CHEMISTRY COMMUNITY

Emma Scholes 1L

What does the frequency factor mean?

Emma Scholes 1L

Yes. The half life equation depends on the reaction order.

Emma Scholes 1L

What is an example of a zero order reaction?

Emma Scholes 1L

In a zero order reaction, the rate of the reaction does not depend on the concentration of the reactant.

Emma Scholes 1L

The graph for the second order looks like a line with a positive slope.

Emma Scholes 1L

What is the difference between E cell and E^o ?

Emma Scholes 1L

The equation for the anode part of the reaction is Fe^2+(aq)--> Fe^3+(aq) +1e-
Why does Fe^3+ come before Fe^2+ in the cell diagram?
Pt(s)I Fe^3+(aq), Fe^2+(aq)II

Emma Scholes 1L

K varies by temperature, so the Van Hoff equation is used to calculate K at a different temperature. If you know delta H and the K value at one temperature, you can use the equation to find K at a different temperature.

Emma Scholes 1L

You can find the values in Appendix 2B.

Emma Scholes 1L

Voltage can be negative, but if it is negative the battery will not work.

Emma Scholes 1L

You can solve an equilibrium problem without using an approximation. Approximations act like a short cut. If the questions stated to not use an approximation, you would do the problem using the quadratic formula.

Emma Scholes 1L

What is the purpose of the salt bridge?

Emma Scholes 1L

You know Fe lost 5 electrons because originally there are 5 Fe 2+ which has a total charge of 10+. After the reaction there is 5 Fe 3+ which has a total charge of 15+. In order to go from 10+ to 15+, 5 electrons must be lost.

Emma Scholes 1L

What does an ideal gas mean?

Emma Scholes 1L

Delta H is equal to q when there is constant pressure.

Emma Scholes 1L

You can use either J or kJ. Both will be accepted on the test, but when the amount of J is above 1000, it is usually written in kJ.

Emma Scholes 1L

U is a state property because the value is determined by its current state. A state property is not dependent on the path taken to obtain that state.

Emma Scholes 1L

Degeneracy is the number of ways of achieving a given energy state.

Emma Scholes 1L

q is the heat exchanged between the system and its surroundings.

Emma Scholes 1L

The solution manual says that in part a) Tf= 343K and in part b) Tf= 373K.

Emma Scholes 1L

What is the purpose of a calorimeter and how does it work?

Emma Scholes 1L

When finding the standard enthalpy of an equation, how can you make sure that everything is in standard state?

Emma Scholes 1L

Use an ICE chart and find the concentration of H30+ by using the given pH.

Emma Scholes 1L

What is the difference between an endothermic reaction and an exothermic reaction?

Emma Scholes 1L

It is the same rule for pKa because the rule applies whenever you take the log of something.

Emma Scholes 1L

If we increase N2 the reaction will proceed to the right so more product is formed.
If we increase NH3 the reaction will proceed to the left so more reactants are formed.
If we decrease H2 the reaction will proceed to the left so more reactants are formed.

Emma Scholes 1L

How can you tell what is a weak acid vs. what is a strong acid?

Emma Scholes 1L

K is used to describe a reaction that is at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If Q is equal to K, the reaction is at equilibrium.

Emma Scholes 1L

The Reaction Quotient is calculated the same way that K is calculated. The equation is Q=[Products]/[Reactants]. The reaction quotient is used to determine which direction the reaction will proceed.

Emma Scholes 1L

K is used to describe a reaction at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If the reaction quotient is equal to K, you know that the reaction is at equilibrium.

Emma Scholes 1L

How do we know when to write the equation for Kc vs. Kp when the question just asks to find the expression for K like in question 5G3?

Emma Scholes 1L

The formula of the conjugate acid is CH3NH3+. You just add an H+.

Emma Scholes 1L

How can you determine the name of an acid?

Emma Scholes 1L

How can you tell if a compound is aqueous?

Emma Scholes 1L

The hybridization of CH2 and CH are sp2 because there are only three areas of electron density surrounding them. The C in CH2 has one bond connecting each of the two hydrogens and a double bond connecting it to the other carbon. The C in CH has one bond connecting it to the hydrogen, one double bond...

Emma Scholes 1L

You know the order because triple bonds are shorter than double bonds, and double bonds are shorter than single bonds.

Emma Scholes 1L

You can write it either way. Both are considered correct.

Emma Scholes 1L

The atom with the smallest electronegativity is typically the central atom because atoms with high electronegativity are more reluctant to share their electrons with other atoms and instead keep their lone pairs.

Emma Scholes 1L

What are the bond angles of a seesaw?

Emma Scholes 1L

Is having a molecular shape that is bent the same as having a molecular shape that is angular?

Emma Scholes 1L

How does the molecular shape affect the boiling point?

Emma Scholes 1L

Do all molecules have Van der Waals forces?

Emma Scholes 1L

A rough guideline to determine if something is an ionic bond is to use electronegativity. If the electronegativity difference is greater than 2, it is likely an ionic bond. BaBr2 is more ionic than BeBr2 and BBr3 because the electronegativity difference is greater.

Emma Scholes 1L

How can you tell the polarizability of a molecule?

Emma Scholes 1L

What is interaction potential energy? Why is it always negative?

Emma Scholes 1L

Any atom that is in the third period or below can have an expanded octet.

Emma Scholes 1L

What is a coordinate covalent bond? How does it relate to octet exceptions?

Emma Scholes 1L

Why are double bonds shorter than single bonds?

Emma Scholes 1L

What is the difference between electron affinity and electronegativity?

Emma Scholes 1L

I think he updated the test and exam schedule because now it says Test 3 starts Tuesday November 27.

Emma Scholes 1L

Can anyone explain how to do number 7 on the Quantum World Worksheet 2 the way Professor Lavelle showed us in class? Here is the question. An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level for which n=4. In what principle quantum level did the electro...

Emma Scholes 1L

There are always 3 nodal planes for f orbitals.

Emma Scholes 1L

How can you tell which orbitals have nodal planes?

Emma Scholes 1L

Question 1D 13 part d asks how many subshells are there in the shell with n=4. In this case there would be four subshells (4s, 4p, 4d, and 4f).

Emma Scholes 1L

I think it will be given.

Emma Scholes 1L

The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86. What is the wavelength of this krypton-86 radiation?

Emma Scholes 1L

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

Emma Scholes 1L

A lamp rated at 32. W (1W=1J/s) emits violet light of wavelength 420nm. How many moles of photons are emitted in 2.0 seconds?

Emma Scholes 1L

Sodium vapor lamps emit yellow light of wavelength 589nm. How much energy is emitted by 5.00 mg of sodium atoms?

Emma Scholes 1L

Can someone explain how to write the formula of compounds.

For example, in question E9 it asks you to write the formula for magnesium sulfate heptahydrate.

Emma Scholes 1L

According to the following equation 0.750 g of C6H9Cl3 is mixed with 1.000 kg of AgNO3 in a flask of water. A white solid, AgCl, completely precipitates out. What is the mass of AgCl produced? C6H9Cl3 + 3AgNO3 --> AgCl + C6H9(NO3)3 Molar Mass : C6H9Cl3 (187.50 g/mol), 3AgNO3 (169.88 g/mol), AgCL (14...

Emma Scholes 1L

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