CHEMISTRY COMMUNITY

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In problems, where they give us a slow and fast reaction, how do you determine which variable is a catalyst and which is a intermediate step?

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From a UA, all step up sessions may be cancelled because they are leaving campus as well.

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For part D, it asks for us to predict the initial rate for experiment 5. I have already found the rate law and got a value for the reaction rate constant. Are we supposed to just plug everything in from experiment 5? Can someone explain the steps on how to solve part d?

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Can someone explain how to do this problem. How does the factor of 1.2 affect the equation? 7A.13 In the reaction CH3Br(aq)1OH2(aq)SCH3OH(aq)1 Br2(aq), when the OH2 concentration alone was doubled, the rate doubled; when the CH3Br concentration alone was increased by a factor of 1.2, the rate increa...

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Can someone explain the difference between initial reaction rate and reaction rate?

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Can someone explain the concept of unique rate and rate law. How are they different?

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How do you determine which values to use from the list of experiments when trying to find the order reaction?

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How do you calculate the overall order?

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how is a second order reaction related to a 2nd order integrated law?
Can someone explain each concept separately and how they are interconnected.

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I'm still not understanding this concept. Can someone explain the concept of the difference between a first order reaction and a second order reaction?

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6M.7 Arrange the following metals in order of increasing strength as reducing agents for species in aqueous solution: (a) Cu, Zn, Cr, Fe; (b) Li, Na, K, Mg; (c) U, V, Ti, Al; (d) Ni, Sn, Au, Ag. how can you determine which has a low reduction potential? In this problem, are there specific values to ...

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Can someone explainhow to do 6M.5 part b. The solution manual just says not spontaneous, but I got a value for a spontaneous reaction.

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6M.1 A student was given a standard Cu(s)/Cu21(aq) half-cell and another half-cell containing an unknown metal M in 1.00 m M(NO3)2(aq) and formed the cell M(s)|M1(aq)|Cu21(aq)|Cu(s). The cell potential was found to be 20.689 V. What is the value of Energy potenial (M21/M)? In this problem, why are w...

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In a galvanic cell, how do you determine what is the reactant/product in an equation for anode/cathode ?
(e) Pt(s)|Sn41(aq),Sn2(aq)||Cl-(aq)|Hg2Cl2(s)|Hg(l)

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(b) C(gr) |H2(g)|H+(aq)||7Cl2(aq)|Cl2(g
In this problem why is Cl2 the reactant in the reduction rxn?

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Do you you have to consider the coefficient when determining the overall charge of the molecule?

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In class they told us to not consider water as an active part in the reaction, so in this question would we consider water?
(d) Reaction of chlorine in water: Cl2(g) =HClO(aq) + Cl2(g)

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is 3I- to I3- a oxidation or reduction ? Can you explain why as well.

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i get confused on how to figure out which one is being reduced and oxidized in redox rxns. Does anyone know how I can tell the difference for example MnO4^- to Mn^2+. Since it is going from a negative to positive charge in the end wouldn't it mean that it is being oxidized?

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After what step do you have to add in OH- to balance your redox equation? Is it after you add H20 or after adding your protons?

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why does the element oxygen have a -2 charge but oxygen by itself in a molecule has a charge of zero?

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I'm still having trouble understand what an anode and cathode is.
Can someone explain what these two things are and when they are applied in electrochemistry?

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Can someone explain why the total entropy value is zero in a reversible isothermal system? Similarly why is the entropy value 0 for the surroundings in an irreversible isothermal system?

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Which equations do you tend to use when solving for an isobaric system?
Also which values are equal to zero in an isobaric system?

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Can someone tell me what values such as heat, pressure, etc are equals to zero in an ideal gas of an isothermal reversible system?

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I am confused as well especially when utilizing the equation W=-nRT sometimes the solution is positive work instead of negative. How can I tell if it’s negative or positive even if the equation has a negative sign in it?

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In this problem, I have alread found the kj/mol but where do I bring in the density value so solve for the enthalpy density? 4D.9 The enthalpy of formation of trinitrotoluene (TNT) is 267 kJ?mol21, and the density of TNT is 1.65 g?cm23. In principle, it could be used as a rocket fuel, with the gases...

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for expansion do you need to include a negative sign when calculating values
what about compression?

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What equation(s) should be utilized to find the internal energy? I have a feeling q=mcdeltat will be used. The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise f...

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Can someone give a general list of common elements/compounds we will be using that have a bond enthalpy value of zero?

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I'm having trouble understanding the differences between these:
Can someone explain the concepts of:
1) bond enthalpy
2) standard enthalpy of formation
3) standard reaction enthalpy

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I'm having trouble understanding the concept of state function? How does it apply to enthalpy?

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I don't understand what a calorimeter is. Can someone explain what it is used for and when it should be applied?

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can someone explain hess's law? and when it is applied?

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in the last example given during lecture can someone explain how they got the mass of the solution when calculating enthalpy?

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is enthalpy an intensive or extensive property?

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Can someone explain how pressure affects equilibrium?

State whether reactants or products will be favored by an increase in the total pressure (resulting from compression) on each of the following equilibria. If there is no change, explain why that is so.

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how does expansion affect a reaction and because of it which is more favored products or reactants?

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Why do noble gases neither affect the reactants or products in an equilibrium equation?

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What is the difference between K and Kc? Can they be used interchangeably?

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For the reaction H2(g) 1 I2(g) ∆ 2 HI(g), K 5 160. at 500. K. An analysis of a reaction mixture at 500. K showed that it had the composition PH2 5 0.20 bar, P I2 5 0.10 bar, and PHI 5 0.10 bar. (a) Calculate the reaction quotient. (b) Is the reaction mixture at equilibrium? (c) If not, is there a te...

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A reaction vessel of volume 0.500 L at 700. K contains 1.20 mmol SO2(g), 0.50 mmol O2(g), and 0.10 mmol SO3(g). At 700. K, Kc 5 1.7 3 106 for the equilibrium 2 SO2(g) 1 O2(g) ∆ 2 SO3(g). (a) Calculate the reaction quotient Qc. For part a i keep getting the wrong answer can someone show me how to app...

aphung1E

For test 1, will we have to write the equations for acids and bases to find their pH? Is there a certain trick to tell whether you need to se use H30+ or OH- in your equation? Can someone explain how to think logically to write an equation for a solid/base?

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What should be covered in terms of acids and bases in preparation for test 1?

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Can someone explain how to do part b of the proble step by step as well as part c. 5G.5 The following flasks show the dissociation of a diatomic molecule, X2, over time. (a) Which flask represents the point in time at which the reaction has reached equilibrium? (b) What percentage of the X2 molecule...

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(d) If the Gibbs free energy is greater than the standard Gibbs free energy of reaction, the reaction proceeds forward to equilibrium.
Can someone explain how to solve this problem? Can you also explain what Gibbs free energy is?

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Can someone explain dynamic equilibrium?

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For a heterogeneous equilibrium, what expression is utilized to find the equilibrium constant?

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True or False: the equilibrium concentrations will be the same whether one starts wit pure reactants or pure products.

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Does the equation to find the equilibrium constant only apply to ideal gases or can it be used as well when there are phase changes?

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Below are molecular models of two oxoacids. Write the
name of each acid and then draw the model of its conjugate base.
(Red 5 O, white 5 H, green 5 Cl, and blue 5 N.) Does it matter the format your write the molecular formula?

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Can someone clarify the difference between bronsted acids and bases and conjugate acids and bases?

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how is bronsted acids and bases connected to lewis acids and bases? what makes acid a lewis acid and vise versa with a bronsted acid?

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For problem 6A.11 part A how do they get the product (h30)+ + (co3)^2- ?

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For problem 6a.13, is there any way to tell whether a molecule is an acid or base?

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How can you tell if a ligand is polydentate?

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what does edta and en represent in a coordination compound

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With the help of Table 9C.1, determine the coordination
number of the metal ion in each of the following complexes:
1; (c) [PtCl2(en)2]2+
21; (d) [Cr(edta)]-
can soomeone explain step by step how to do this problem.

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can someone explain step by step how to find coordination number of sodium dichloridobis(oxalato)platinate(IV).

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Name each of the following complex ions and identify the
oxidation number of the metal: (c) [Co(CN)5(OH2)]^2-

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Name each of the following complex ions and identify the
oxidation number of the metal: (a) [Fe(CN)6]

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Can someone explain conceptually what coordination compounds are

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how do lone pairs around a central atom affect the bond angles in a cation/anion?

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how do lone pairs around a central atom affect the bond angles in a molecule?

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why are lone pairs more likely to be found in certain locations around a central atom?

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Can someone explain how to find which has highest to lowest boiling point: H2S, H2O, KCl, KI

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I though BH2 would be polar, but apparently it is nonpolar. Can someone explain why BH2 is nonpolar?

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Can someone explain what VSEPR does or what information it tells us?

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Can someone explain what are ion-ion, ion-dipole, dipole-dipole, dipole-induced dipole, and induced-induced dipole is?

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Can someone explain how to use dipole moments to figure out if a molecule is polar or not?

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Can someone explain how to solve this?

Arrange the anions Cl 2 , Br 2 , N 32 , and O 22 in order of
increasing polarizability and give reasons for your decisions.

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What is the difference between polarizing power and polarizability?

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How do you determine if a compound is polar or not?

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I need help solving this problem. Please explain step by step.

Arrange the anions Cl^-, Br^-, N^3-, O^2- in order of increasing polarizability ad give reasons for your decisions.

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I'm still not understanding the concept of dipole moment too well. Can someone explain how this applies in lewis structures?

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Is it better for the central atom to have a +/- charge or have the other atoms take the +/- charge? And if so, why?

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Is it true that elements located in period 3 specifically elements Al-Ar are an exception to the octet rule? And if so why?

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When drawing regular lewis structures do you always have to draw them where their formal charges are zero?

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How do you solve this ? Is there a certain rule you have to follow?
2A.15 Write the most likely charge for the ions formed by each of
the following elements: (a) S; (b) Te; (c) Rb; (d) Ga; (e) Cd.

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Can someone show step by step how to do this problem?
2A.13 For each of the following ground-state atoms, predict the
type of orbital (1s, 2p, 3d, 4f, etc.) from which an electron will need
to be removed to form the 1 1 ions: (a) Zn; (b) Cl; (c) Al; (d) Cu

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Can someone clear up what resonance is because what I'm grasping from this topic is that its an electron that can be in different arrangements.

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While trying to find the formal charge, how do you find the shared electrons?

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Can someone explain how to find the lone pair electrons when trying to find the formal charge?

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If the element is past the second period in the periodic table does it still need to follow the octet rule?

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How do you determine how many valence electrons an element has using the periodic table?

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How do you determine which element is less electronegative in a compound element?

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Does Hund's rule apply to the Pauli Exclusion Principle?

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Does the ionization energy increase/decrease down a group in the periodic table?

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How do you know if an electron will spin up or spin down? It depends on the values for n,l,m, right?

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Do n,l, m always follow a certain patter or does it vary?
ex: n=1, l=0, m=0 < will it always follow this pattern?

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Can someone explain what subshells are and how they relate to the orbital?

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How do you determine which are the valence electrons after you write out your electron configuration?

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For this problem, do I need to find the mole of sodium?

1B.7 Sodium vapor lamps, used for public lighting, emit yellow
light of wavelength 589 nm. How much energy is emitted by (a) an
excited sodium atom when it generates a photon;

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For part a what equation can be used to solve for wavelength? The velocity of an electron that is emitted from a metallic surface by a photon is 3.6x10^3 kms (a) What is the wavelength of the ejected electron? (b) No electrons are emitted from the surface of the metal until the frequency of the radi...

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1A.9 A college student recently had a busy day. Each of the student’s activities on that day (reading, getting a dental x-ray, making popcorn in a microwave oven, and acquiring a suntan) involved radiation from a different part of the electromagnetic spectrum. Complete the following table and match ...

aphung1E

Does anyone know the energy of microwaves?

Arrange the following types of photons of electromagnetic
radiation in order of increasing energy: g -rays, visible light, ultraviolet radiation, microwaves, x-rays.

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What conversion would we use to turn the value into picometers? 1A.7 (a) The frequency of violet light is 7.1 3 10 14 Hz. What is the wavelength (in nanometers) of violet light? (b) When an electron beam strikes a block of copper, x-rays with a frequency of 2.0 3 10 18 Hz are emitted. What is the wa...

aphung1E

What equation should be utilized for this problem?

1A.15 In the ultraviolet spectrum of atomic hydrogen, a line is
observed at 102.6 nm. Determine the values of n for the initial and
final energy levels of the electron during the emission of energy
that leads to this spectral line.

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Can someone clarify the answer? Which of the following statements about the electromagnetic spectrum is true? Explain your reasoning. (a) X-rays travel faster than infrared radiation because they have higher energy. (b) The wavelength of visible radiation decreases as its color changes from blue to ...

aphung1E

A) to turn moles into formula units/atoms i used the equation from the textbook Number of object=amount in moles x avagadro's constant so you multiply 0.750 mol KNO3 x (6.022x10^23) and get 4.52x10^23 formula units. B) They're asking us for the mass so we will need to find the moles. With the formul...

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