Search found 64 matches

by Nawal Dandachi 1G
Mon Feb 03, 2020 11:00 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: q and w
Replies: 10
Views: 49

Re: q and w

q would be positive if heat is being added to the system and negative if heat is being removed. w would be positive if work is done by the system and negative if work is done on the system.
by Nawal Dandachi 1G
Sun Feb 02, 2020 9:08 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reaction constant P
Replies: 3
Views: 15

Re: Reaction constant P

it is insignificant when it comes to solids and liquids because there is no change in volume for liquids and solids.
by Nawal Dandachi 1G
Sun Feb 02, 2020 9:03 pm
Forum: Calculating Work of Expansion
Topic: Internal energy
Replies: 5
Views: 11

Re: Internal energy

U is the total energy of a closed system.
by Nawal Dandachi 1G
Sun Feb 02, 2020 9:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Forming bonds
Replies: 8
Views: 19

Re: Forming bonds

When forming a bond, the system loses energy, and because of the decrease in energy, it must have been released, making it exothermic.
by Nawal Dandachi 1G
Sun Feb 02, 2020 8:55 pm
Forum: Phase Changes & Related Calculations
Topic: Phase changes
Replies: 3
Views: 25

Re: Phase changes

depending on whether breaking or forming bonds is occurring, you can determine if it's endo or exo.
by Nawal Dandachi 1G
Sun Feb 02, 2020 8:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Partial Pressure
Replies: 7
Views: 35

Re: Partial Pressure

partial pressure is a pressure exerted by an individual gas in a mixture
by Nawal Dandachi 1G
Thu Jan 23, 2020 2:49 pm
Forum: Phase Changes & Related Calculations
Topic: Calories vs calories
Replies: 5
Views: 12

Re: Calories vs calories

1000 cal = 1 Cal. and for the nutrition facts, they use Cal which is kcal.
by Nawal Dandachi 1G
Thu Jan 23, 2020 2:45 pm
Forum: Ideal Gases
Topic: Equilibrium Constant
Replies: 7
Views: 28

Re: Equilibrium Constant

because k is equal to [products] divided by [reactants], we know that we will end up with a low K value if the [reactant] > [products]. And therefore, there is more reactants
by Nawal Dandachi 1G
Thu Jan 23, 2020 2:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Bases pka and pkb
Replies: 8
Views: 33

Re: Acids and Bases pka and pkb

a low pKa would indicate a strong acid whereas a low pKb would indicate a strong base
by Nawal Dandachi 1G
Thu Jan 23, 2020 2:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice table
Replies: 13
Views: 40

Re: ice table

no you do not include liquids and solids
by Nawal Dandachi 1G
Thu Jan 23, 2020 2:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: pKa to Kb
Replies: 12
Views: 42

Re: pKa to Kb

pKa + pKb = 14, so solve for pKb. After finding pKb, use pKb = -log(kb) to find Kb
by Nawal Dandachi 1G
Sun Jan 12, 2020 2:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homogenous Equilibrium
Replies: 13
Views: 30

Re: Homogenous Equilibrium

homogenous equilibrium is when all reactants and all products are in the same phase
by Nawal Dandachi 1G
Sun Dec 08, 2019 9:36 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen
Replies: 3
Views: 33

Re: Hydrogen

when there's a pair of unshared electrons on F-O-N or when there's a hydrogen that is bonded to F-O-N
by Nawal Dandachi 1G
Sun Dec 08, 2019 9:32 am
Forum: Lewis Structures
Topic: hydrogen bonding
Replies: 2
Views: 24

Re: hydrogen bonding

where there is a pair of unshared electrons on F-O-N or where there is a hydrogen that is bonded to F-O-N
by Nawal Dandachi 1G
Wed Dec 04, 2019 12:10 am
Forum: Air Pollution & Acid Rain
Topic: What do we need to know?
Replies: 4
Views: 70

Re: What do we need to know?

Because Dr. Lavelle mentioned it in lecture before, its safer to know it.
by Nawal Dandachi 1G
Wed Dec 04, 2019 12:08 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong vs Weak Acids and H atoms
Replies: 2
Views: 27

Re: Strong vs Weak Acids and H atoms

I do not think the amount of hydrogen atoms in the acid affects its strength.
by Nawal Dandachi 1G
Wed Dec 04, 2019 12:01 am
Forum: Bronsted Acids & Bases
Topic: Homework Question
Replies: 2
Views: 18

Re: Homework Question

so basically in H2SO3, we know that it contains SO32- sulfite anion. so we can assume that H2SO3 will donate two protons
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:56 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH Sig Figs
Replies: 4
Views: 40

Re: pH Sig Figs

yes, the only thing that has no significance is anything to the left of the decimal point.
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:42 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: J.23
Replies: 2
Views: 30

Re: J.23

An easier way to remember them is to memorize carbonate and sulfate and then simply add an H which would reduces the charge by 1.
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:40 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Hw 6C19
Replies: 3
Views: 31

Re: Hw 6C19

One way to look at it would be to look at the electronegativity. Since Cl is more electronegative than P it would make HClO4 a stronger acid.
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:27 pm
Forum: Lewis Acids & Bases
Topic: 6A.13
Replies: 5
Views: 32

Re: 6A.13

because it's an electron-pair acceptor
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:26 pm
Forum: Hybridization
Topic: HW 2.47
Replies: 1
Views: 16

Re: HW 2.47

yeah they are the n values
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:23 pm
Forum: Naming
Topic: Memorization
Replies: 6
Views: 41

Re: Memorization

yeah i believe so
by Nawal Dandachi 1G
Tue Dec 03, 2019 11:21 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: sigma and pi bonds
Replies: 2
Views: 29

Re: sigma and pi bonds

yeah single bonds have sigma, double have one sigma and one pi and triple bonds have one sigma and two pi
by Nawal Dandachi 1G
Tue Dec 03, 2019 10:44 pm
Forum: Ionic & Covalent Bonds
Topic: polarity of shapes
Replies: 3
Views: 31

Re: polarity of shapes

only if they are symmetric and all the atoms attached to the central atom are the same; however, if the atoms attached to the central atom are not the same, then it is polar.
by Nawal Dandachi 1G
Tue Dec 03, 2019 10:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.3 (b)
Replies: 3
Views: 56

Re: 6B.3 (b)

Since HCl is a strong acid, then we know that it will 100% dissociate, which tells us that the moles of HCl must be equal to the moles of hydronium ions. So, we can use the volume and molarity given to calculate the moles of hydronium ions present. After calculating the number of moles, divide it by...
by Nawal Dandachi 1G
Tue Dec 03, 2019 10:20 pm
Forum: Bronsted Acids & Bases
Topic: Acids and Bases
Replies: 2
Views: 25

Re: Acids and Bases

Acetic acid is a stronger acid because it is stabilized by resonance.
by Nawal Dandachi 1G
Tue Dec 03, 2019 10:12 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Neutral or Negative Acid
Replies: 2
Views: 26

Re: Neutral or Negative Acid

the equation he gave was AH <--> A- + H+ and since the pH>pKa, the solution is more alkaline, and the acid will give off H+ to form A-. This basically meant that when AH dissociated, it formed A- which is negative so its negatively charged.
by Nawal Dandachi 1G
Tue Dec 03, 2019 10:03 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6C17 - strength of bases
Replies: 4
Views: 50

Re: 6C17 - strength of bases

morphine is basic because it contains a nitrogen with a lone pair. However, BrO- is a conjugate base of a weak acid, so its a stronger base.
by Nawal Dandachi 1G
Tue Dec 03, 2019 9:52 pm
Forum: Bronsted Acids & Bases
Topic: J.9 calcium hydroxide and bromous acid
Replies: 1
Views: 32

Re: J.9 calcium hydroxide and bromous acid

the salt would be calcium bromide, Ca(BrO2)2
HBrO2 + Ca(OH)2 --> H2O + Ca(BrO2)2
by Nawal Dandachi 1G
Tue Dec 03, 2019 9:40 pm
Forum: Bronsted Acids & Bases
Topic: CaO
Replies: 10
Views: 59

Re: CaO

It is considered a strong base because it completely dissociates when it is added to water.
by Nawal Dandachi 1G
Tue Dec 03, 2019 9:38 pm
Forum: Lewis Acids & Bases
Topic: How to identify acid vs. base
Replies: 4
Views: 38

Re: How to identify acid vs. base

lewis acid is an electron-pair acceptor while a lewis base is an electron-pair donor.
by Nawal Dandachi 1G
Tue Dec 03, 2019 9:36 pm
Forum: Lewis Acids & Bases
Topic: Naming Acids
Replies: 3
Views: 22

Re: Naming Acids

I think we should know the common ones, but maybe know them just in case
by Nawal Dandachi 1G
Tue Dec 03, 2019 9:33 pm
Forum: Student Social/Study Group
Topic: Paramagnetic and Diamagnetic
Replies: 2
Views: 41

Re: Paramagnetic and Diamagnetic

I don't think we need to know this
by Nawal Dandachi 1G
Tue Dec 03, 2019 12:01 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7834
Views: 1088658

Re: Post All Chemistry Jokes Here

What did one charged atom say to the other?
I got my ion you!
by Nawal Dandachi 1G
Tue Dec 03, 2019 12:00 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7834
Views: 1088658

Re: Post All Chemistry Jokes Here

AU! THESE JOKES ARE GOLD, SO READ 'EM
by Nawal Dandachi 1G
Mon Dec 02, 2019 10:13 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong Acids
Replies: 3
Views: 23

Re: Strong Acids

yeah i think so just in case
by Nawal Dandachi 1G
Mon Dec 02, 2019 9:47 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Today's lecture
Replies: 5
Views: 41

Re: Today's lecture

He talked about ions as acids and bases.
by Nawal Dandachi 1G
Mon Dec 02, 2019 9:44 pm
Forum: Lewis Acids & Bases
Topic: Problem J.9
Replies: 4
Views: 43

Re: Problem J.9

it would produce water and potassium acetate.
CH3COOH + K(OH) → H2O + CH3COOK
by Nawal Dandachi 1G
Mon Dec 02, 2019 9:39 pm
Forum: Bronsted Acids & Bases
Topic: stronger acid ?
Replies: 3
Views: 26

Re: stronger acid ?

HClO2 is a stronger acid than HBrO2 because Cl has a higher electronegativity than Br.
by Nawal Dandachi 1G
Mon Dec 02, 2019 9:10 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Carbonate Ion
Replies: 2
Views: 25

Re: Carbonate Ion

This is due to carbonate's resonance and lewis structure. Because of its structure, there is 120 degrees between its oxygens so two oxygens can not bind to the same metal making it mono dentate. However, there are some cases where carbonate bonds to different metals which makes it bidentate.
by Nawal Dandachi 1G
Mon Dec 02, 2019 9:02 pm
Forum: Conjugate Acids & Bases
Topic: What are some examples of basic oxides and acidic oxides?
Replies: 2
Views: 22

Re: What are some examples of basic oxides and acidic oxides?

Some acidic oxides include SO2, CO2, NO2, ClO2 and some basic oxides include CaO and BaO
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:44 pm
Forum: Amphoteric Compounds
Topic: Oxides
Replies: 1
Views: 20

Re: Oxides

When the oxide is added to water and it forms an acid, then it is an acidic oxide. When an oxide is added to water and forms a base, then it is a basic oxide. And when an oxide is added to water and has the ability to form both an acid and base, then it is amphoteric.
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:41 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH sigfigs
Replies: 3
Views: 31

Re: pH sigfigs

The numbers to the left of the decimal point of the pH has no significance, so for example, a pH of 4.22 would correspond to a concentration that only has two sig figs and not three.
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:37 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pH and pKa
Replies: 2
Views: 34

Re: pH and pKa

AH <--> A- + H+
since the pH>pKa, the solution is more alkaline, and the acid will give off H+ to form A-. Therefore, it is negatively charged.
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:32 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Outline topic
Replies: 2
Views: 25

Re: Outline topic

At the same concentration, weak acids have a higher pH than strong acids because weak acids partially dissociate whereas strong acids fully dissociate. therefore, strong acids have a higher hydronium concentration, and the higher the hydronium concentration, the lower the pH.
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:26 pm
Forum: Bronsted Acids & Bases
Topic: Oxoacids
Replies: 2
Views: 21

Re: Oxoacids

it's any acid that contains oxygen bonded to a hydrogen atom and one or more other elements.
by Nawal Dandachi 1G
Mon Dec 02, 2019 8:13 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Conjugate Seesaw [ENDORSED]
Replies: 2
Views: 45

Re: Conjugate Seesaw [ENDORSED]

i think all you need to know is that the stronger the acid is, the weaker its conjugate base. and the stronger the base is, the weaker its conjugate acid is.
by Nawal Dandachi 1G
Sat Nov 30, 2019 3:10 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook question 6C.21
Replies: 1
Views: 21

Re: Textbook question 6C.21

When we look at the conjugate bases for these two acids, the only difference is that there's a methyl group attached adjacent to the carbonyl group in the conjugate base for acetic acid while the conjugate base for formic acid only has a hydrogen attached adjacent to the carbonyl group. The methyl g...
by Nawal Dandachi 1G
Sat Nov 30, 2019 3:01 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 3
Views: 31

Re: Final Exam

12/8/2019 and three hours long
by Nawal Dandachi 1G
Sat Nov 30, 2019 2:45 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.3
Replies: 2
Views: 31

Re: 6B.3

Since HCl is a strong acid, then we know that it will 100% dissociate, which tells us that the moles of HCl must be equal to the moles of hydronium ions. So, we can use the volume and molarity given to calculate the moles of hydronium ions present. After calculating the number of moles, divide it by...
by Nawal Dandachi 1G
Sat Nov 30, 2019 2:25 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: 6C.17
Replies: 1
Views: 40

Re: 6C.17

Hypobromite ion, BrO-, is a conjugate base of a weak acid, and therefore it must be a strong base. Morphine, C17H19O3N, has a lone pair located on the nitrogen, so it's a weaker base.
by Nawal Dandachi 1G
Mon Oct 14, 2019 9:42 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A.11 What is common to each series that groups their spectral lines together?
Replies: 2
Views: 17

Re: 1A.11 What is common to each series that groups their spectral lines together?

The common aspect in each series is that the energy levels from which an electron starts or returns to is the same for anything in that series. For example, in the Balmer series, the electrons always return from or start from the energy level n=2. Same goes for the Lyman series, where e- start or re...
by Nawal Dandachi 1G
Mon Oct 14, 2019 9:36 am
Forum: Properties of Light
Topic: 1A.15
Replies: 4
Views: 93

Re: 1A.15

Because the emission is ultraviolet, then we know that this transition is happening in the Lyman series. So the final energy level is going to be n=1. The initial energy level could be anything greater than 1. You can then use Rydberg's equation to find n1.
by Nawal Dandachi 1G
Mon Oct 14, 2019 9:24 am
Forum: Properties of Electrons
Topic: 1F.5 Question
Replies: 2
Views: 25

Re: 1F.5 Question

Yes, you would be able to use a periodic table. So ionization energy increases going up a periodic table and increases going left to right.
by Nawal Dandachi 1G
Mon Oct 14, 2019 9:17 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Positive & Negative Signs on Energy Levels
Replies: 2
Views: 20

Re: Positive & Negative Signs on Energy Levels

The negative sign of energy just means that the electron of that atom has a lower energy than the free electron which is zero energy.
by Nawal Dandachi 1G
Mon Oct 14, 2019 9:03 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Are these equations only specific to H-atoms?
Replies: 2
Views: 33

Re: Are these equations only specific to H-atoms?

For the bohr frequency condition, the equation contains Rydberg's constant (3.29x10^15 Hz); and that constant only works on hydrogen atoms or hydrogen-like atoms such as He+.
by Nawal Dandachi 1G
Sat Oct 05, 2019 12:07 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration order
Replies: 4
Views: 49

Re: Electron configuration order

I agree with the commenter before me. The position of the 3d orbital is at a higher level than the 4s orbital; therefore, the 4s orbital would fill up before the the 3d orbital.
by Nawal Dandachi 1G
Sat Oct 05, 2019 12:02 am
Forum: Administrative Questions and Class Announcements
Topic: Frequency of posting
Replies: 2
Views: 29

Re: Frequency of posting

I think they are due on Sunday not sure though
by Nawal Dandachi 1G
Fri Oct 04, 2019 11:30 pm
Forum: Molarity, Solutions, Dilutions
Topic: G23
Replies: 2
Views: 38

Re: G23

I got a concentration of 0.13 M of chloride ions. I do not think it matters because when both of these compounds dissociate the mole ratio between the compound and Cl- is 1:1. For example, 1 mole of sodium chloride would dissociate to 1 mole of Na+ and 1 mole of Cl-, so there's no need to separate t...
by Nawal Dandachi 1G
Fri Oct 04, 2019 11:23 pm
Forum: Balancing Chemical Reactions
Topic: Textbook H19
Replies: 1
Views: 31

Re: Textbook H19

I believe it would be C14H18N2O5(s) + 16O2(g) --> 14CO2(g) + 9H20(l) + N2(g)
by Nawal Dandachi 1G
Fri Oct 04, 2019 11:17 pm
Forum: Limiting Reactant Calculations
Topic: Textbook M15-Calculation?
Replies: 3
Views: 35

Re: Textbook M15-Calculation?

maybe you should recalculate because when I computed it, I got 671 grams of aluminum chloride produced. And then the percent yield would be like 44.7%

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