Tutor profile: Kito G.
Subject: Organic Chemistry
What are the CARDiO rules and what do they mean?
The CARDiO rules determine the acidity of an organic molecule's hydrogen. These rules can be used to find the most acidic hydrogen on a molecule, or when given two similar molecules, which one is likely to be more acidic. C: Charge The more positive a charge on an organic molecule, the easier it is to remove a proton from it, meaning it is more acidic. The more negative the charge, the more difficulty proton removal will be, meaning it is less acidic. A: Atom The type of atom that a hydrogen is bonded to will help determine whether that hydrogen is more or less acidic. If the non-hydrogen atom has a larger atomic radius, then the hydrogen will be more acidic. As we go to the right and down the periodic table, radius increases, so we can assume that acidity will increase for hydrogens bonded to those atoms as well. R: Resonance If, when the proton is removed and the atom that it was removed from has a negative charge that can be spread about with resonance, then that hydrogen will be more acidic than one that cannot. Di: Dipole/ Inductive effect When a molecule has a very electronegative atom attached close to an acidic hydrogen, electrons will be pulled away from that hydrogen the proton will be more likely to leave the molecule, making the molecule more acidic. O: Orbitals An atom with a hydrogen attached will be able to lose that hydrogen more easily if the atom is making a higher order bond to another atom. The higher the order (double bond, triple bond) the more likely it will be that the proton can leave, and thus the higher acidity of that proton. This is because higher-order-bonded atoms can carry negative charges more easily than those with lower orders.
What are three of the main types of chemical reactions? Name each one, describe the characteristics of each (along with any other important information), and give one balanced example of each.
Single replacement reaction: A reduction-oxidation reaction in which a charged species (cation or anion) travels from an oppositely charged species in one reactant to an uncharged, separate reactant. Cu(s) + 2AgNO3(aq) --> Cu(NO3)2(aq) + 2Ag(s) Double replacement reaction A reaction in which the cations of two reactants swap with each other, sometimes producing a precipitate. PbSO4(aq) + 2NaCl(aq) --> PbCl2(s) + 2Na2SO4 Combustion reaction A reaction in which a compound (often a carbohydrate) reacts with an oxidizer (often oxygen) to create a new compound and heat. In the case of carbohydrates and oxygen, water and carbon dioxide are produced. 2C6H14 + 19O2 --> 12CO2 + 14H20
Subject: Basic Chemistry
What was the premise of Rutherford's gold foil experiment and what did it teach us about the structure of the atom?
Rutherford's experiment consisted of an extremely thin gold foil surrounded by alpha-particle detectors on all sides. Aimed at the foil was an alpha-particle source, which shot a beam of alpha-particles directly at the foil. When the foil was struck with the particles, most went through, but some small fraction shot off to the sides, or back toward the particle source at an angle greater than 90 degrees. From this, Rutherford derived an equation and concluded that alpha particles, which are positively charged, must be repelled by something else that is positively charged within the gold atoms. And, judging by the small fraction of reflected particles, the part of the atom that is positively charged must be small and the majority of the atom's volume must be empty space. Rutherford came up with a model that represented an atom with a small, positively charged center surrounded by mostly empty space, and he named the positively charged center the nucleus.
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