CHEMISTRY COMMUNITY

KimGiang2F

When converting units a problem relating to work of expansion given L•atm, are there certain conditions that would require us to use (101.325 J/ L•atm) and (8.314 J•K•mol^-1/ 0.08206 L•atm•K^-1*mol^-1)? Or can we just use any one of the conversion units?

KimGiang2F

After getting the skeletal equations for the oxidation and reduction half-reactions, you balance O atoms by adding H2O molecules. To balance the H atoms on each side add, for each H atom needed, one H2O molecule to the side of each equation that needs hydrogen and one OH- ion to the opposite side. F...

KimGiang2F

Even though a system is at equilibrium, the reaction does not stop. Instead, it continues just as fast in the direction from reactants to products (the forward direction), as it does from products to reactants (the reverse direction). The addition of a catalyst speeds up the forward and back reactio...

KimGiang2F

Yes, it would. The weaker the base, the smaller the value of Kb and the greater the value of pKb. Essentially, a large Kb value indicates the high level of dissociation of a strong base. A lower pKb value indicates a stronger base.

KimGiang2F

The text states that the rate law for a reaction is determined experimentally and cannot be inferred in general from the chemical equation of the reaction. So how can you determine the order of a reaction?

KimGiang2F

The number value 0.457 that you're referring to from the solutions is probably the initial rate for experiment 4, except the data gives the initial rate as 457 mol •L^-1•s^-1. In order to find the rate constant of the reaction, you have to take the initial rate and divide it by the product of the re...

KimGiang2F

After getting the skeletal equations for the oxidation and reduction half-reactions, you balance O atoms by adding H2O molecules. To balance the H atoms on each side add, for each H atom needed, one H2O molecule to the side of each equation that needs hydrogen and one OH- ion to the opposite side. F...

KimGiang2F

To get the reduction half-reaction for NO2-(aq) + Al(s) ----> NH3(g) + AlO2-(aq), first you get the skeletal equation (NO2-(aq) ----> NH3(g)). Then you balance O atoms by adding 2 H2O molecules. To balance the H atoms on each side add, for each H atom needed, one H2O molecule to the side of each equ...

KimGiang2F

The change in the system= the negative change of the surrounding in regards to reversible reactions is conceptually based on the fact that the amount lost and gained in both systems must be equal to 0. Essentially, if a system loses 10 units, the surrounding must gain 10 units so that the amount of ...

KimGiang2F

There is no direct relationship between entropy and enthalpy. Enthalpy (H) is the amount of energy released or absorbed during a chemical reaction while entropy (S), defines the degree of randomness or disorder in a system. However, the free energy (G) regroups both terms as G= H-TS, where at a cons...

KimGiang2F

At 0 K, NO has a greater residual entropy than BF3 because NO can be oriented as both NO and ON; BF3, no matter how you rotate the molecule, will look the same, because the F's are symmetric around the B. Therefore, NO has higher residual entropy, because it takes upon more orientations.

KimGiang2F

When the number of moles of gas is reduced, the standard residual entropy value is smaller than the standard molar entropy because residual entropy is the measure of how many different arrangements a molecule can have whereas, molar entropy is a measure of a molecule's chaos. With the moles of gas r...

KimGiang2F

Although adding a reactant increases the concentration of products at equilibrium, the increase in product concentration won't necessarily mean that the equilibrium product concentration becomes higher than that for the reactants. If K is bigger than one, the equilibrium concentration of the product...

KimGiang2F

The pKa gives you the acidity value of a substance and the Ka value indicates that the amount of acid that actually dissociates. While the pkb gives you the basicity value of a substance and the Kb value determines the level of dissociation of a base. For example, if given the pKa, you can use 10^-p...

KimGiang2F

Spectator ions are ions that are present in a solution but don't take part in a solution's chemical reaction. When reactants dissociate into ions, some of the ions may combine to form a new compound. Therefore, because they don't take on the role of an electron donator or acceptor, they will not aff...

KimGiang2F

If given the pKa, you can use 10^-pKA to get the Ka. Essentially to solve for the [H+] or x value, you set the Ka equal to [products]/[reactants]. To find the pH, you then take the -log of [H+]. The pKa gives you the acidity value of a substance and the Ka value indicates that the amount of acid tha...

KimGiang2F

If given the equilibrium constant, the higher the value, the higher a substance's solubility is. The equilibrium constant refers to the product of the concentration of the ions that are present in a saturated solution of an ionic compound, it is given the name solubility product constant. Therefore ...

KimGiang2F

When there is constant pressure and the reaction is irreversible, the equation w=-Pex∆V is derived from P=F/A, in which to find the force of the equation you can use the relationship and get F=PexA. The work needed to drive the piston out through a distance d is, therefore, work= PexA •d (work=force...

KimGiang2F

A reversible process is one that can be reversed by an infinitely small change in a variable. Whereas an irreversible process is an expansion against an external pressure that differs by a finite amount from the pressure of a system. To get a better understanding of a reversible change, you can cons...

KimGiang2F

An open system can exchange both matter and energy with the surroundings whereas a closed system has a fixed amount of matter but it can exchange energy with the surroundings. Examples of open systems can be automobiles or the human body. For the human body, we actively interact with our environment...

KimGiang2F

Sometimes when balancing the skeletal equation, one species may have oxygen on one side of the reaction and not the other. Essentially, you would need to add H2O to balance the O atoms and balance the H atoms by adding H+ where necessary.

KimGiang2F

To balance out a redox equation, first, start by identifying the species that is being reduced and oxidized from the changes in oxidation numbers. Then write the skeletal equations for the half-reactions and balance all elements except for H+ and O. You may notice that in the skeletal equation one s...

KimGiang2F

With the equation w=-Pex(∆V), the resulting unit is L•atm. 1 L•atm= 101.325 Joules. Essentially, you have to multiply your answer by 101.325 Joules in order to have the answer written in SI units.

KimGiang2F

An irreversible process is one by which the expansion against an external pressure differs by a finite (measurable) amount from the pressure of the system. Whereas, a reversible process is one that can be reversed by infinitesimal contributions within a variable. Even though the final volumes are th...

KimGiang2F

The equation w=-nRT(ln(V2/V1)), is the standard integral of the original equation, dw=-(nRT/V)dV. A reversible process is one that can be reversed by an infinitely small change (so small that the change is not measurable) in a variable. Therefore, the total work done within a process is the sum (int...

KimGiang2F

The standard way of reporting the values for enthalpy of vaporization is always reported as per one mole. Essentially you divide the heat by the number of moles, to get the enthalpy per mole.

KimGiang2F

In comparing the work of when a gas expands versus the work of isothermal expansion, I noticed a change carried out reversibly always does more work than a change carried out irreversibly but the values for the reversible process are technically lower. Why is it that the more negative the value, the...

KimGiang2F

In the problem 5G.9: "A sample of ozone, O3, amounting to 0.10 mol, is placed in a sealed container of volume 1.0 L and the reaction 2 O3(g) S 3 O2(g) is allowed to reach equilibrium. Then 0.50 mol O3 is placed in a second container of volume 1.0 L at the same temperature and allowed to reach e...

KimGiang2F

Normally, when the concentration of the products isn't given for equilibrium problems and only reactants are presented initially, it is assumed products have very low concentrations that would make solving the problems to be more complex. Essentially, to make calculations easier and less complicated...

KimGiang2F

In reaction presented, N2(g) + 3H2(g) -> 2 NH3(g) at 400, K = 41. The reaction of part B, 1/2 N2(g) + 3/2 H2(g) ->NH3(g), changed in the amount of moles. However, the ratio of the moles of the equation of part B is proportional to the ratio of the moles of the equation of part A by one-half. We assu...

KimGiang2F

I think that you have to start by looking at the equation for the equilibrium constant, K, of the problem presented. Notice that if you were to write out the expression for the reaction, you would get K=[O2]^3/[O3]^2. Essentially, you would also get the ratio: [O2]^3/[O3]^2. Now we know that the equ...

CHEMISTRY COMMUNITY

Search found 31 matches

Conversion Units for Work Expansion

Re: redox in basic solutions

Re: Le Chatlier Principle

Re: What is pKa and Ka exactly?

Order of reaction

Re: Problem 7A17

Re: Balancing redox rxns in basic solution

Re: Basic solution reaction

Re: System and surroundings

Re: entropy and enthalpy

Re: Residual Entropy

Re: Entropy and Reduction in moles of Gas

Re: Initial Concentration and Equilibrium Concentration

Re: pKa and pKb

Re: Salt Solution

Re: Acid Base

Re: Equilibrium Constants and Solubility

Re: Reversible vs irreversible

Re: reversible and irreversible processes

Re: Closed vs Isolated

Re: Balancing / Skeletal Equations

Re: HW help

Re: 4B.13a

Re: Irreversible and reversible expansion, 6th edition 8.11

Re: 4B.13b

Re: Help on 8.37a.

Work

5G.9 Moles and Partial Pressure in Equilibrium

Re: ICE Table

Re: 5H.1 part B

Re: Number 5G.9 Question