Chemistry PPQ

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/18

encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

19 Terms

1
New cards

bond length in molecules such as ozone

  • bond order 1.5

  • resonance/delocalisation fo a pair of electrons

  • all bonds have the same length

2
New cards

explain the dependence of the dissociation of oxygen, O2 and ozone, O3 on the wavelength of UV radiation

  • a shorter wavelength of radiation/UV is needed to break the bond in O2

  • O2 has a stronger bond compared to ozone (bond order 2 vs bond order 1.5)

  • ozone absorbes longer wavelengths of radiation than oxygen

3
New cards

types of correlation

  • negative correlation = as one thing decreases, another thing increases

  • positive correlation = as one thing increases, another thing also increases

4
New cards

comment [based on a graph about a conclusion]

  • evidence may support claim but might not prove it

  • answer why evidence supports claim but what further evidence is needed to prove the claim

5
New cards

state one assumption made for calculations involving weak acids and their Ka values

  • assume that there is neglible dissociation of the acid

6
New cards

state the composition of a buffer solution

  • combine acid with similar concentration of its conjugate base

7
New cards

Explain why Cu2+ is coloured with reference to its electronic structure

  • Cu2+ has partially filled d-orbitals

  • d-orbitals split

  • light energy is absorbed as electrons are promoted to a higher energy level

  • the energy gap/light absorbed between teh d-orbitals corresponds to a wavelength of light in the visible region of the spectrum

8
New cards

compare and contrast the IMF that result in ethenone being less volatile than carbon dioxide

  • both have london dispersion forces (due to having same number of electrons/similar Mr)

  • ethenone has dipole-dipole forces and carbon dioxide does not (due to C-H bond)

9
New cards

state one reason why gases become less ideal at higher pressures/lower temperatures

  • high pressure - gas particles are closer together and are influenced by forces of attraction therefore IMF are no longer neglible

  • low temperature - particles have lower kinetic energy, greater opportunity for IMF to have an effect and therefore they are no longer neglible

10
New cards

outline how two enantiomers can be distnguished

  • using a polarimeter

  • the enantiomers will rotate a plane of polarised light by the same angle but in opposite directions

11
New cards

explain why increasing the temperature increases the rate of a chemical reaction

more particles possess the necessary activation energy

more particles with E>Ea

frequency of collisions increases

more successful collisions per unit time

12
New cards

state the reagent for the conversion of the compound C3H8O into C3H6O

K2Cr2O7 and acidified/H+

13
New cards

explain why the compound C3H8O has a higher boiling point than C3H6O

hydrogen bonding is stronger than dipole-dipole

C3H8O has hydrogen bonding whilst C3H6O doesn’t

14
New cards

outline two laboratory methods of distniguishing between solutions of citric acid and hydrochloric acid of equal concentration, stating the expected observations

  • hydrochloric acid will react faster and with more effervescence with a reactive metal than citric acid

  • hydrochloric acid will conduct electricity better than citric acid

  • [citric acid has a higher pH because it is a weaker acid]

15
New cards

Describe using a suitable equation how the buffer solution formed during the titration resists pH changes when a small amount of acid is added

  • equilibrium shifts to the ethanoic acid side

  • CH3COOH/CH3COO- ratio virtually/mostly unchanged

  • [added acid is neutralised by ethanoate ions]

<ul><li><p>equilibrium shifts to the ethanoic acid side </p></li><li><p>CH<sub>3</sub>COOH/CH<sub>3</sub>COO<sup>-</sup> ratio virtually/mostly unchanged </p></li><li><p>[added acid is neutralised by ethanoate ions]</p></li></ul><p></p>
16
New cards

state the electronic configuration of the Cu+ ion

1s22s22p63s23p63d10

[normal Cu atom has 4s1 subshell]

17
New cards

Describe how the blue colour is produced in the Cu(II) solution

  • ligands cause d-orbitals to split

  • light absorbed as electrons are promoted to a higher energy level

  • energy gap corresponds to orange lift in the visible region of spectrum

  • colour observed is complementary to the colour absorbed - blue

18
New cards

Deduce why the Cu(I) solution is colourless

full 3d sublevel/orbitals (3d10)

19
New cards

Examine the relationship between the Bronsted-Lowry and Lewis definitons of a base referring to the ligands in the complex ion [CuCl4]2-

  • ligand/chloride ion is a Lewis base as it donates an electron pair

  • chloride ion is not a Bronsted-Lowry base as it does not accept a proton

  • Lewis base definition is broader/extends further than the Bronsted Lowry definition