Thread Starter Electronegativity - A level AQA Follow 4 minutes ago 4m ago Quote: Originally Posted by Rohan007best Can someone please explain how the atom gets smaller across a period, there's more e-s and protons so surely it should say atoms become larger?Attachment 1086184 As you go across the period the number of protons increases as well as electrons but because the electrons are added to the same energy level (think back to adding electrons to a ring around the nucleus to visualise) the atomic radius won't increase but since there are more protons, the nuclear charge w ..read more

Thread Starter Bonding A level chem - AQA Follow 23 minutes ago 23m ago If you melt or boil a simple covalent compound u overcome the intermolecular forces but if its a giant covalent substance do u overcome the covalent bonds or break the covalent bonds? Because some textbooks use the term overcome and some use break. But I was told u cant break intermolecular forces u overcome them so is this the same with covalent bonds ..read more

Thread Starter chem help Follow 1 hour ago 1 hour ago Quote: Originally Posted by tuxedo- 1. Calculate moles of NaOH titrated. (n=cv) 2. Work out therefore the moles of HCl reacted using the ratio in the reaction. 3. Calculate the moles of HCl added to the aliquot of solution A. 4. Subtract 2 from 3. (moles in 3 - moles in 2) This gives the moles of acid that reacted with M2CO3. 5. Using the ratio in the reaction, work out the moles of M2CO3 that reacted with this many moles of acid. 6. Multiply this by 10, to get moles of M2CO3 in the 100ml solution. 7. Work out the Mr of M2CO ..read more

Thread Starter [Al(H2O)3(OH)3] Follow 10 minutes ago 10m ago Quote: Originally Posted by UtterlyUseless69 My initial guess would be that since Al^3+ is very small and OH^- is charged, fitting 6 OH^- ions around the aluminium would be very difficult due to the overwhelming electrostatic repulsion. A similar explanation would probably also suffice for the fact that [Al(OH)5]^2- isn’t formed. That would make sense, thanks for the explanation ..read more

Thread Starter Question on standard solutions Follow 2 hours ago 2h ago In the Proteinuria assay practical you made up a number standard solutions of serum albumin to perform your tests. What volume of a 4% solution of albumin stock solution would be needed to make up 1 mL of 0.2% standard solution of albumin. Is the answer for this 50 ul (with 0.95mL distilled water)? In the cholesterol assay practical you made up a number standard solution of cholesterol to construct a standard curve. What volume of a 0.5% cholesterol stock solution would be needed to make up 1 mL of standar ..read more

Thread Starter Random OCR A-level organic mechanism reactions paper 3 Follow 1 minute ago now How do I tackle the random organic mechanism reactions given in OCR A-Level chemistry Paper 3? because it is confusing to understand it, is there any tips or documents or like lists which OCR has provided in which random reactions they could assess us on in paper 3 which is outside the spec ..read more

Thread Starter A level chem ether structure Follow 15 minutes ago 15m ago How do I draw this structure ..read more

Thread Starter Are H or He in the s block? Follow 59 minutes ago 59m ago Quote: Originally Posted by Bertybassett In a recent exam question, it asked for the element in the s block with this highest ionisation energy. The answer was Be. The periodic table provided by aqa doesn't show he and h directly in the column of the s block, but both of their highest energy electrons are in the s sub level. ik you probably know the answer now lol but helium and hydrogen are s-block elements but the question asked for s-block metals ..read more

Thread Starter OCR A level Chemistry Year 1 and AS Kerboodle book Follow 1 hour ago 1 hour ago Do you know from where to get the answers for the paper 1 and paper 2 style questions ..read more

A ..read more