NUMS chemistry Flashcards

Question

which reaction differentiates alcohols and phenols?

Answer 1

**halogenation** - phenols react with bromine water to give a white precipitate. alcohols do not have any reaction with bromine water

Answer 2

**low IMF's**: weaker the attraction b/w molecules, more ideal the gas behaves **small molecular size**: smaller molecules behave more ideally b/c volume is negligible **most ideal gas is He** - not hydrogen b/c exists as diatomic but He exists by itself. is second on the periodic table

Answer 3

**reaction order**: overall reaction order is sum of exponents in rate law, determined by experimental data of how rate changes as concentration changes **unit of rate**: M/s **zero order**: rate does not depend on concentration of the reactant - k units: **M/s** - reaction doubled = no effect on rate **first-order**: rate is directly proportional to the concentration of the reactant - k units: **1/s** - reaction doubled = rate doubles **second order**: rate is proportional to the square of the concentration of the reactant ( - k units: **1/M·s** - rate double = reaction increase by factor of 4 **third order**: k units are **1/M²·s** - rate double = reaction increase by factor of 8 (cubed)

Answer 4

reactivity b/c gets larger so harder to hold onto electrons and they can react more

Answer 5

the relationship b/w quantities of substances in a chemical reaction

Answer 6

more covalent character = less ionic **more covalent character**: small and highly charged basically, ionic character decreases as you move left to right and increases as you move top to bottom of periodic table

Answer 7

**nitrogen** N2 - 78% of air O2 - 21% of air Ar - 0.93% (third most abundant)

Answer 8

1836 times heavier

Answer 9

wood spirit = methanol b/c earliest method of it was by destructive distillation of wood formula = **CH3OH**

Answer 10

**bond energy**: amount of energy required to break one mole of bonds in a molecule - higher bond energy = stronger bond shorter bond length due to size of molecule = greater bond energy more polar (more electronegative) = more bond energy *ex. HF has greater bond energy than HCl*

Answer 11

occurs at **4ºC** - water has a unique property where its density increases as it cools down from a higher temp, but only up to 4ºC - **below** 4°C, water starts to expand again as it continues to cool, which is why ice is less dense than liquid water

Answer 12

alkenes (double bonds) - geometric isomerism is most present in C=C bonds b/c of their inability to rotate relative to one another about the double bond *geometric isomerism is the cis and trans one*

Answer 13

involves transforming non-enolizable aldehydes (aldehydes without alpha-hydrogens= hydrogens attached to the carbon next to the carbonyl group) into alcohol and carboxylic acid salts **50% NaOH** is usually used to initiate this reaction

Answer 14

used to create larger molecules by joining 2 smaller molecules (typically aldehydes or ketones) together **how it works**: two molecules of an aldehydes or ketones w/ alpha hydrogens react in the presence of a base - forms a new carbon-carbon bond between them, creating a larger molecule

Answer 15

chemically organic functional group composed of a carbon atom double-bonded to an oxygen atom --> [C=O] simplest carbonyl groups are **aldehydes [R-C=O-H] and ketones [R-C=O-R]** usually attached to another carbon compound

Answer 16

used to remove oxygen from a carbonyl group (like in aldehydes or ketones) and turn it into a simple hydrocarbon **using an acid** reaction uses **zinc amalgam (Zn(Hg)) and hydrochloric acid (HCl)**

Answer 17

similar to clemmensen reduction, it **removes oxygen** from a carbonyl group to turn it into a hydrocarbon, but **using a base instead of acid** reaction involves treating the carbonyl compound with hydrazine (NH₂NH₂) and a strong base like KOH

Answer 18

process of combining an organic acid (RCOOH) with an alcohol (ROH) to form an ester (RCOOR) and water **occurs in the presence of carboxylic acid and alcohols**

Answer 19

**AlCl₃ (Aluminum Chloride)**: often used in Friedel-Crafts reactions, which involve *attaching alkyl or acyl groups to a benzene ring* **NaOH (Sodium Hydroxide)**: a strong base known to break down compounds, which might lead you to think it could simplify larger molecules into smaller molecules

Answer 20

NaOH producing a simple molecule from a more complex one so need a strong base known to break down compounds chlorobenzenes and cumene are both complex molecules & would be unlikely that you need them to produce a simple molecule like benzene

Answer 21

states that the total enthalpy change (heat content) for a chemical reaction is the same, no matter how many steps or stages the reaction is carried out in **application**: used to calculate the heat of a reaction that is difficult to measure directly by adding up the heats of reactions that are easier to measure

Answer 22

states that amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid According to Henry's Law, **if you increase the pressure of the gas over the liquid, more of the gas will dissolve in the liquid** formula: **C = kP** C = concentration of gas in the liquid k = henry's law constant (specific to each gas-liquid pair) P = partial pressure of the gas

Answer 23

**s block**: groups 1 and 2 and helium **p block**: groups 12-18 (up to halogens, starting from Boron) **d block**: groups 3 to 12 (the transition metals) **f block**: lanthanides and actinides (usually shown below the main table)

Answer 24

alkanes (single bonds): - each carbon is **sp³** hybridized - bond angle: **109.5º** alkenes (double bonds): - each carbon in double bond is **sp²** hybridized - bond angle: **120º** alkynes (triple bonds): - each carbon in triple bond is **sp** hybridized - bond angle: **180º**

Answer 25

H - 1 He - 4 C - 12 N - 14 O - 16 F - 19 P - 31 S - 32 Cl - 35.5

Answer 26

**pressure of multiple bonds**: multiple bonds (double, triple) have shorter bond lengths compared to single bonds **nature of hybridization**: as s character increases (sp, sp2, sp3..), bonded atoms pull closer **difference in electronegativity**: more electronegative atom pulls electrons closer, shortening bond length *ionization energy is energy required to remove an electron - which affects reactivity of atom, but not directly the bond length*

Answer 27

only shapes, not bond energy - used to predict gerotrey of molecules

Answer 28

refers to a carbonyl group attached to an alkyl group *commonly associated with ketones and aldehydes*

Answer 29

intermolecular forces

Answer 30

**temperature**: as temp increases, vapor pressure increases b/c more molecules escape into vapor phase **IMF's**: as IMF's get stronger, vapor pressure decreases b/c fewer molecules escape **density of liquid**: vapor pressure not directly dependent on density, but density can influence how many molecules are in a given volume *surface area of liquid does not have an impact on vapor pressure b/c not influenced by size or shape of liquid's exposed surface area*

Answer 31

smaller the ion & higher the charge, greater the lattice energy