Search found 30 matches

by varunhariharan
Sat Mar 16, 2019 6:44 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

Q: What do you call a tooth in a glass of water?
A: One molar solution.
by varunhariharan
Sat Mar 16, 2019 6:43 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

Q: Why does hamburger yield lower energy than steak?
A: Because it's in the ground state.
by varunhariharan
Sat Mar 16, 2019 2:27 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

Q: What do you do with a sick chemist?
A: If you can't helium and you can't curium, then you may as well barium
by varunhariharan
Sat Mar 16, 2019 2:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

Why do chemists find working with ammonia easy?
Because it’s pretty basic stuff.
by varunhariharan
Fri Mar 15, 2019 6:14 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

I am trying to think of more chemistry jokes by they all argon...
by varunhariharan
Fri Mar 15, 2019 6:13 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 912587

Re: Post All Chemistry Jokes Here

Q: What do you do with a sick chemist?
A. First you try to helium, then you try to curium, but if this fails then you have to barium.
by varunhariharan
Thu Mar 14, 2019 10:43 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Finding rate constant
Replies: 2
Views: 119

Re: Finding rate constant

The production of B is half the rate of the disappearance of A. With stoichiometry from there, the concentration of A must have decreased by 2(0.034 M) = 0.068M. This should be subtracted from the initial concentration of A to determine the concentration after 115s. Then ln([A]/[A0])=-kt should be u...
by varunhariharan
Thu Mar 14, 2019 10:36 am
Forum: General Rate Laws
Topic: reaction rate(s)?
Replies: 4
Views: 116

Re: reaction rate(s)?

A reaction rate compares the change in concentration over time. A rate law relates the rate of reaction to the concentrations of the reactants which are modified by an exponent representing the reaction order.
by varunhariharan
Wed Mar 13, 2019 1:09 pm
Forum: General Rate Laws
Topic: rate laws and graphs
Replies: 3
Views: 43

Re: rate laws and graphs

It is important to know what the integrated rate law for a 0, 1st, and 2nd order looks like when graphed, as well as what would cause them to be a straight line.
by varunhariharan
Tue Mar 12, 2019 9:47 am
Forum: General Rate Laws
Topic: Zero Order Reactions
Replies: 4
Views: 77

Re: Zero Order Reactions

In a zero order reaction the rate does not depend on the concentration. This means the concentration will change linearly compared to time regardless of the rate constant.
by varunhariharan
Tue Mar 12, 2019 9:36 am
Forum: First Order Reactions
Topic: Doubling the Concentration
Replies: 4
Views: 50

Re: Doubling the Concentration

The reaction rate and the order of a reaction are two separate concepts. In rate=k[A], doubling [A] would double the rate of reaction. Increasing the order of the reaction would exponentially increase the rate, as the rate would equal k[A].
by varunhariharan
Thu Mar 07, 2019 3:44 pm
Forum: First Order Reactions
Topic: First order graph
Replies: 7
Views: 103

Re: First order graph

The x-intercept shows how much time time (t) it takes for the natural log of [A] to equal zero, and for [A] to equal zero.
by varunhariharan
Wed Mar 06, 2019 11:15 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: kinetics and thermodynamics
Replies: 4
Views: 88

Re: kinetics and thermodynamics

Neither is prevalent in controlling a reaction; they each refer to different concepts. Kinetics has to do with the rates of reactions, while thermodynamics focuses on changes in energy during reactions and spontaneity.
by varunhariharan
Mon Mar 04, 2019 5:32 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: K
Replies: 5
Views: 65

Re: K

This can be seen using ΔG = -RTlnK

When K>1, then lnK is positive, and ΔG is negative.
When K<1, then lnK is negative, and ΔG is positive.
by varunhariharan
Thu Feb 28, 2019 9:17 pm
Forum: Balancing Redox Reactions
Topic: oxidizing agent and reducing agent
Replies: 15
Views: 176

Re: oxidizing agent and reducing agent

An oxidizing agent oxidizes another atom, meaning that it gains an electron by removing an electron from another atom. A reducing agent reduces another atom, meaning that it loses an electron giving one to another atom. In essence, oxidizing agents are reduced, and reducing agents are oxidized.
by varunhariharan
Thu Feb 28, 2019 4:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding n
Replies: 12
Views: 189

Re: Finding n

n is the number of electrons being transferred. However, make sure that both half-reactions are balanced before using n, as the number of electrons being transferred should stay consistent in the equation.
by varunhariharan
Thu Feb 28, 2019 4:16 pm
Forum: Balancing Redox Reactions
Topic: Basic Solutions
Replies: 5
Views: 77

Re: Basic Solutions

For basic solutions, H2O is used to balance the hydrogens. Then, when balancing oxygens, OH- should be added, and then H2O may need to be added again if the Hydrogens become unbalanced due to the addition of OH-.
by varunhariharan
Thu Feb 28, 2019 4:14 pm
Forum: Balancing Redox Reactions
Topic: Oxidation state
Replies: 2
Views: 45

Re: Oxidation state

Find the total charge on either side of the equation by multiplying the coefficients with the charges. Then electrons should be added to the side with a more positive charge to balance the equation charges.
by varunhariharan
Mon Feb 25, 2019 2:10 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Moles in -nFEcell
Replies: 5
Views: 96

Re: Moles in -nFEcell

To find n, you must write out both of the half reactions and balance the equations. Once the number of electrons on both sides of the reaction are consistent, this is how many moles should be used in this equation.
by varunhariharan
Mon Feb 25, 2019 2:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 6
Views: 66

Re: Anode and Cathode

In a cell, electrons move from the anode to the cathode. This is because electrons are lost at the anode, where oxidation occurs, and are gained at thee anode, where reduction occurs.
by varunhariharan
Mon Feb 25, 2019 9:58 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q=mCdeltaT
Replies: 11
Views: 443

Re: q=mCdeltaT

The units either way should be in Joules because the moles/grams unit will be cancelled in the equation by the specific heat capacity.
by varunhariharan
Mon Feb 25, 2019 9:46 am
Forum: Balancing Redox Reactions
Topic: Adding OH- and H20 into reactions
Replies: 3
Views: 54

Re: Adding OH- and H20 into reactions

For a basic solution, H2O is added to balance the O atoms in the balanced equation. Next, H2O is added to balance the Hydrogens, and OH- is added to the other side of the equation to make up for the excess Hydrogen atoms.
by varunhariharan
Tue Feb 19, 2019 3:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Relationship between enthalpy, entropy, and Gibbs
Replies: 4
Views: 59

Re: Relationship between enthalpy, entropy, and Gibbs

\Delta G = \Delta H - T \Delta S In order for the reaction to be spontaneous, ΔG = -, so: If ΔH = - , and ΔS = + , the reaction is spontaneous at any temperature. If ΔH = - , and ΔS = - , the reaction is spontaneous at low temperature. If ΔH = + , and ΔS = + , the reaction is spontaneous at high te...
by varunhariharan
Wed Feb 13, 2019 9:11 am
Forum: Phase Changes & Related Calculations
Topic: 4.18J or 0.38J
Replies: 8
Views: 224

Re: 4.18J or 0.38J

The specific heat capacity of water is either 4.186 J/gK or 75.2 J/molK .
by varunhariharan
Fri Feb 08, 2019 9:22 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 3
Views: 57

Re: Bond Enthalpies

Drawing the Lewis structures of larger molecules can make the calculation much easier in the long run, so I think getting into the habit of drawing them out to get a better visualization of the bond enthalpies makes sense.
by varunhariharan
Fri Feb 08, 2019 9:20 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: ΔH
Replies: 2
Views: 68

Re: ΔH

ΔH represents the change in energy, so there are different equations based on the information you are provided in the problem (ie. bond enthalpy, enthalpy of vaporization, calorimetry, etc.)
by varunhariharan
Fri Feb 08, 2019 9:17 am
Forum: Phase Changes & Related Calculations
Topic: Units of enthalpy
Replies: 5
Views: 98

Re: Units of enthalpy

ΔH is usually expressed in kJ/mol
by varunhariharan
Sun Jan 27, 2019 3:53 pm
Forum: Phase Changes & Related Calculations
Topic: Delta H
Replies: 11
Views: 167

Re: Delta H

\Delta H = H_{products} - H_{reactants} , H being enthalpy. If the enthalpy, or total energy, of the products is greater than the energy of the reactants, then ΔH is positive and it is an endothermic reaction. If the energy of the products is less than the energy of the reactants, ΔH is negative an...
by varunhariharan
Sun Jan 27, 2019 3:37 pm
Forum: Phase Changes & Related Calculations
Topic: Why are phase changes endothermic?
Replies: 11
Views: 123

Re: Why are phase changes endothermic?

These phase changes all require bonds to be broken which require an input of energy.
by varunhariharan
Wed Jan 23, 2019 9:46 am
Forum: Phase Changes & Related Calculations
Topic: Endothermic or Exothermic
Replies: 20
Views: 502

Re: Endothermic or Exothermic

Condensation is an exothermic reaction. As the water molecules change phase from gas to liquid, energy is released.

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