CHEMISTRY COMMUNITY

Keshav Patel 14B 2B

A reaction without a catalyst would have a smaller rate constant for sure but with a catalyst it’s important to distinguish that this new reaction takes an entirely different path. Furthermore, yes temperature increase does increase K.

Keshav Patel 14B 2B

Intermediates are molecules that appear in the initial reaction but do not end up in the final reaction. In the first few steps they become products and become cancelled out so they are not seen in the final reaction.

Keshav Patel 14B 2B

It tells us how the reactant affects the reaction rate. Different orders have different equations that are equal to the slope which is the reaction rate.

Keshav Patel 14B 2B

Activation energy is in the units kJ/mol.

Keshav Patel 14B 2B

Basically to activate the reaction you need lots of energy. Because energy there’s not always huge amounts of available energy the reaction is much slower hence the slower reaction rate

Keshav Patel 14B 2B

The first equation you use for zero order reactions while the second is for first order reactions. I was confused on this as well!

Keshav Patel 14B 2B

X is the time while the Y is the concentration the slope of the graph shows the Rate of the reaction. Important to realize the graph goes up and down over time because the concentration fluctuates as well.

Keshav Patel 14B 2B

When you have multiple reactants you have to look at the reactant that has the least amount almost like looking at the limiting reactant back from foundations. The smallest one will have the largest affect on the reaction because once it runs out, the rest become pointless until a reverse reaction t...

Keshav Patel 14B 2B

The rate constant K can only change when temperature changes!

Keshav Patel 14B 2B

pH level measures the amount of hydronium ions within something or determining the strength of the acid. pOH measures the strength of a base and the amount of hydroxide present on a scale of 1-14 for both.

Keshav Patel 14B 2B

They are not interchangeable!!!! At all! Both will give you different solutions!! Make sure you use log and ln appropriately, only in one equation you use the log when you have the .059V/n in the Nernst Equation is when you use log(q) otherwise do not!

Keshav Patel 14B 2B

The n is referring the moles of electrons being transferred so when you look at a redox reaction first look at the charges from the left and the right. If the right is stable and the left is 3- then there was a transference of 3 electrons.

Keshav Patel 14B 2B

E naught is in standard conditions meaning 1 atm , 298k but E is not that is why you have to find the new temperature and different pressure when you use the E equation.

Keshav Patel 14B 2B

There will be instances where we have to solve for the Standard Potentials ourselves using the equation but if he does not want to have super long questions he will give us the stand potential to find the solution to the question using the standard potentials to find the total energy for instance.

Keshav Patel 14B 2B

Oxidizing agent is being reduced which allows ANOTHER element to be oxidized! Confusing but interesting how it works out.

Keshav Patel 14B 2B

You should know most oxidation numbers from fundamentals of 14A by looking at the periodic table of elements of what an element wants and how it can achieve its octet by losing or gaining electrons.

Keshav Patel 14B 2B

The difference between irreversible and reversible reactions is that irreversible reactions happen very fast and the energy change is immediate. The reversible reactions are very slow and as heat is transferred through the reaction. It absorbs heat from the environment and this makes reversible reac...

Keshav Patel 14B 2B

Q is the equilibrium constant. If you have molar concentrations of the reactants and products you can make it reactants/products and put them to the power of number of moles. That gives you the Q value.

Keshav Patel 14B 2B

Reactions are spontaneous only when the reaction still occurs even when there is no additional input of energy.

Keshav Patel 14B 2B

If the work is negative than that means the system is doing work. When it does work it loses or uses energy hence the reason its negative.

Keshav Patel 14B 2B

The second law of thermodynamics states that entropy increases with spontaneity. The equation is S = qrev/t.

Keshav Patel 14B 2B

Entropy values are always positive values because spontaneous values need to be constant.

Keshav Patel 14B 2B

It’s not the size of the atoms but the size of the molecules. Larger molecules typically have a larger entropy.

Keshav Patel 14B 2B

The change in U = q+w but also if the temperature is stable then U remains 0 so -q = w.

Keshav Patel 14B 2B

The expansion and compression are done in such small rates back and forth that it’s infinitely small hence 0 because truly there is no real change. I think of it like chemical equilibrium. The forward and reverse reactions rates are equal the reactions don’t just stop.

Keshav Patel 14B 2B

If you are pulling the piston it makes the work negative as their is volume expansion if your system is the within the piston and it’s pressure.

Keshav Patel 14B 2B

Reversible reactions are slow and allow heat to come into replace the energy lost during expansion while irreversible reactions are very fast.

Keshav Patel 14B 2B

Delta U is just the change of energy in a system, q + w which is heat + work.

Keshav Patel 14B 2B

Negative work means that’s how much energy is needed, so if you have a larger negative value, it means that the reaction or whatever you’re doing needs more energy.

Keshav Patel 14B 2B

The way to look at combustion is by looking at the products and reactants. If the products don’t have bonds, then the products combusted and released heat to break their bonds.

Keshav Patel 14B 2B

Closed system still can interact with surroundings just in a sealed container. So it’s like a water bottle with the cap, the amount of water cannot increase with rain but some of the water can evaporate because of the sun.

Keshav Patel 14B 2B

Heat capacities cannot be negative because it is the amount of temperature to be either gained or lost to change a temperature. So it is always a positive value.

Keshav Patel 14B 2B

Calorimeter calculate the amount of heat given off in a reaction, these are very useful because no heat is lost to surroundings nor is heat absorbed.

Keshav Patel 14B 2B

Q represent heat, while H is a state function for enthalpy meaning the change in amount of heat.

Keshav Patel 14B 2B

First recognize if the reaction is endothermic or exothermic. If it takes heat to make products and you add more heat, then the reaction will shift towards the products. And vice versa.

Keshav Patel 14B 2B

Vapor and Gas are the same thing, if it’s water vapor it is water in its gas phase.

Keshav Patel 14B 2B

Delta H is referring to only the heat exchanger while Delta U incorporates all types of energy exchanges.

Keshav Patel 14B 2B

Enthalpies are state functions! That’s why they can be added together in order to solve for unknown enthalpies.

Keshav Patel 14B 2B

Very important because if you do the -log of that you will get 14 which explains why pH and pOH add up to 14 as well. We can use 1*10^-14 directly and find the kA and kB values as necessary.

Keshav Patel 14B 2B

Well technically all of these acids and bases can fit any of the definitions but since we look at the proton moving from the acid or base it is a Bronsted Lowry, however it’s the same thing as Lewis acid and base because anytime a proton it is always a pair of electrons being a full shell for the Hy...

Keshav Patel 14B 2B

You have to do the -log of the concentrations of OH- and H30+ to find the pH or pOH.

Keshav Patel 14B 2B

Anytime you have the original species that’s already in solution, and for example say it’s pH is 3 and you put in another acid that is pH 4, solution is not charged because there will not be anymore hydroniums being formed because it is already more acidic than the acid being placed in. Hope this he...

Keshav Patel 14B 2B

Do your ice table and find the concentration of Hydroniums in the solution, after that it’s easy just multiply by 1/100.

Keshav Patel 14B 2B

Yup exactly you want to use bar and you want to use pressures not molarity. Pressure equilibrium is different from concentration of molarity.

Keshav Patel 14B 2B

Amphiprotic is anything that can act as a Base or an acid by giving always or accepting electrons. Water does this in all reactions as when it’s bonded with an strong acid it creates acid or with a strong base it creates a base.

Keshav Patel 14B 2B

Ka and Kb will always = 1x 10^-14 which is the kW value. The reason why is because these two values are the concentrations of hydroniums and OH, which shows the basicity or acidity of the solution. When you do the log base of these values it gives you the pH. So it has to add up to 14.

Keshav Patel 14B 2B

Make sure all values are correct under the square root. Some may be negative but when multiplied with the C which should be a negative value you’ll get a positive X.

Keshav Patel 14B 2B

For the ice box method you have to look at the reactants and products. In most reactions you will see the reactants producing the products so the reactants will decrease. However in some cases if you’re working backwards you’ll have to subtract.

Keshav Patel 14B 2B

For the ideal gas law you want to use Kelvins because it often cancels with the R.

Keshav Patel 14B 2B

P standing for pressure should be in atm, V is the volume which should be in Liters. n is the moles of what you have, r is the constant that should be in ATM or just the same as whatever your P was. Finally T meaning temperature should be in Kelvins.

Keshav Patel 14B 2B

Use KP when you have anything to do with pressure. If you see any given partial pressure you want to use KP while KC is for varying molarity/ amount of the product/reactants you have.

Keshav Patel 14B 2B

Professor Lavelle said to use the atm for pressure. He said that it’s not too different and he prefers atm since it’s been around longer.

Keshav Patel 14B 2B

R is just the constant so you only use different R values dependent on the values that are in front of you. So if you have atm as one of the pressures you will use the R value with atm.

Keshav Patel 14B 2B

Water is amphoteric, it has the ability to act as an acid or base. Water acts as a base when mixed with acid and vice versa, this is a very important topic in acids in bases because often most acids/bases are mixed with water to truly understand their acidity or basicity.

Keshav Patel 14B 2B

The important difference between lewis and Bronsted is the definition. Lewis acid/base definition is based on the accepting or donating of pairs of electrons while Bronsted is based on the accepting and donating of a proton in the form of an H+ ion.

Keshav Patel 14B 2B

A ligand is anything that bonds to a coordinate covalent compound. Ligands always have a spare electron pair which allows them to bind and form a compound. Some ligands can be bidentate or tridentate meaning they have 2 electron pair donors or three.

Keshav Patel 14B 2B

Theres many different types of ways to define an acid and a base. A Lewis base and acid, the base being the one that donates electrons while the acid is the one accepting. By the Bronsted definition, the acids are the ones releasing an H+ and bases accepting an H+.

Keshav Patel 14B 2B

Anytime you have hydrogens and oxygens and you are determining strength of acid, always look at the number of oxygen. When you have more oxygen it stabilizes the structure much better with more oxygen than less after losing a hydrogen.

Keshav Patel 14B 2B

When you are trying to determine amphoteric compound in a reaction always look for where the hydrogen goes. If it leaves one compound then that one is the acid and the other is the base. Look at the reactants and the products to figure that out.

Keshav Patel 14B 2B

Amphoteric compounds are compounds that can act as either bases or acids depending on what elements are around them. Amphiprotic compounds can accept and donate hydrogens.

Keshav Patel 14B 2B

HF cannot be classified as a strong acid because fluorine has the highest electronegativity on the periodic table of element so it holds onto that hydrogen very tightly making it not a strong acid, but do not forget it is still an acid.

Keshav Patel 14B 2B

There is no negative PH. It can only range to the scale of 0-14.

Keshav Patel 14B 2B

When looking at the strength of acids always look at its ability to give off a hydrogen. When its a bigger a element it has longer bonds so it has a smaller bond on the hydrogens. But I see your point and yes stronger acids typically have a higher polarizability because it has more electrons and a l...

Keshav Patel 14B 2B

Most important part is to first read the question and understand what they are asking. They say to look at a phosphorous atom so it is not difficult at all. Locate one of them and find how many electron dense regions there are. Phosphorous in this diagram has 3 single bonds and one lone pair so it h...

Keshav Patel 14B 2B

When you're trying to find the hybridization orbitals just look for the amount of electron dense areas. C and O in that problem have 4 areas so you get sp3 because sp3 has 4 areas of electron density, S P P P being the 4 different orbitals that can have electrons.

Keshav Patel 14B 2B

Delocalized pi bonds always happen with resonance of atoms that have multiple bonds, typically double bonds. They are also in a circular pattern such as a hexagonal shape, so if you have a carbon chain with the same amount of hydrogen chances are you have delocalized pi bonds.

Keshav Patel 14B 2B

Hybridization is the explanation of what happens when you combine atoms to form a molecule. The bonds between atoms make hybridized orbitals because these atoms are being shared. There is no easy way to do it unless you practice and practice and you recognize molecules and their valence electrons by...

Keshav Patel 14B 2B

The 3 from the sp3 comes from the 3 atomic orbitals that p has. For example D has 5 orbitals and f has 7 as well as s having one. S does not have a number because the one is just one so its just S.

Keshav Patel 14B 2B

You got the answer correct because you chose the experimental value of the degrees when you have 2 lone pairs and 2 bonds. So both answers were acceptable.

Keshav Patel 14B 2B

Lone pairs are diffuse in the sense they repulse each other more than bonding pairs. That is why the lone pairs affect the shape of some molecules because they repulse the bonding pairs so much.

Keshav Patel 14B 2B

Since it has only bond its shape would be linear.

Keshav Patel 14B 2B

CH3F is tetrahedral, the fluorine however affects the bond angle. I am not sure how much it changes it.

Keshav Patel 14B 2B

You cannot determine bond angles from any molecular structure. You have to search it up because they are experimentally determined, but you can memorize them.

Keshav Patel 14B 2B

You can calculate it if you are given the table during a test. But you can always recognize ionic vs covalent by using the electronegativity trend. The most electronegativity is top right and the least being bottom left. So use this trend, and when elements are further away from each other you'll se...

Keshav Patel 14B 2B

CH4 exhibits LDF only because it is non polar. The reason why is because all the hydrogens have the same bond with the carbon and have the exact same pull. So there is induced dipole but there is nothing else.

Keshav Patel 14B 2B

The reason why resonance lowers energy is due to the double bond that there is. Because of a bond having resonance, all the bond lengths become shorter due to partial bond lengths. Basically, now all the bonds are shorter because of the resonance.

Keshav Patel 14B 2B

The easiest way to identify a radical is to first count the amount of valence electrons. Once you do this, anytime you have an odd amount of electrons, it is a radical. But often, they can be balanced you may have just forgot to add or subtract electrons according to the charge.

Keshav Patel 14B 2B

Beryllium will want to lose electrons and have 2 valence electrons. Beryllium is a cat anion and so to achieve a full outer shell, it will lose electrons from 2s2 to get to 1s2.

Keshav Patel 14B 2B

Sigma bonds are much stronger because when they overlap each other, they have a higher strength. While Pi bonds are side by side thus having less connection and much less strength.

Keshav Patel 14B 2B

Noble gases have a full valence electron shell, so they do not pair with anything unless electrons are forced onto it. Which requires quite a bit of energy and the electron is lost rapidly.

Keshav Patel 14B 2B

When you are doing a lewis dot structure for one independent atom, then you put the electrons according to the outer shell of valence electrons. The order is typically one dot clockwise at each spot until you use all of your electrons. Say you have 5 electrons in the other shell which would be nitro...

Keshav Patel 14B 2B

As people above have said, when you calculate the electronegativity, when it is above 2 it is a covalent bond and below 1.5 it is a ionic bond.

Keshav Patel 14B 2B

Due to the weaker connection of having 2 electrons in a single compared compared to a double bond with 4 electrons, the double bond is shorter because there are more protons in the double bond compared to the single bond.

Keshav Patel 14B 2B

Any time you have a question that either gives or asks for the indeterminacy for velocity or position, then you know you will be using the Heisenberg Equation.

Keshav Patel 14B 2B

S, P, D, and F are all subshells and within each sub shell you have an amount of orbitals. In S there is one orbital which has 2 electrons, P has 3 orbitals that can have 6 electrons, D has 5 orbitals which can have 10 electrons and finally f has 7 orbitals which can have a total of 14 electrons.

Keshav Patel 14B 2B

Wave lengths can have no discrepancies. They have to have a consistent amplitude and wavelength, if these differ then it will not be correct. Also it must start from the top and end at the bottom for it to count as a wavelength.

Keshav Patel 14B 2B

The Pauli Exclusion Principle states that orbitals can only have a maximum of 2 electrons per orbital and they almost must have opposing spins.

Keshav Patel 14B 2B

Always remember except for rare cases that electrons will always fill lower levels before they move onto higher levels. 4s is a higher energy level than 3d, hence the reason 3d fills first.

Keshav Patel 14B 2B

Mass of atoms should always be in Kilograms. When it comes to electrons, neutrons and protons all are on the formula sheet, so you will know the masses of all the following. So undoubtedly you will not get the mass of any of these particles in anything but kilograms.

Keshav Patel 14B 2B

Frequency is the amount of waves that are being sent in a period of time. Intensity is the light that can increase but the photons rendered in light can increase which is how intensity increases.

Keshav Patel 14B 2B

Planck's constant which is 6.626 times ten to the negative thirty fourth power has Joules. To cancel the joules, which is kilogram times m2 and s-2. This Kg needs to be removed to find the final frequency. You can only do this by having Kg at the denominator.

Keshav Patel 14B 2B

The purpose of the De Broglie equation is supposed to find the wave like function of small atoms. You can use momentum with Planck's constant to find the frequency of a small particle.

Keshav Patel 14B 2B

First things first remember when you're finding the molar mass from a mol you have to initially use avogadros number to convert to grams. Then from grams convert to kilograms!

Keshav Patel 14B 2B

Plancks constant which is 6.626 x 10 to the negative 34th power joules which is the electromagnetic radiation divided by frequency. This helps you find several other key parts of the Quantum World.

Keshav Patel 14B 2B

Meters is usually best, but nano meters works just as well for the final answer. You just have to make sure you're using scientific notation properly and you convert. Either works but more importantly focus on converting correctly.

Keshav Patel 14B 2B

Hello, once you have solved for the energy you have to find the longest wavelength of radiation which is the equation, I=hv. The I is the energy required to eject an electron, and the H being Planck's constant and V the wavelength.

Keshav Patel 14B 2B

Absolutely, work function and threshold energy are directly related. The work function is the amount of energy it takes to release an electron from a material, and the threshold energy is that amount of energy. Once the material passes that threshold of energy it immediately releases an electron.

Keshav Patel 14B 2B

Reading the textbook and taking notes. I write down all the formulas that are important and highlight them. I complete all the given homework assignments that were labeled in the textbook, and I follow answer that are also given and check my answers and the work behind it.

Keshav Patel 14B 2B

If you have 10.6 KG and you're converting to grams just move the decimal 3 places to the right because there are 1000grams in one KG. Its a simple way to do it.

Keshav Patel 14B 2B

When you are multiplying it is determined by the number with the least amount of significant digits.

Search found 104 matches