u/Altruistic-Elk-5411

circular motion

conditions for ucm: velocity perpendicular to acceleration, magnitude of velocity must be constant, direction of velocity constantly changes
why the force's titled: vertical component of lift force balances weight, and horizontal component provides centripetal force
direction of resultant- horizontal arrow pointing to the left, towards centre of circle
a= 4.5
theta= 24.6, dont quite remember tho

gravitation

four field lines acting downwards
m= 5.9 something x 10^24 kg
phi = -6.25 x 10^7 J/kg
gpe = -4.61 x 10^9 J

thermal

specific heat capacity- energy per unit mass per unit temperature change
work done is positive
prove increase using v proportional to t, internal energy is equal to ke in ideal gas, something along those lines
q = -1226 something like that
c = 5200
c is greater

vol occupied by gas negligible compared to vol of containter
collisions are elastic
other points also applicable

change in p = 2mu
t = 2L/u
mean force = mu^2/L
pressure is force per unit area so p = mu^2/L^3
L^3 was volume
mean square speed since all dimensions considered
1/3 since equal speed for all dimensions
N because masses of all molecules need consideration
not sure tho

this is all i remember in depth, do ya'll remember your answers? what do you think the gt is going to be?

hi there!

i was wondering if anyone knows any sites where the solved solutions of papers for mj 26, that have already been conducted, are available?

last year, crack-a-level was providing them, but don't see them active this year! please do let me know, especially for 9709, 9701, and 9702.

thank you so much!!

hi there!

i'm an a level student who applied for the mfds program at uni wien, and was wondering if anyone got a confirmation email that the test is occurring? because, on their website it mentions that if sufficient people didn't apply- the admissions test wouldn't be conducted?

also, how are ya'll studying for the test? does anyone know if the a level curriculum is similar to the test's contents? looked at the syllabus, but still worried about what may appear on the test.

thank you so much!!

Complete the electrons in boxes diagram in Fig. 1.1 to show the electronic configuration of a Cr 3+ ion [1]

Type of bonding involved - Dative covalent [1]

* State two other chemical properties of a transition element. [2]
forms coloured compounds, behaves as a catalyst, variable oxidation states, etc

* Explain why transition elements have variable oxidation states. [1]
3d and 4s subshells are similar in energy

* Explain why transition elements can form complex ions. [1]
vacant d orbitals are energetically accessible

* Describe the mode of action of a heterogeneous catalyst. [2-3]
adsorption, bond weakening, desorption

* Describe and explain how the solubility of the Group 2 sulfates varies down the group. [4]
enthalpy of solution becomes more endothermic down the group
both enthalpy of lattice and hydration become more exothermic
but enthalpy of hydration becomes more exothermic quicker
so enthalpy of solution becomes more endothermic

* Suggest a suitable reagent for the formation of [Co(H2O)4(OH)2] [1]
naoh

* Magnesium hydroxide, Mg(OH)2, is only slightly soluble in water. The value of the solubility product, Ksp, of Mg(OH)2, is 1.0 x 10-33 at 298K

(i) Complete the expression for Ksp of Mg(OH)2. Include the units. [2]
ksp = [mg][oh]^2, mol^3dm^-9

(i) Use your answers to (d)(i) and (li) to calculate the value of Ksp of Mn(OH), at 298K. [1]
forgot my ans for this

* Define standard electrode potential, E°, including a description of standard conditions. [2]
the emf of half cell compared with she under std conditions of 1mol/dm3 solution conc, 298 K, 1 atm

* Explain what is meant by optically active. [1]
a mixture of enantiomers that rotates plane of polarised light in a specific direction

* Describe what is meant by a racemic mixture. [1]
an equimolar mixture of enantiomers that cancels out the rotation of plane polarised light

* Why Fe3+ is acidic [1]
donates protons? wasnt sure

* Fe2+ or Fe3+ which is more acidic [2]
fe3+. forgot my explanation.

* •State what is meant by partition coefficient, Kpc. [1]
the ratio of the conc of solute in two immiscible solvents

* Would kpc increase / decrease/ no change with butanioc acid [1-2]
kpc of butanoic is greater because more soluble in organic solvent

* •Describe the relative basicities of P, Q, Amonnia. Explain your answer. [4]
ammonia was in the middle. dont remember what p and q were. but had to mention basicilty is the ability to accept h+. the +I effect of alkyl group increase e density on N, easier to accept H+ , delocalisation of lone pair on N into pi system of benzene decrease e density on N making to difficult to accept h+

* •Why is Agl colourless?Explain why this complex is colourless. [2]
incorrect frequency of photon absorbed- so no electron promotion. d orbital was stable.

* Order of reaction - Use the data in Table 5.1 to deduce the rate equation for this reaction. Explain your reasoning. [3]
all were first order.

* for a different experiment 5, calculate the intial rate [2-3]
k was 1.25, so rate was 1.953 x 10^-2 mol^3dm^-9

* An excess of Br, (aq) is added to separate samples of CH NH, and benzene. - C6H5NH, reacts readily with Br, (aq) to form organic product M. State the expected observations for this reaction. Draw the structure of M. [2]
white ppt observed, tribromophenol

* State what is meant by isoelectric point. [1]
ph at which the amino acid exists as a zwitterion

* Draw the structure of alanine at pH 10 [1]
negative charge on coo

* The ionic radius of Pb is 0.120 nm compared to 0.133 nm for K+ and one more metal. suggest which metal carbonate would be more stable. [2]
the one with the highest ionic radius was most stable, due to the lower charge density, weak polarisation of anion, and so less distorition- more stable compound

* Table 2.1 shows electrode potentials for some electrode reactions. Write two equations and explain whether feasible. [3]

forgot what i used, but e cell had to be more than 0 to be feasible

* ldentify the number of different carbon environments present in X [1]
5

* Identify the substance that gives the small peak at 6 = 0 [1]
tetramethylsilane

* •When D20 is used as a solvent, the spectrum obtained is different. Describe this difference and explain your answer. [2]
1- 5 chemical shift range, d2o disapperas peaks for lablie protons, forgot the group

* Splitting patterns [4]
doublet, multiplet, triplet, triplet

please do feel free to add more questions, and your answers? these are all the answers i remember, saw the questions written on discord heh.

can anyone please help me calculate how many marks i scored so far to these ones at tleast? thank you.

if i got like a 103 raw mark for as, would a 60-65 in todays paper 4 and like a 20 in p5 be enough for an a?

i found the paper hard. especially the calculation for % mass and kpc- found moles of both, and subtracted more from lower to find excess, and other working tho. will i still get some marks for that?

thanks y'all. quite worried tbh.

can anyone who watched the entire video let me know if there are any in the vid? i have massive arachnophobia, so haven’t even been able to open it.

thank you!!

what do y'all think that thresholds gonna look like for a*? it was 222 for mj 25? think it's gonna be higher?

hi there.

i (18F) was diagnosed with CFS a little more than two years ago (symptoms began appearing three years ago), and unsurprisingly, it's been a horrible experience. but recently i've been experiencing horrible night terrors every night, and i'm really scared to fall asleep because of this- resulting in even more fatigue and agony throughout the next day.

i'm not really the type to post, but today's been unbearable, and it's exam week- so i just needed some advice and help (i was wondering if this has something it do with stress too? but it sort of has been coming and going for the past few months- it started back in dec of last year)

any advice and thoughts would be much appreciated. thank you so much.