Search found 71 matches

by ZainAlrawi_1J
Sat Dec 07, 2019 2:43 pm
Forum: Conjugate Acids & Bases
Topic: How was this equation derived?? Marshmallow #34
Replies: 1
Views: 125

How was this equation derived?? Marshmallow #34

Lyndon sees his crush and panics, accidentally dropping 382.7 mg of HCl and 147.1 mg CaO into a 1L flask. After filling that flask with water up to the 1L mark, what is the pH of the resulting solution? How do you go about deriving the equation HCl + Cao --> CaCl2 + H2O from this starting to point? ...
by ZainAlrawi_1J
Thu Dec 05, 2019 11:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: what is an oxidation number?
Replies: 1
Views: 45

Re: what is an oxidation number?

The oxidation number is the charge of a particular atom or molecule.
The coordination number is the number of separate points at which ligands attach to a central atom
by ZainAlrawi_1J
Thu Dec 05, 2019 11:10 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: bond strength v electronegativity
Replies: 2
Views: 45

Re: bond strength v electronegativity

Refer to table 6C.7 in the book to clear up this confusion on how to determine acid strengths, I have it attached here: https://i.imgur.com/IFnknpN.png
by ZainAlrawi_1J
Thu Dec 05, 2019 11:03 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: H2CO3 vs H2GeO3 [ENDORSED]
Replies: 3
Views: 75

Re: H2CO3 vs H2GeO3 [ENDORSED]

Both of these are oxoacids, both oxoacids have the same number of Oxygen atoms, so you take a look at the electronegativity of the attached group. H2C is more electronegative than HGe (C is more electronegative than Ge), therefore it is the stronger acid.
by ZainAlrawi_1J
Thu Dec 05, 2019 5:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: -ate
Replies: 11
Views: 253

Re: -ate

You use -ate with negatively charged atoms.
by ZainAlrawi_1J
Thu Dec 05, 2019 5:07 pm
Forum: Naming
Topic: 9C.1 a
Replies: 3
Views: 39

Re: 9C.1 a

Both 'cyano' and 'cyanido' refer to CN- and both are accepted for this class. Please refer to the following document that Dr. Lavelle emailed us: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf I would personally stick to the traditional naming schem...
by ZainAlrawi_1J
Thu Dec 05, 2019 5:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining Coordination Number
Replies: 2
Views: 54

Re: Determining Coordination Number

You would count a double bond as a single point, except in the case of molecules with polydentate qualities, that are able to bind to the central metal in more than one place. These molecules could contribute more attachments to the bonding number.
by ZainAlrawi_1J
Thu Dec 05, 2019 4:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C.21 B)
Replies: 1
Views: 35

Re: 6C.21 B)

It is important to first note that both CH3COOH and HCOOH are Carboxylic Acids, meaning that they both contain the COOH group, and as such we can use the information summarized in Table 6C.7 of the textbook in order to understand how to derive which of the two is the stronger acid. For carboxylic ac...
by ZainAlrawi_1J
Wed Dec 04, 2019 4:39 pm
Forum: Hybridization
Topic: 2.45 Hybridization
Replies: 3
Views: 66

2.45 Hybridization

Can someone explain how the hybridization of the lone pairs in part b of this question are derived? I have never seen a question like this before and I'm not even sure that we have went over it.
by ZainAlrawi_1J
Fri Nov 29, 2019 2:43 pm
Forum: Hybridization
Topic: Sigma and Pi bonds
Replies: 7
Views: 98

Re: Sigma and Pi bonds

A single bond is a sigma bond.
A double bond consists of one sigma bond, one pi bond
A triple bond consists of one sigma bond, two pi bonds.
by ZainAlrawi_1J
Fri Nov 29, 2019 2:34 pm
Forum: Hybridization
Topic: Reason for 1 sigma and multiple pi bonds
Replies: 3
Views: 36

Re: Reason for 1 sigma and multiple pi bonds

There must be a side by side overlap between orbitals in order for them to form double or triple bonds, this specific arrangement, wherein orbitals are bonded side by side as opposed to end to end, is referred to as pi bonding.
by ZainAlrawi_1J
Fri Nov 29, 2019 2:32 pm
Forum: Bronsted Acids & Bases
Topic: Acid vs Base
Replies: 4
Views: 82

Re: Acid vs Base

Bronsted acids usually start with a Hydrogen "H" atom, while Bronsted bases usually end in an Oxygen and Hydrogen "OH"
by ZainAlrawi_1J
Fri Nov 29, 2019 2:30 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: cis platinum
Replies: 6
Views: 68

Re: cis platinum

Cisplatin helps in mitigating cancerous cell mutation, it is an important example to know the structure and significance of for this course.
by ZainAlrawi_1J
Fri Nov 29, 2019 2:15 pm
Forum: Conjugate Acids & Bases
Topic: Definition of conjugate base
Replies: 6
Views: 301

Re: Definition of conjugate base

When in an acid loses a hydrogen atom in a chemical reaction, the formed compound is called the conjugate base.
by ZainAlrawi_1J
Fri Nov 29, 2019 2:14 pm
Forum: Bronsted Acids & Bases
Topic: Weak Acid Strength
Replies: 3
Views: 44

Re: Weak Acid Strength

The more electronegative an atom, the weaker the acids it will form.
by ZainAlrawi_1J
Mon Nov 25, 2019 11:24 am
Forum: Resonance Structures
Topic: Resonance
Replies: 5
Views: 182

Re: Resonance

2 charges of 1 or -1 is usually preferable.
by ZainAlrawi_1J
Mon Nov 25, 2019 11:17 am
Forum: Electronegativity
Topic: Electronegativity
Replies: 15
Views: 310

Re: Electronegativity

Electronegativity is correlated with shorter bond lengths, which are also stronger bonds by virtue of their compactness
by ZainAlrawi_1J
Mon Nov 25, 2019 11:13 am
Forum: Naming
Topic: Naming
Replies: 3
Views: 43

Re: Naming

Yes, we have to understand the naming algorithm for coordination compounds.
by ZainAlrawi_1J
Mon Nov 25, 2019 11:11 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: bond order
Replies: 4
Views: 120

Re: bond order

Bond order is defined as the difference between the # of bonds and the # of antibonds
by ZainAlrawi_1J
Mon Nov 25, 2019 11:11 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: bond order
Replies: 4
Views: 120

Re: bond order

Bond order is defined as the difference between the # of bonds and the # of antibonds
by ZainAlrawi_1J
Mon Nov 25, 2019 11:09 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs linear
Replies: 56
Views: 1129

Re: Bent vs linear

Bent molecules have a lone pair.
by ZainAlrawi_1J
Mon Nov 25, 2019 11:07 am
Forum: Sigma & Pi Bonds
Topic: Pi Bonding
Replies: 6
Views: 88

Re: Pi Bonding

Pi bonds exist in all double and triple bonds
by ZainAlrawi_1J
Thu Nov 21, 2019 5:52 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Strengths
Replies: 2
Views: 89

Re: Bond Strengths

Strongest to weakest:

1. Ion-Ion
2. Ion-Dipole
3. Hydrogen Bond
4. Dipole-Dipole
5. London Dispersion
by ZainAlrawi_1J
Mon Nov 18, 2019 1:37 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bonds in VSEPR
Replies: 11
Views: 108

Re: Bonds in VSEPR

We consider unbonded electron pairs as well as single, double, and triple bonds to just be individual "regions of electron density" for the sake of VSEPR models
by ZainAlrawi_1J
Sun Nov 17, 2019 7:56 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: types of bonds
Replies: 14
Views: 532

Re: types of bonds

Yes, a triple bond has 1 sigma bond and 2 pi bonds.
by ZainAlrawi_1J
Sun Nov 17, 2019 7:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 5
Views: 80

Re: VSEPR

The number of bonding pairs and lone pairs attached to a central atom determines its shape, I would recommend looking up a VSEPR chart as it shows how intuitive it is.
by ZainAlrawi_1J
Sun Nov 17, 2019 7:46 pm
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bonds
Replies: 6
Views: 72

Re: Hydrogen Bonds

Hydrogen atom covalently bonded to Nitrogen, Oxygen, or Fluorine.
by ZainAlrawi_1J
Sun Nov 17, 2019 7:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 19
Views: 277

Re: Test 2

Draw the most stable structure (formal charges in mind) in order to accurately predict the shape
by ZainAlrawi_1J
Sun Nov 10, 2019 4:19 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 4
Views: 72

Re: Polarizability

Polarizability increases toward down and to the left on the periodic table, while polarizing power increases up and to the right on the periodic table.
by ZainAlrawi_1J
Sun Nov 10, 2019 4:17 pm
Forum: Lewis Structures
Topic: Electronegative
Replies: 14
Views: 146

Re: Electronegative

Yes, elements with higher electronegativity are more likely to get electrons as they are closer to reaching a stable configuration.
by ZainAlrawi_1J
Sun Nov 10, 2019 4:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum numbers
Replies: 13
Views: 306

Re: Magnetic Quantum numbers

The magnetic quantum number ranges from the values -l to +l
by ZainAlrawi_1J
Sun Nov 10, 2019 4:14 pm
Forum: Lewis Structures
Topic: Xenon
Replies: 4
Views: 85

Re: Xenon

All elements with access to the d orbital follow the same exception as Xenon as they can hold more electrons because of their access to the orbital.
by ZainAlrawi_1J
Sun Nov 10, 2019 4:14 pm
Forum: Lewis Structures
Topic: Exceptions like Xenon
Replies: 3
Views: 46

Re: Exceptions like Xenon

All elements with access to the d orbital follow the same exception as Xenon.
by ZainAlrawi_1J
Sun Nov 10, 2019 4:13 pm
Forum: Dipole Moments
Topic: Van der Waals
Replies: 2
Views: 29

Re: Van der Waals

For the purposes of the course so far, we don't need to distinguish between them, though it is very good to know this for future courses
by ZainAlrawi_1J
Sun Nov 10, 2019 4:12 pm
Forum: Bond Lengths & Energies
Topic: Strongest Bond
Replies: 15
Views: 168

Re: Strongest Bond

In increasing strength:
Single bonds < Double bonds < Triple bonds.
by ZainAlrawi_1J
Sun Nov 10, 2019 4:11 pm
Forum: General Science Questions
Topic: Extra Credit
Replies: 19
Views: 263

Re: Extra Credit

There's unfortunately no extra credit opportunities for 14A :(
by ZainAlrawi_1J
Sun Nov 10, 2019 4:11 pm
Forum: General Science Questions
Topic: Test 2
Replies: 20
Views: 252

Re: Test 2

The second test will cover content from only after the midterm, check the syllabus for more info.
by ZainAlrawi_1J
Sun Nov 03, 2019 10:57 pm
Forum: Formal Charge and Oxidation Numbers
Topic: How to know where a double bond should go?
Replies: 10
Views: 148

Re: How to know where a double bond should go?

Just sorted it out by doing the formal charges for the atoms in both possible structures, unfortunately had to the formal charges for all the oxygen atoms to get a clear answer but its definitely obvious now. Thanks everyone!
by ZainAlrawi_1J
Sun Nov 03, 2019 10:37 pm
Forum: Formal Charge and Oxidation Numbers
Topic: How to know where a double bond should go?
Replies: 10
Views: 148

How to know where a double bond should go?

As in part (c) of question 2C.5, the double bond is drawn between the O and N atoms, why is this the case? Why isn't it drawn between the Cl and O atoms?
by ZainAlrawi_1J
Sun Nov 03, 2019 10:34 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty in position
Replies: 1
Views: 43

Re: Uncertainty in position

Use the equation ΔpΔx ≥ h/4π

wherein
Δp = momentum, also equal to m*v (mass times velocity)
Δx = position
h = planck's constant
by ZainAlrawi_1J
Sun Nov 03, 2019 10:30 pm
Forum: Octet Exceptions
Topic: Expanded Valence Shells
Replies: 6
Views: 61

Re: Expanded Valence Shells

Elements with d orbitals (period 3 and beyond), can have expanded valence shells.
by ZainAlrawi_1J
Sun Nov 03, 2019 10:28 pm
Forum: Lewis Structures
Topic: Resonance
Replies: 5
Views: 47

Re: Resonance

Resonance describes any lewis structure with more than one way of being drawn without altering the structure of the drawn molecule.
by ZainAlrawi_1J
Sun Nov 03, 2019 10:27 pm
Forum: Electronegativity
Topic: definitions
Replies: 8
Views: 119

Re: definitions

The ionization energy is the amount of energy that is required to remove an electron from an atom, while an atom's electron affinity is the amount of energy released or spent when an electron is added to an atom.
by ZainAlrawi_1J
Sun Nov 03, 2019 10:24 pm
Forum: Electronegativity
Topic: electronegativity trend
Replies: 9
Views: 91

Re: electronegativity trend

It decreases a the distance between the electrons increases further away from the nucleus, as such decreasing their attraction.
by ZainAlrawi_1J
Mon Oct 28, 2019 10:03 pm
Forum: Properties of Light
Topic: Midterm formulas
Replies: 6
Views: 146

Re: Midterm formulas

The formula sheet is available to print out on Lavelle's site.
by ZainAlrawi_1J
Mon Oct 28, 2019 9:56 pm
Forum: Trends in The Periodic Table
Topic: electronegativity table
Replies: 5
Views: 108

Re: electronegativity table

If we need to work with any actual numerical values, then yes, they will be given.
by ZainAlrawi_1J
Mon Oct 28, 2019 9:50 pm
Forum: Electronegativity
Topic: Calculating Electronegativity
Replies: 3
Views: 53

Re: Calculating Electronegativity

We would only have to calculate the differences in electronegativity between already given values, as in we should be provided with either an electronegativity table or the relevant exact figures for a given problem.
by ZainAlrawi_1J
Mon Oct 28, 2019 9:21 pm
Forum: Octet Exceptions
Topic: aufbau principle
Replies: 8
Views: 143

Re: aufbau principle

Base it purely off the number order,
3d is n = 3
4s is n = 4
4 > 3
3 is at a lower energy level
by ZainAlrawi_1J
Mon Oct 28, 2019 1:52 pm
Forum: Ionic & Covalent Bonds
Topic: Delocalized Bond
Replies: 4
Views: 45

Re: Delocalized Bond

Delocalized bonds are not tied down to a single nucleus in the same way localized bonds are. Delocalized bonds occur in every example of resonance bonding, as they contain electrons that are free to move about in the structure and thus allowing different lewis structures to be draw representing the ...
by ZainAlrawi_1J
Mon Oct 28, 2019 1:47 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E #13
Replies: 3
Views: 71

Re: 1E #13

This is an "exception to the exception" that is the Aufbau Principle and I don't think we're quite required to know. There is a more concise explanation on this link: https://socratic.org/questions/57b1630911ef6b4fbd986ed8
by ZainAlrawi_1J
Mon Oct 28, 2019 1:40 pm
Forum: Bond Lengths & Energies
Topic: Electron-Electron Repulsion
Replies: 2
Views: 37

Re: Electron-Electron Repulsion

One proton has a greater affect on radius than one electron, hence why as you go from left to right across a period, atomic radius tends to decrease.
by ZainAlrawi_1J
Mon Oct 28, 2019 1:37 pm
Forum: General Science Questions
Topic: homework
Replies: 5
Views: 89

Re: homework

Any 5 problems off the Chemical Bonds section on the syllabus are fair game
by ZainAlrawi_1J
Mon Oct 28, 2019 1:34 pm
Forum: Ionic & Covalent Bonds
Topic: Ground-State electron configuration
Replies: 3
Views: 52

Re: Ground-State electron configuration

The ground state describes an atom at its lowest possible energy level. An atom is at an excited state when the energy level of its electron is at a higher energy level than its ground state. You can tell them apart by looking at the electron configuration, as any electron configuration in which the...
by ZainAlrawi_1J
Sun Oct 20, 2019 12:17 am
Forum: Properties of Electrons
Topic: Constants given on tests?
Replies: 2
Views: 58

Re: Constants given on tests?

Yes, we'll receive the values and units for all the constants we'd need as we did on the front page of Test #1.
by ZainAlrawi_1J
Sun Oct 20, 2019 12:11 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin up and spin down
Replies: 13
Views: 200

Re: Spin up and spin down

For the purposes of this class we don't need to know much beyond what he went over in lecture about what an electron's spin is. However, you could liken the spin of an electron to a the spinning of our earth, as it goes in a single direction, spins on an axis, and it is a property that describes its...
by ZainAlrawi_1J
Sun Oct 20, 2019 12:06 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron States
Replies: 3
Views: 53

Re: Electron States

Orbitals are not a real part of an atom, it is essentially a mathematical way of computing an atom an electron's wave-like and complex pattern of behavior.
by ZainAlrawi_1J
Sun Oct 20, 2019 12:03 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Which Element to Use in Electron Configurations
Replies: 5
Views: 73

Re: Which Element to Use in Electron Configurations

As far as this class is concerned, always use the noble gas configuration when applicable unless otherwise indicated. It saves a lot of time and is definitely the "proper" way of doing it.
by ZainAlrawi_1J
Sun Oct 20, 2019 12:02 am
Forum: Properties of Electrons
Topic: d vs s orbitals
Replies: 6
Views: 86

Re: d vs s orbitals

For elements that are considered exceptions, you write 4s --> 3d because 4s has less energy, but most of the time it you would just do 3d --> 4s
by ZainAlrawi_1J
Sat Oct 12, 2019 2:54 pm
Forum: DeBroglie Equation
Topic: De Broglie equation
Replies: 5
Views: 42

Re: De Broglie equation

h (plack's constant) is usually given in J*s, which means mass is most simply computed in kilograms, and length in meters as J=kg×m^2
by ZainAlrawi_1J
Sat Oct 12, 2019 2:46 pm
Forum: Properties of Light
Topic: Equations
Replies: 4
Views: 51

Re: Equations

De Broglie does not apply to electromagnetic radiation as it is focused on objects with mass and momentum. All others (that we have learned at least) are EM equations
by ZainAlrawi_1J
Sat Oct 12, 2019 2:44 pm
Forum: Significant Figures
Topic: Significant Figures and Molar Masses
Replies: 5
Views: 214

Re: Significant Figures and Molar Masses

No, do not use molar masses as part of figuring out how many significant figures should be used. Only use given usable values in the equation.
by ZainAlrawi_1J
Sat Oct 12, 2019 2:42 pm
Forum: DeBroglie Equation
Topic: De Broglie's Equation
Replies: 13
Views: 154

Re: De Broglie's Equation

The De Broglie equation is used to describe the wave properties of matter, and as such the equation is reserved for things that have mass, such as electrons. In practice, De Broglie is used when we are solving for an object's wavelength, and it has mass. This is in contrast to what you would use whe...
by ZainAlrawi_1J
Sat Oct 12, 2019 2:39 pm
Forum: Limiting Reactant Calculations
Topic: Wrong calculation-can' find the Lim. Reactant
Replies: 2
Views: 153

Re: Wrong calculation-can' find the Lim. Reactant

Since you have 1.26 moles of NH3 and 1.33 mol of O2, then you can already deduce that NH3 is the limiting reactant. You can now use the mole ratio of 4 NH3 for every 4 NO molecules to deduce how many grams of NO are produced, and then use the same process to figure out how many grams of H2O, by usin...
by ZainAlrawi_1J
Wed Oct 02, 2019 3:16 pm
Forum: Significant Figures
Topic: Sig Fig Decimal
Replies: 10
Views: 135

Re: Sig Fig Decimal

114 and 114. have the same number of sig figs.
114 and 114.0 do not have the same number of sig figs.

114 has 3 significant figures.
114.0 has 4 significant figures.
by ZainAlrawi_1J
Wed Oct 02, 2019 2:01 pm
Forum: Molarity, Solutions, Dilutions
Topic: Please clarify what M means
Replies: 5
Views: 90

Re: Please clarify what M means

Capital M denotes molarity, which is moles of solute per liter of solution.
by ZainAlrawi_1J
Wed Oct 02, 2019 1:52 pm
Forum: Empirical & Molecular Formulas
Topic: Homework problem E1
Replies: 9
Views: 160

Re: Homework problem E1

E1. Step 1: 1 mol Ag * (6.022*10^23 Ag atoms / 1 mol Ag) = 6.022*10^23 atoms of Ag Step 2: Multiply 144 by 2 to get 288 (convert radius to diameter), and then multiply by the number of atoms of Ag. --> 288 * 6.022*10^23 = 1.73*10^26pm Step 3: Convert our answer from picometers (pm) to meters (m). --...
by ZainAlrawi_1J
Wed Oct 02, 2019 1:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: How do I do problem E.3 on page F45 of the textbook?
Replies: 4
Views: 120

Re: How do I do problem E.3 on page F45 of the textbook?

The question is written confusingly but has a rather straight forward answer, it is more logic-based than it is chemistry. You have 9 atoms of Gallium at 70g/mol (total of 9 * 70 = 630). You want to figure out how many atoms of Astatine, which is given as 210 g/mol, would be equal to this. Therefore...
by ZainAlrawi_1J
Tue Oct 01, 2019 6:26 pm
Forum: Empirical & Molecular Formulas
Topic: E.25 Parts (b) & (c)
Replies: 2
Views: 48

E.25 Parts (b) & (c)

For some reason I can't seem to get the same answers as the textbook, anyone care to do a step by step? E.25 (a) Determine the number of KNO 3 formula units in 0.750 mol KNO 3. (b) What is the mass (in milligrams) of 2.39 ? 10 20 formula units of Ag2SO4? (c) Estimate the number of NaHCO 2 formula un...
by ZainAlrawi_1J
Tue Oct 01, 2019 3:25 pm
Forum: Limiting Reactant Calculations
Topic: Question on E9
Replies: 4
Views: 51

Re: Question on E9

In order to find out how many atoms of oxygen are in 5.15 g of Epsom salts we have to find out how many moles of magnesium sulfare heptahydrate (246.48 g/mol) are present in the sample. O = (5.15 g / 246.48 g/mol) * (11 mol O-atoms/1 mol MgSO4·7H2O) * (6.022x10^23 atoms/mol) = 1.38 x 10^23 atoms of ...

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