CHEMISTRY COMMUNITY

505306205

The half-life for a first order reaction is used because it remains constant for a substance and is independent of reactant concentration.

505306205

A zero order reaction would be an enzymatic reaction in which the enzyme is saturated so the reaction rate does not increase even if the concentration of the reactants increases.

505306205

If an enzyme is saturated, then the reaction rate is not going to increase even if the concentration of reactant increases.

505306205

An intermediate species is a species that is formed in the middle of the reaction but does not appear in the overall reaction equation or overall reaction rate equation.

505306205

A first order reaction is one that is a straight line on the ln[a] vs time graph. A second order reaction is one that is a straight line on the 1/[a] vs time graph.

505306205

For a galvanic cell, the oxidation is on the left and the reduction is on the right.

505306205

Will section 6O be on the test because it covers some concepts we didn't go over in class?

505306205

This is because in the equation, deltaG = -nFE, the n compensates for the change in the molar quantities so E has to remain the same for deltaG to change.

505306205

An anode is the site of oxidation and cathode is the site of reduction.

505306205

Yes. Typically, you write the oxidation (anode) on the left and the reduction(cathode) on the right.

505306205

A first order reaction is characterized by the linear graph of concentration and time.

505306205

If the question is asking you to find an unknown concentration in the cell diagram, then I would write it as part of it.

505306205

At the anode, the electrons leave the electrode and migrate to the cathode. Thus, the anode is oxidized while the cathode is reduced.

505306205

The half-reactions represent the oxidation and reduction reactions. For a species to be reduced, it has to accept electrons from a species that has to be oxidized.

505306205

Maximum voltage occurs right when the switch is closed, which is when there is least current flowing.

505306205

The salt bridge allows the charge to be balanced on both sides, therefore it allows the charge to continue transferring.

505306205

A battery goes dead when the reaction inside has reached equilibrium ( the transfer of net charge has stopped).

505306205

Reduced species are those that gain electrons and oxidized species are those that lose electrons.

505306205

The maximum voltage occurs just when the switch is closed. This is because voltage is equal to J/Coulomb of charge and since charge is in the denominator, maximum voltage occurs at the least charge.

505306205

Adding an inert gas does not shift the reaction because it doesn't react with any of the reactants or products so the concentrations of each don't change.

505306205

The second one is gibbs free energy measured under standard conditions. This gibbs free energy remains constant throughout the reaction .

505306205

The anode is always oxidized and the cathode is always reduced, so the electron will always travel from the anode to the cathode.

505306205

This is in a bomb calorimeter so volume is constant, so no work is done. delta U is equal to q, which is C(deltaT). C is the capacity of the bomb calorimeter and T is the temperature change given.

505306205

An open system is always constant pressure because the system is exposed to the air which is at constant pressure.

505306205

a reaction is spontaneous if the total entropy is positive

505306205

a reaction is spontaneous if the total entropy is positive

505306205

The acronym is P D TV HUGS. When your under pressure and depressed, you should watch TV and gets hugs. P = Pressure, D = density, T = temperature, V = volume, H = enthalpy, U = internal E, G = gibbs free energy, and S = entropy. Heat capacity is also a state function.

505306205

When a reaction has reached equilibrium, the rate at which products are formed is equal to the rate at which reactants are formed. The concentrations of reactants and products remain constant.

505306205

In a reaction, you have both the breaking of bonds and forming of bonds. Therefore, there are energy requirements and energy release involved in a reaction. Just depends on whether the requirement out-weights the release or not.

505306205

delta H is the heat measured under constant pressure.

505306205

If Ka is less than 10-3, then it is a weak acid. Greater than 10^3 would make it a strong acid.

505306205

Heat capacity is an extensive property while specific heat capacity is an intensive property. Intensive properties are more important to us.

505306205

The stirrer also helps to homogenize the solution so that the change in temperature is distributed evenly.

505306205

Enthalpy is an extensive property. Another extensive property is heat capacity. Specific heat capacity, however, is an intensive property.

505306205

A calorimeter is an instrument used to calculate the change in Temperature caused by a reaction and using this change to calculate the enthalpy of reaction.

505306205

The enthalpy of sublimation is simply the sum of the heat of fusion and the heat of vaporization.

505306205

Q value is calculated when you don't know whether the reaction is at equilibrium or not. If Q equals K, then the reaction is at equilibrium.

505306205

An exothermic reaction will have a delta H value that is negative and an endothermic reaction will have a delta H value that is positive.

505306205

A buffer is a solution that contains both conjugates. In the ICE table, therefore, the starting concentration for the conjugate acid/base is not 0.

505306205

Yes, H20 is included in the K equation when it is a gas.

505306205

Because ATP hydrolysis is exergonic, so the products have less energy than the reactants. Thus, the products are more stable than the reactants.

505306205

You eliminate x from the denominator when K is less than 0.001. This is because when K is this small, the change (x) will be less than 5% of the initial concentration.

505306205

Q is greater than K when there more products than the equilibrium concentration of products.

505306205

Calculating Q is the same as calculating K.

505306205

If stress is put on a system, then the reaction shifts in the direction that minimizes that stress.

505306205

K and Q are different because K represents the reaction at equilibrium whereas Q represents the reaction at a point other than at equilibrium.

505306205

Solids are not used because you cannot measure the concentration of solids. Liquids are not used because pure liquids are too dilute to affect the K.

505306205

A weak base will not raise the pH as much as a strong base would and that also goes for weak acids as they are incompletely protonated/deprotonized.

505306205

Bond angles will be less than the ideal structure due to lone pair and bond pair repulsion and/or lone-pair lone-pair repulsions.

505306205

Dirty coal has more Sulfur in it while clean coal has less sulfur content and thus more Carbon content.

505306205

Cis can form two bonds because the Chlorines are on the same side, while in trans they are opposite of each other.

505306205

I don't think we need to know its impact on the environment. We just need to know the chemical equations associated with it and that the primary acid in acid rain is carbonic acid.

505306205

Relative strength of an acid can be calculated using the Ka value of the acid, assuming the acid is a weak acid. Ka = [H+][A-]/[HA]. The higher the Ka value, the stronger the acid.

505306205

[OH-][H+] = 1x10^14, which is equal to Kw. If we take the -log of each side, we get pOH + pH = 14. Knowing the pOH will allow you to calculate the pH of the solution.

505306205

It is more accurate to use H3O+ in place of H+ because the acid will donate its proton to the water molecule to form H3O+. Calculating pH is the same if you take H3O+ in place of H+.

505306205

In binary acids H-A, the greater the electron affinity and thus the electronegativity of the A element, the more polarizing the molecule and thus, the Hydrogen is more easily lost to a proton acceptor and thus, its Ka value will be greater and pKa will be smaller compared to that of a binary acid in...

505306205

Lewis acids accept electron pairs and Lewis bases donate electron pairs while Bronsted acids donate protons and Bronsted bases accept protons. Lewis acids includes the proton while Bronsted only considers compounds as acidic if they supply protons.

505306205

Acid and Base classification differs depending on whether you are discussing Arrhenius, Bronsted, or Lewis acids and bases. Arrhenius acids form H+ ions in water, while bases form OH- ions in water. Bronsted acids donate protons while Bronsted bases accept protons. Lewis acids accept electron pairs ...

505306205

All single bonds are sigma bonds. In double or triple bonds, there is one sigma bond and the rest are pi.

505306205

If a bond order is zero, that means that the molecule is too unstable and it will not exist.

505306205

cis indicates that the functional groups are on the same side of the carbon chain while trans conveys that functional groups are on opposing sides of the carbon chain

505306205

If the atoms bonded to the central atom are not the same, the size and electron distribution around the atoms will differ which will affect the distribution of the electrons on the other atoms, which will affect the bond angle.

505306205

A lone pair is a potential site for hydrogen bonding. Hydrogen bonding can also be possible when hydrogen is near a nitrogen, oxygen, or fluorine atom.

505306205

Lone pair - lone pair repulsion is stronger than lone-pair bond pair which is stronger than bond pair-bond pair, regardless of whether it involves a cation, anion, or molecule.

505306205

You should memorize the different orientations and their bond angles as it will be useful for the upcoming test.

505306205

Boiling point increases when the strength of the intermolecular force increases. For instance, molecules that have induced-dipole attraction have a lower boiling point that molecules that interact through ionic interactions.

505306205

A non-covalent interaction is different from covalent because it does not involve the sharing of electrons, but instead has more dispersed variations of electromagnetic interactions between or within molecules.

505306205

induced dipole-dipole are not permanent forces. They are temporary dipoles that have been induced by a neighboring molecule. Also, most intermolecular forces are not permanent.

505306205

Two sigma bonds are not possible because the orbitals overlap end-to-end in a sigma bond. In order to form another bond to share more electrons, it is only possible for their orbitals to overlap side-to-side to form a pi bond.

505306205

Pi bonds are weaker than sigma bonds because the of the parallel orbital paths which mean less overlap between the p-orbitals. Pi bonds happen when two atomic orbitals are in contact through two areas of overlap. Pi bonds are also more spread out than sigma bonds.

505306205

When aqueous environment, covalent bond are stronger than ionic bonds because compounds held together by ionic bonds tend to dissolve in water and dissociate into the individual ions whereas the molecules in molecular compounds do not break up when in water.

505306205

The lone pairs are delocalized whereas the electrons in a bond are not free to move as much. Therefore, the repulsions between the electrons in lone pairs can distort the electron cloud.

505306205

Nitrogen also has a lower IE because it has half-filled p subshell which is more stable than the 4 electron configuration in the p orbital of oxygen.

505306205

In a many electron system, the orbitals within a shell differ in their energies. This difference is attributed to electron-electron repulsions within the orbitals. This is different from a one electron system, in which the orbitals within a shell are degenerate (are of the same energies).

505306205

Electrons have wave-particle duality. Schrodinger equation is used to represent the wave-like characteristic of electrons. The square of the wave function represents the probability density of finding an electron in a particular space.

505306205

Usually you can tell if you need the incomplete octet when the number of total electrons doesn't equal the total number of electrons in the structure and you cant accommodate with more bonds.

505306205

What is the trend of electronegativity in terms of the periodic table? Does electronegativity increase as you go towards the right of the periodic table? The trend for electronegativity is that it increases diagonally from bottom left to the top right. Flourine, therefore, is the most electronegati...

505306205

Formal charge is calculated by subtracting the number of bonds plus the number of free electrons from the number of valence electrons of that atom. The sum of the number of bonds plus the number of free electrons can be thought of as the sum of the number of sticks (bonds) and dots (electrons).

505306205

Electron spins affect an electron's behavior because it prevents two electrons with parallel spins from occupying the same orbital. The configuration is most stable when electrons are paired with electrons with opposite spins.

505306205

The atomic radius is measured by halving the inter-nuclear distance between two like atoms. This is what the Angstrom represents.

505306205

The arrangement that allows for the lowest formal charge is the one that matches closest to the true structure. Also, it is important to remember that the atom with the lower electron affinity should not get the most negative formal charge.

505306205

Can someone explain how to set this up so that you can get to the electron configuration. I understand that you want to fill the shells so that they become more stable and how to put in the spin state but what is the order that you fill in the shells? You fill the shells in order of increasing ener...

505306205

Aprice_1J wrote:When would you see them have parallel spins? If they are more stable with different spins, what would constitute them having the same spin?

Electrons with the same spin cannot occupy the same orbital. Electrons singly occupy the different orbitals with parallel spins (Hund's Rule).

505306205

The difference in spin only shows up in the presence of a magnetic field. In the absence of magnetic field, the electron spins have the same energy, however, this is not the case when the atom beam of silver ions passed through a magnetic field in the experiment.

505306205

If a wave equation represents electrons, a change in the wave function will give the energy associated with the wave function. The double derivative of the wave function allows us to return to the original equation. For example, when we take the derivative of sinx, we get cosx, and when we take the ...

505306205

If electrons only acted as particles, there would be no diffraction pattern. The electrons would have been detected in one spot as opposed to more than one.

505306205

The number of orbitals are usually found using the magnetic quantum number, m subscript l. For example, the quantum number l = 1 would have ml equal to -1, 0, 1 which corresponds to 3 p orbitals. The p is found based on the value of l. A value of 0 corresponds to s orbital, 1 to p orbital, 2 to d or...

505306205

It applies to one electron systems only because for one electron systems, the different energy levels are degenerate, or equal in energy. However, for multi-electron systems, this is not true.

505306205

The wavelength of light is different from the wavelength of a photon/electron. The equation for light is c = wavelength x frequency, whereas, the equation for wavelength of an electron is wavelength = h (Planck's constant)/p (momentum).

505306205

Black body refers to anything that absorbs all forms of electromagnetic radiation, regardless of frequency.

505306205

The example relates to quanta because in the quantum world, energy is assumed to be in quantized, or discreet amounts rather than being continuous. On the surface, the water from the bucket looks like it is flowing in one continuous motion. However, when you are on the molecular level, water is comi...

505306205

When an electron moves from a higher energy level to a lower energy level, it emits or releases energy. The release of energy is associated with a more stable state. Transitioning from n=4 to n=2 allows the electron to achieve a more stable state, and thus, it emits energy.

505306205

It is also important to remember that equations for electromagnetic radiation (waves) cannot be directly applied to equations for measuring wavelength associated with an electron. For example, the equation: c = lamda x frequency cannot be used to solve for the electron's wavelength. There is a separ...

505306205

There's a list of strong acids and bases in the textbook which would come in handy for some of the problems, so I suggest memorizing them. Learning these would also help with understanding the nomenclature pattern of acids/bases and the ions involved.

505306205

Try to avoid rounding until the very end when you have to give the answer with the correct number of significant figures, which is the least number of significant figures among the numbers given in the question.

505306205

To find the limiting reactant, I find it helpful to calculate the number of moles of other reactants required for each reactant and then comparing that value to the number of moles that actually exist for each reactant.

505306205

Chemical equations can be divided up into combination, decomposition, single displacement, double displacement, combustion, and redox reactions. Combination involves two or more reactants that form one product and decomposition is the reverse of that. In single displacement, the more active element ...

Search found 97 matches