Search found 30 matches

by NabilaNizam-1K
Fri Jun 08, 2018 1:34 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating the difference between two pH values
Replies: 2
Views: 155

Re: Calculating the difference between two pH values

I think you are trying to calculate the strength of the same type of acid (eg: HCl) before and after dilution. Since pH value is affected by the [H+], calculating the concentration of H+ in both solutions can give you the pH value by using

pH = -log[H+]
by NabilaNizam-1K
Fri Jun 08, 2018 1:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Charge of ligands
Replies: 5
Views: 139

Charge of ligands

Since there is a large number of ligands that form coordination compounds with metallic atoms, do we have to memorize the charges of these ligands or is it more beneficial to determine the charge using Lewis structure?
by NabilaNizam-1K
Thu May 31, 2018 4:51 pm
Forum: Hybridization
Topic: How to identify pi and sigma bonds
Replies: 4
Views: 90

Re: How to identify pi and sigma bonds

It is important to remember that the sigma bond will always form first, followed by the pi bonds. In the formation of multiple bonds, there will always be ONE sigma bond followed by 1 or 2 pi bonds.
by NabilaNizam-1K
Thu May 31, 2018 4:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Define Ligands?
Replies: 10
Views: 237

Re: Define Ligands?

Do we only classify certain molecules as ligands when it is involved in the formation of an organometallic complex?
by NabilaNizam-1K
Thu May 31, 2018 4:26 pm
Forum: Sigma & Pi Bonds
Topic: Double bond with 2 pi bonds?
Replies: 2
Views: 150

Re: Double bond with 2 pi bonds?

A sigma bond will always be formed first during the formation of a double bond so a double bond with 2 pi bonds is highly unlikely.
by NabilaNizam-1K
Thu May 31, 2018 4:19 pm
Forum: Hybridization
Topic: sp^3 orbitals
Replies: 3
Views: 84

Re: sp^3 orbitals

Hi Adrienne,

I think instead of unfilled sp3 orbitals, it should be unpaired electron in sp3 orbitals that form σ-bonds since empty orbitals are not able to form any bonds with other atoms
by NabilaNizam-1K
Wed May 23, 2018 9:20 pm
Forum: Lewis Structures
Topic: 3.35
Replies: 1
Views: 85

Re: 3.35

Ionic compounds can be made up of covalent bonds, and will only form ionic bonds when the compounds are bonded to another ionic compound.
by NabilaNizam-1K
Wed May 23, 2018 7:57 pm
Forum: Lewis Structures
Topic: Finding the central element on the Lewis structure
Replies: 4
Views: 160

Re: Finding the central element on the Lewis structure

Does this mean if the compound is made up of group 1 or 2 elements and the FONCl elements, the metal elements will always be the central element?
by NabilaNizam-1K
Fri May 18, 2018 11:51 am
Forum: Ionic & Covalent Bonds
Topic: Solubility
Replies: 3
Views: 64

Re: Solubility

Compounds with covalent bond do not dissolve but dissolve in other organic solvents. Ionic compounds dissolve in water as the ions dissociate in the presence of H+ and OH- ions in water
by NabilaNizam-1K
Fri May 18, 2018 11:47 am
Forum: Dipole Moments
Topic: Defining "Distortion"
Replies: 1
Views: 125

Re: Defining "Distortion"

Polarizing power refers to the ability of a cation to distort the electron cloud of the anion in an ionic compound. The electron cloud of an anion is pulled towards the cation when it is distorted, giving the ionic bond a covalent character. If the polarization is quite small, an ionic bond is forme...
by NabilaNizam-1K
Wed May 16, 2018 12:33 pm
Forum: Lewis Structures
Topic: formal charge on central atom
Replies: 3
Views: 111

Re: formal charge on central atom

Does the formal charge of the central atom affect the overall charge of the molecule?
by NabilaNizam-1K
Wed May 16, 2018 12:31 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis Acids and Bases
Replies: 4
Views: 111

Re: Lewis Acids and Bases

In order to determine the strength (bond strength) of an acid, it depends on the size of the 'A' atom: the smaller the 'A' atom, the stronger the H-A bond. When going down a row in the Periodic Table, the atoms get larger so the strength of the bonds get weaker, which means the acids get stronger. F...
by NabilaNizam-1K
Thu May 10, 2018 8:15 pm
Forum: Ionic & Covalent Bonds
Topic: Difference between anions and cations?
Replies: 3
Views: 90

Re: Difference between anions and cations?

Anions: when an atom gains electrons and form a negatively charged ion due to the increased number of electron
Cations: when an atom loses electrons and form a positively charged ion due to the decreased number of electron

This is basically how I remember it so I hope it helps!
by NabilaNizam-1K
Thu May 10, 2018 8:06 pm
Forum: Ionic & Covalent Bonds
Topic: Octet
Replies: 7
Views: 236

Re: Octet

Since the first four elements will not achieve octet, is there a special term for the condition when these elements achieve stable state and all the orbitals are filled?
by NabilaNizam-1K
Wed May 09, 2018 4:09 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Topics [ENDORSED]
Replies: 33
Views: 1586

Re: Midterm [ENDORSED]

Maldonado3K wrote:Hello there, I am overthinking everything.. but just to confirm.. our midterm is taking place in CS50 correct? Thanks!


It depends on your last name
A-F at CS24
G-N at Franz 1178
O-Z at CS76

Hope this helps!
by NabilaNizam-1K
Wed May 09, 2018 11:02 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: q16
Replies: 2
Views: 129

Re: q16

hi can you clarify which question 16 because I would love to help!
by NabilaNizam-1K
Sat May 05, 2018 3:07 pm
Forum: Trends in The Periodic Table
Topic: Ionic radius trend
Replies: 2
Views: 65

Re: Ionic radius trend

During the formation of a cation, electrons are lost from their shells and since the radius is directly affected by the number of shells, this causes the ion to possess less number of shells than their parent atom, hence they are smaller. Meanwhile, during the formation of an anion, electrons are ga...
by NabilaNizam-1K
Sat May 05, 2018 2:45 pm
Forum: Limiting Reactant Calculations
Topic: Homework M12
Replies: 3
Views: 188

Re: Homework M12

Based on the calculations, we can find the masses of the products, Fe and Al_2O_3 which are 4.907g and 4.4814 g respectively. Therefore, the mass of excess reactant leftover can be calculated by subtracting the total mass of products from the initial total mass of reactants. Mass of excess reactants...
by NabilaNizam-1K
Sat May 05, 2018 2:07 pm
Forum: Balancing Chemical Reactions
Topic: Test 1 Q3
Replies: 2
Views: 148

Re: Test 1 Q3

Answer:

Usually, for balancing equation questions, I try balancing the least abundant element first which is Cu in this case. Hope this helps!
by NabilaNizam-1K
Fri Apr 27, 2018 1:19 pm
Forum: Properties of Light
Topic: Energy difference in excited electrons
Replies: 3
Views: 99

Energy difference in excited electrons

I understand that we can use the Rydberg equation to calculate the energy change when electrons are excited from one energy level to another. But what should we do when the values of n are not given? Do we use the Lyman and Balmer series value of n1 as the original value of n?
by NabilaNizam-1K
Fri Apr 27, 2018 1:05 pm
Forum: Balancing Chemical Reactions
Topic: balancing chemical reactions
Replies: 6
Views: 245

Re: balancing chemical reactions

Cu + 4HNO3 --> Cu(NO3)2 + 2NO + 2 H2O
by NabilaNizam-1K
Thu Apr 26, 2018 4:47 pm
Forum: Quantum Numbers and The H-Atom
Topic: higher energy/ lower energy
Replies: 2
Views: 91

Re: higher energy/ lower energy

S, p, d and f are orbitals for the electrons. Electrons in s orbital has lower energy as it is the smallest orbital and this the energy of the electrons increases when it is in larger orbitals. Size of orbital: s<p<d<f.
by NabilaNizam-1K
Fri Apr 20, 2018 1:37 pm
Forum: Photoelectric Effect
Topic: Threshold Energy [ENDORSED]
Replies: 12
Views: 297

Re: Threshold Energy [ENDORSED]

What affects the threshold energy of a photon?
by NabilaNizam-1K
Fri Apr 20, 2018 1:34 pm
Forum: Photoelectric Effect
Topic: Post-Assessment #31 [ENDORSED]
Replies: 2
Views: 110

Re: Post-Assessment #31 [ENDORSED]

If you are calculating the kinetic energy of the ejected electron, you can use the equation
where m=mass of an electron and v=velocity of the electron after it's ejected
by NabilaNizam-1K
Fri Apr 20, 2018 1:28 pm
Forum: Properties of Light
Topic: Wavelengths
Replies: 8
Views: 203

Re: Wavelengths

I think it also helps if we know the order of frequency of the electromagnetic waves, which is the inverse of the wavelength order.
by NabilaNizam-1K
Thu Apr 19, 2018 3:56 pm
Forum: Properties of Electrons
Topic: Geiger -Marsden experiment [ENDORSED]
Replies: 5
Views: 150

Re: Geiger -Marsden experiment [ENDORSED]

Do we have to study the experiment in detail or do we just have to know the concepts and result of the experiment?
by NabilaNizam-1K
Thu Apr 12, 2018 4:50 pm
Forum: Molarity, Solutions, Dilutions
Topic: When to use MiVi=MfVf
Replies: 8
Views: 310

Re: When to use MiVi=MfVf

Hello, I'm having some difficulty determining when to use the M(initial) x V(initial) = M(final) x V(final) equation in problems. Is there any way to know to use this equation in a type of problem? What kind of problems is it used for? Thanks! You can use this equation to find either molarity/conce...
by NabilaNizam-1K
Thu Apr 12, 2018 4:41 pm
Forum: Properties of Electrons
Topic: Electromagnetic Field [ENDORSED]
Replies: 7
Views: 199

Re: Electromagnetic Field [ENDORSED]

I think the direction of the waves can be interchangeable as long as they are drawn perpendicular to each other.
by NabilaNizam-1K
Thu Apr 12, 2018 4:39 pm
Forum: SI Units, Unit Conversions
Topic: Sig Figs
Replies: 9
Views: 302

Re: Sig Figs

In case of calculations that require the usage of values from the periodic table, are we supposed to use the exact value stated or should we round it up?
by NabilaNizam-1K
Sat Apr 07, 2018 8:58 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 90
Views: 7834

Re: All students read this sig fig post [ENDORSED]

I am wondering how many sig figs are we supposed to round off our answer to after getting the value from a calculator?

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