## Search found 44 matches

Mon Mar 07, 2016 8:15 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Different Strains
Replies: 3
Views: 615

### Different Strains

What's the difference between torsional and steric strain? Would it be possible to have both at the same time?
Fri Mar 04, 2016 10:56 am
Forum: *Calculations Using ΔG° = -RT ln K
Topic: Delta G
Replies: 1
Views: 818

### Delta G

What is the difference between delta G of a reaction and delta G double dagger?
Sun Feb 28, 2016 5:31 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Activated complex
Replies: 1
Views: 475

### Activated complex

How do you draw the structure for an activated complex & what exactly does the structure represent?
Wed Feb 24, 2016 5:37 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Symbols
Replies: 2
Views: 1240

### Symbols

What exactly does the double plus sign (it looks like a t) symbol mean? What does it mean when a variable has that?
Thu Feb 18, 2016 10:18 pm
Forum: General Rate Laws
Topic: Order of a reaction
Replies: 1
Views: 327

### Order of a reaction

How can we determine the order of a reaction from the units of the rate constant?
Sun Feb 07, 2016 7:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Bond Enthalpies
Replies: 1
Views: 297

### Calculating Bond Enthalpies

When we balance an equation sometimes the O will have a fraction in front of it. So are we supposed to calculate the enthalpy with the fraction or are we supposed to balance the equation again until we have no fraction coefficients? I know sometimes it'll explicitly say "for one mole of....&quo...
Thu Feb 04, 2016 6:06 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated Systems
Replies: 1
Views: 360

### Isolated Systems

Is any isolated system always going to be constant volume?
Wed Feb 03, 2016 10:37 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Homework Problem 9.101
Replies: 1
Views: 275

### Homework Problem 9.101

A neat pump heats a house in winter by extracting heat from the cold outdoors and releasing it into the warm interior For the transfer of a given amount of heat. (a) How do the entropies of the interior and exterior of the house change (increase or decrease)? (b) Which change is greater? Assume that...
Wed Jan 27, 2016 6:26 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Delta V
Replies: 2
Views: 1140

### Delta V

Why is delta V = 0 in an isolated system?
Sat Jan 23, 2016 5:42 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal ???
Replies: 1
Views: 335

### Isothermal ???

When temperature is constant but volume changes, why is the change in internal energy equal to 0?
Thu Jan 21, 2016 8:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeter Calculation
Replies: 2
Views: 387

### Bomb Calorimeter Calculation

What do each of the variables mean in the equation qP= delta H = gCsp delta T?
Also, is a bomb calorimeter closed or isolated? Is it always the same case?
Thu Jan 21, 2016 8:27 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heating in DIfferent Systems
Replies: 1
Views: 346

### Heating in DIfferent Systems

What is the difference between heating in a closed system vs heating in an isolated system? How does it affect other values? What exactly happens when either of the systems are heated?
Thu Jan 21, 2016 8:25 pm
Forum: Calculating Work of Expansion
Topic: Types of Systems
Replies: 3
Views: 637

### Types of Systems

Are reversible processes always a certain type of system (closed, isolated, open)? What about irreversible processes? Like for reversible processes is it always going to be the same type of system or can it be different?
Thu Jan 21, 2016 8:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversible and Irreversible
Replies: 1
Views: 321

### Reversible and Irreversible

Can a rxn ever be reversible with a changing temperature or will it always be isothermal when it is reversible? Why? If it is possible to have a delta P and a delta T for a reversible rxn, how would we calculate it?
Sun Jan 17, 2016 11:40 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units
Replies: 2
Views: 395

### Units

Is delta H in units of kJ or kJ/mol?
Sun Jan 17, 2016 10:19 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.25
Replies: 2
Views: 602

### Re: Homework Problem 8.25

Hi! Based on your calculations, you found C, the heat capacity of the entire calorimeter (rather than its specific heat capacity) is 0.478 kJ/K. We can use the equation q = - C x delta T to find how much heat the reaction released into the calorimeter. We know delta T is 2.49 K using the given chan...
Sun Jan 17, 2016 7:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.53
Replies: 1
Views: 386

### Homework Problem 8.53

The reaction of 1.40g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bmb calorimeter causes the temp of the calorimeter assembly to rise from 22.113C to 22.799C. The calorimeter assembly is known to have a total heat capacit of 3.00 kJ/C. Calculate the i...
Sun Jan 17, 2016 7:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.25
Replies: 2
Views: 602

### Homework Problem 8.25

#25: A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200L of solution in the calorimeter, (q=-3.50kJ) resulting in a temperature rise of 7.32C. In a subsequent experiment, 100.0 mL of 0.200 M HBr(aq) and 100.0 mL of 0.200M KOH (aq) were m...
Sun Jan 17, 2016 7:06 pm
Forum: Phase Changes & Related Calculations
Topic: Bomb Calorimeter
Replies: 2
Views: 620

### Re: Bomb Calorimeter

Thank you!
Sun Jan 17, 2016 7:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Question
Replies: 3
Views: 875

### Homework Question

For #117 the question is: What is the change in internal energy for the production of 1.00 mol H 2 ? Given the reaction: CH 4(g) +H 2 O (g) --> CO 2(g) + 3H 2(g) I saw the answer on the solutions manual but I don't really understand the work. Can someone explain this ...
Thu Jan 14, 2016 11:27 am
Forum: Phase Changes & Related Calculations
Topic: Calculating Work
Replies: 4
Views: 1886

### Calculating Work

Air in a bicycle pump is compressed by pushing in the handle. If the inner diameter of the pump is 3.0 cm and the pump is depressed 20 cm with a pressure of 2.00 atm. How much work is done in the compression? I know how to get to the answer because my TA briefly went over this problem, but can someo...
Wed Jan 13, 2016 6:39 pm
Forum: Phase Changes & Related Calculations
Topic: Bomb Calorimeter
Replies: 2
Views: 620

### Bomb Calorimeter

A bomb calorimeter in which benzene is burned is an isolated system, why? Also, can you explain the different types of calorimeters there are (constant pressure, constant volume) and how they work? Thanks!
Fri Jan 08, 2016 5:34 pm
Forum: Phase Changes & Related Calculations
Topic: Different types of systems
Replies: 3
Views: 531

### Different types of systems

I'm really confused on the differences between open, closed, & isolated systems.
One sample question would be like why is a plant an open system? If someone could explain the systems to me in detail that'd be great. Thanks!
Fri Dec 04, 2015 4:52 pm
Forum: *Titrations & Titration Calculations
Topic: Initial Concentrations
Replies: 1
Views: 321

### Initial Concentrations

When given a problem, how do you know when you have concentrations >0 in the reactants and products as opposed to only having a concentration >0 in the reactants and 0 in the products?
Tue Nov 24, 2015 6:14 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Delocalization of Negative Charges
Replies: 1
Views: 678

### Delocalization of Negative Charges

Why is trichloroacetic acid (CCl3COOH, pKa=0.52) a stronger acid than acetic acid (CH3COOH, pKa=4.75)? Can someone explain the answer in depth please? I know it has something to do with delocalization of negative charge, what exactly does that mean?
Tue Nov 17, 2015 3:36 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Midterm Question
Replies: 1
Views: 363

### Midterm Question

So on the midterm one of the questions was "Explain the order of electron filling in atoms of K, Ca, and Sc. Give the abbreviated electron configurations to illustrate your answer." In the explanation, it said that for K and Ca, the 4s orbital was lower in energy than 3d but in Sc 3d was l...
Tue Nov 17, 2015 2:34 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Biological Importance
Replies: 1
Views: 433

### Biological Importance

Hi, I'm having a bit of trouble understanding the reaction of hemoglobin and oxygen in the process of homeostasis, can somebody explain it thoroughly for me please? Hb (aq) + O 2(aq) <--> HbO 2(aq) Also, can you compare this to myoglobin and explain what the relationship betw...
Tue Nov 17, 2015 2:22 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small Amount of K
Replies: 2
Views: 273

### Re: Small Amount of K

Thank you so much! You explained it really well, I get it now.
Tue Nov 17, 2015 2:19 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating the equilibrium composition
Replies: 4
Views: 448

### Re: Calculating the equilibrium composition

Oh okay, I completely understand it now. Thank you
Mon Nov 09, 2015 11:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Small Amount of K
Replies: 2
Views: 273

### Small Amount of K

So in the course reader on page 127 it stated that since Kc was a really small value, we could assume that the concentrations would be unchanged. Why exactly is this value used as the "x" value?
Mon Nov 09, 2015 11:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating the equilibrium composition
Replies: 4
Views: 448

### Re: Calculating the equilibrium composition

Like on the ICE chart, how do we know if it should be +x,-x, +2x, etc.?
Sun Nov 08, 2015 1:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating the equilibrium composition
Replies: 4
Views: 448

### Calculating the equilibrium composition

how do we determine the change in molar concentration?
Sat Oct 31, 2015 7:29 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 1
Views: 253

### Lewis Structures

For something like CH3COO- how do you know that the extra O is connected to C and not to O? Or if it ended in OH insted of OO how do you know the H would be connected to the C and not the O?
Mon Oct 26, 2015 7:17 pm
Forum: Lewis Structures
Topic: Resonance Structures
Replies: 1
Views: 258

### Resonance Structures

How can you find the most stable lewis structure without having to draw out all the resonance structures?
Wed Oct 21, 2015 11:22 pm
Forum: Lewis Structures
Topic: General Rules
Replies: 1
Views: 418

### General Rules

So for lewis structures, I'm not really sure how to do it. If i had something like XeF 4 I would have a lewis structure in an "x" or a "T" shape? Also, for a structure such as CH 3 CO 2 - how would I know that the lewis structure would sort of look like 2 different lewis structur...
Mon Oct 12, 2015 7:30 pm
Forum: Photoelectric Effect
Topic: How to find the kinetic energy of ejected electrons?
Replies: 4
Views: 3858

### Re: How to find the kinetic energy of ejected electrons?

thank you
Mon Oct 12, 2015 7:29 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 439

### Re: Schrodinger Equation

ok, thank you
Mon Oct 12, 2015 7:29 pm
Forum: DeBroglie Equation
Topic: Wavelike properties in larger objects [ENDORSED]
Replies: 2
Views: 503

### Re: Wavelike properties in larger objects[ENDORSED]

thank you
Mon Oct 12, 2015 7:28 pm
Forum: Empirical & Molecular Formulas
Topic: How to find the empirical formula being given only masses?
Replies: 3
Views: 651

### Re: How to find the empirical formula being given only masse

thank you
Mon Oct 12, 2015 5:47 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Overall Charge Calculations
Replies: 1
Views: 428

### Re: Overall Charge Calculations

First, you're going to find how many valence electrons the element has (refer to the periodic table). Then, on the Lewis structure of the compound, you're going to see bonds like this - and bonds that are black circles. the black circles are your "lone pair" electrons, your L value. the sh...
Tue Oct 06, 2015 10:40 pm
Forum: DeBroglie Equation
Topic: Wavelike properties in larger objects [ENDORSED]
Replies: 2
Views: 503

### Wavelike properties in larger objects[ENDORSED]

When solving the De Broglie equation for an object with a large mass (such as a baseball's mass) the wavelength is so small it cannot be detected. Does this mean that there are no wavelike properties in everyday objects or does it just mean that they are not detectable? If we were to be asked on a t...
Mon Oct 05, 2015 6:26 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 439

### Schrodinger Equation

I really don't understand the equation itself. I know that you can find the wavefunctions by solving the equation but what does this actually mean?
Tue Sep 29, 2015 8:49 pm
Forum: Photoelectric Effect
Topic: How to find the kinetic energy of ejected electrons?
Replies: 4
Views: 3858

### How to find the kinetic energy of ejected electrons?

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. What is the kinetic energy of the ejected electron? I did see a previous post with this question but it wasn't clear to me how to actually solve it. If I us...
Mon Sep 28, 2015 6:53 pm
Forum: Empirical & Molecular Formulas
Topic: How to find the empirical formula being given only masses?
Replies: 3
Views: 651

### How to find the empirical formula being given only masses?

A compound found in the nucleus of a human cell was found to be composed of carbon, hydrogen, oxygen, and nitrogen. A combustion analysis of 1.35 g of the compound produced 2.20 g of CO 2 and 0.901 g of H 2 O. When a separate 0.500g sample of the compound was analyzed for nitrogen, 0.130g of N 2 was...

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