physical info Flashcards by Unknown Unknown

what is the shape and bond angle of a shape 4 bonding pairs and 2 lone pairs. draw this

square planar , 90deg
https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_ZCsGOhQF

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what is the shape and bond angle of a shape 3 bonding pairs and 2 lone pairs. draw this

T-shaped , less than 90deg
https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_ZCsGOhQF

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what is the shape and bond angle of a shape with 4 bonding pairs and 1 lone pairs. draw this

seesaw , less than 120 and less than 90deg
https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_ZCsGOhQF

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what is the shape and bond angle of a shape with 2 bonding pairs and 2 lone pairs. draw this

non linear or bent , 104.5deg
https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_ZCsGOhQF

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what is the shape and bond angle of a shape with 3 bonding pairs and1 lone pairs. draw this

Trigonal pyramidal, 107deg
https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_ZCsGOhQF

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what is the shape and bond angle of a shape with 6 bonding pairs and 0 lone pairs. draw this

octahedral, 90deg
https://www.physicsandmathstutor.com/chemistry-revision/a-level-aqa/physical-i/bonding-flashcards/ (slide81)

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what is the shape and bond angle of a shape with 5 bonding pairs and 0 lone pairs. draw this

trigonal bipyramid, 90 and 120deg
https://www.physicsandmathstutor.com/chemistry-revision/a-level-aqa/physical-i/bonding-flashcards/ (slide79)

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shape and bond angle of a shape with 4 bonding pairs and 0 lone pairs.draw this

tetrahedral , 109.5deg
https://www.physicsandmathstutor.com/chemistry-revision/a-level-aqa/physical-i/bonding-flashcards/ (slide77)

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shape and bond angle of a shape with 3 bonding pairs and 0 lone pairs.draw this

trigonal planar, 120deg
https://www.physicsandmathstutor.com/chemistry-revision/a-level-aqa/physical-i/bonding-flashcards/ (slide75)

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A sample of ethanedioic acid was treated with an excess of an unknown alcohol in the presence of a strong acid catalyst. The products of the reaction were separated and analysed in a time of flight (TOF) mass spectrometer. Two peaks were observed at m / z = 104 and 118. (a) Identify the species responsible for the two peaks.

[CH3OCOCOOH]+;(due to one ester on the end and the methyl group)

[CH3OCOCOOCH3] +; (ester and methyl on both ends)

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shape and bond angle of a shape with 2 bonding pairs and 0 lone pairs.draw this

linear, 180deg https://www.physicsandmathstutor.com/chemistry-revision/a-level-aqa/physical-i/bonding-flashcards/ (slide73)

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mass of 1 mole of an element/Avogadro’s constant =

mass of 1 atom of an element (use in tof to find mass) in g

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Relative formula mass (Mr) is

the average mass of a formula unit compared to 1/12th of the mass of an atom of carbon-12. Relative formula mass is used for ionic and giant covalent substances.

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Relative molecular mass (Mr) is

the average mass of a molecule compared to 1/12th of the mass of an atom of carbon-12.

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Relative atomic mass (Ar) - .

The weighted mean mass of an atom of an element, compared to 1/12th of the mass of an atom of carbon-12

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The y-axis of a mass spectrum shows the

relative isotopic abundance/ intensity

The x-axis of a mass spectrum shows the

mass/charge ratio (m/z), which equals the relative isotopic mass for the 1+ ions.

permanent dipoles

when a bond is polar it sometimes causes a permanent dipole

dipole-dipole force is

an intermolecular force that results from the attraction between molecules with permanent dipoles

what are the 3 intermolecular forces

vander -waals forces
dipole-dipole forces
hydrogen bonding

which is the strongest intermolecular force

hydrogen bonding

which is the weakest intermolecular force

vander -waals forces

van der Waals forces

Temporary dipoles are created by the random movement of electrons → induces dipole in neighbouring molecule → temporary induced dipole-dipole attraction aka van der Waals forces of attraction

hydrogen bonds

when hydrogen atoms covalently bonds to a very electronegative atom such as a O, N, or F atom and then the H atom forms an attractive force with another very electronegative atom and this attractive force is hydrogen bonding.

when calculating time of flight mass spectrum equations the equations you need include and what are their units

Ke=(1/2m) x v^2 and v=d/t t = time of flight (s) d = length of flight tube (m) Ek = kinetic energy (J) m = mass of ion (kg) v= velocity ( speed) (ms^-1)

how do you calculate lone pairs present

(total electrons present on the central atom( outer shell electrons) - electrons needed by the surrounding atoms)/2

calculate lone pairs on SO2

s - (2xo) 6-(2x2) = 2 electrons = 2/2 = 1 lone pair of electrons(since it is a pair)

Hydrogen bonding as a specific example of a super strong dipole only occurs when hydrogen is bonded to what 3 elements and why?

oxygen, nitrogen or fluorine as they are the most electronegative elements. (o,n,f)

an appropriate no. signifcant figures when asked in an exam

3 significant figures.

why is the electron configuration of cr and cu unusual Cr: 1s2 2s2 2p6 3s2 3p6 3d5 4s1 (instead of 3d4 4s2) Cu: 1s2 2s2 2p6 3s2 3p6 3d10 4s1 (rather than 3d9 4s2)

These exceptions occur because configurations with a half-filled (d5) or fully filled (d10) d sub-shell are energetically more favourable.

For transition metals forming ions what is the exception

the loss of electrons happens from the 4s orbital before the 3d orbital.

what shell is filled 1st 4s or 3d

The 4s sub-shell is filled before the 3d sub-shell because the 4s orbital has a lower energy than the 3d orbitals in neutral atoms. https://cognitoedu.org/coursesubtopic/c3-alevel-aqa_TaUnlVWt

he electron configuration of the iron atom is: 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2 what's the electron configuration for fe^3+

The resulting electron configuration of the Fe3+ ion is: 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 The 4s electrons are lost first. Then, one 3d electron is lost. as this is an exceptional rule For chromium and iron forming ions the loss of electrons happens from the 4s orbital before the 3d orbital.

why does the melting point from sulfur to cl decrease in period 3

sulfur is s8 and chlorine is Cl2 so sulfur is a larger molecule and hence greater vander waals forces.

What is the order of subshells from 4s to 7p

4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p

What is the order of subshells from 4s to 7p

4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p

Write the equations for the extraction of Titanium using Magnesium.

TiO2 + 2Cl2 + C → TiCl4 + CO2 TiCl4 (I) + 2Mg (s) → 2MgCl2 (s) + Ti (s)

Describe how to prepare 250 cm³ of an aqueous standard solution of ethanedioic acid containing an accurately measured mass of the acid.

✓ Accurately weigh out a dry sample of ethanedioic acid using a high precision balance ✓ Transfer to a beaker and reweigh weighing boat to determine mass transferred. OR rinse weighing boat into beaker ✓ Dissolve acid in a small volume of distilled water , stirring with a glass rod ✓ Transfer to a volumetric flask and rinse all equipment transferring rinsings too ✓Add deionised (aka distilled) water up to calibration line using dropping pipette at end Ensure meniscus rests on calibration line ✓ Stopper bottle and invert 10 times must be at end to homogenise solution

Describe how to prepare 250 cm³ of an aqueous standard solution of ethanedioic acid containing an accurately measured mass of the acid.

✓ Accurately weigh out a dry sample of ethanedioic acid using a high precision balonce ✓ Transfer to a beaker and reweigh weighing boat to determine mass transferred. OR rinse weighing boat into beaker ✓ Dissolve acid in a small volume of distilled water , stirring with a glass rod ✓ Transfer to a volumetric flask and rinse all equipment transferring rinsings too ✓Add deionised (aka distilled) water up to calibration line using dropping pipette at end Ensure meniscus rests on calibration line ✓ Stopper bottle and invert 10 times must be at end to homogenise solution