction

There is a lot of empty space between the gas particles

The average kinetic energy of the gas particles is directly proportional to the Kelvin temperature

Avogadro's Law The volume of a gas at constant temperature and pressure is directly proportional to the number of moles of the gas

V1 V2 --- = --n1 n2

Boyle's Law Pressure changes with the inverse of volume

P1V1 = P2V2

Charles' Law Volume increases linearly with temperature

V1 V1 --- = --T1 T2

Gay-Lussac's Law Pressure increases linearly with temperature

P1 P1 --- = --T1 T2

Combined gas law P1V1 P1V2

T1 T2

Ideal Gas Law PV=nRT What is another term for solubility? Miscibility (e.g. a substance is immiscible ... or miscible)

Identify the equation for boiling point correction. (760 mm Hg - given pressure in mm Hg) x (0.037 °C) = BP (correction) BP (initial) - BP (correction) = boiling point at given pressure

Name the six methods of separating materials. Decantation, filtration, extraction, sublimation, distillation, and sedimentation

Define the process of sublimation. A solid transforms to a gas and back to a solid without becoming a liquid.

Compare and contrast decantation and filtration. Decantation involves pouring a liquid out of a solution to retrieve only the solid; filtration utilizes a filtering device to catch a solid as a liquid passes through. Decantation is a slower process as it involves slowly pouring out amounts of liquid without allowing the solid to escape as well.

What occurs when a liquid is said to boil? Bubbles appear, rise rapidly to the surface, and burst.

Identify the equations for converting temperature. C = (F-32)/1.8 F = 9/5C + 32 K = C + 273.12

C = K - 273.12

What distinguishes a mixture from an impure substance? An impure substance has one component that is the majority whereas a mixture has similar amounts of each component

When will reactions proceed completion? Whenever one of the components is removed from the solution as seen in the formation of a gas or formation of a precipitate

What is the maximum percent yield of any reaction? 100%

Give criteria in terms of temperature changes for exothermic and endothermic reactions. Temperature increases for exothermic reactions as energy is released in the form of heat; the temperature decreases for endothermic reactions as energy is absorbed in the form of heat

What are the two types of reaction? Metathesis and redox

At the end of a chemical reaction, how are the remaining amounts of each reactant and product calculated? The limiting reagent is now at 0.00 grams from being used up, the excess reagent amount is calculated by converting the limiting reagent to the excess reagent and subtracting this amount from the original amount. Both products are calculated by converting from the limiting reagent to the product.

What is the average human body temperature in each unit? 37°C. 98.6°F. 310 K.

Define molarity and its relevant equation. Molarity is the amount of solute (in moles) divided by the amount of solvent (in liters).

M₁V₁ = M₂V₂

Why should more than one trial be run for each assignment? To ensure the first trial's results were not affected by outside factors and that the recorded results are consistent/proven to be correct each time the experiment is carried out

What is meant by the "stoichiometric point" of a reaction?

The equivalence point which is when the amount of two solutions are equal/have become neutral

What is the equation for density?

Density=mass/volume

Why should you never weigh a hot object?

Heat could damage the internal components of the scale and would not be weighed properly

Why is it necessary to calibrate instruments such as thermometers and volumetric glassware before use?

It is necessary to standardize values and ensure the instruments work properly.

What is precision? What is accuracy?

Precision is the reproducibility of a set of results; accuracy is how close the calculated value is to the actual value.

How do you find the mean weight and standard deviation from the mean?

Mean Weight = sum of all values/# of values

Standard deviation = (1) Absolute value of the subtracted mean weight from each value (2) Square each answer from part¹ and add the results (3) Find the square root of part² answer divided by # of original values - 1

When an analytic balance or scale weighs 5 grams to an accuracy of 0.1 mg, how many significant figures should the recorded weight be in?

Five because it records in grams but to the tenth of a milligram. The tenth of a milligram is equal to 0.0001 grams, so the recorded value is 5.0001 grams.

How many centimeters are in one inch? How many grams in a pound? 2.54 centimeters per inch; 453.6 grams per pound.

Recall the rules for significant figures.

- Multiplying/Dividing: Use least number of overall significant figures.

- Adding/Subtracting: Use least number of decimal places to decide amount of significant figures.

Define physical property and name all six physical properties that you can measure. Physical properties are properties that can be observed without changing the chemical composition. E.G: Density, solubility, viscosity, refractive index, melting point, and boiling point.

How do you find percent yield? Theoretical yield? Actual/theoretical x 100 = % yield Theoretical yield is the amount of product produced from completely consuming the limiting reagent.

Define properties and give examples. Properties are traits that can be used to identify a particular substance such as color, odor, density, etc.

What is the limiting reagent? How do you calculate for it? The limiting reagent is the reactant that limits the amount of product in a chemical reaction and is completely consumed. To identify the limiting reagent, convert both reactants to one product and compare which produces the least amount of product. The one that produces the least amount is the limiting reagent....