Search found 66 matches

by Sandy Lin 1L
Sun Jan 24, 2021 5:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium concentrations for acids
Replies: 3
Views: 11

Re: Equilibrium concentrations for acids

Yes, you would have to use Ka. If you were given Kb when you are solving for an acid, make sure you use that value to find the Ka using the formula (Ka)(Kb) = 10^-14
by Sandy Lin 1L
Sun Jan 24, 2021 1:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Friday Lecture Question
Replies: 1
Views: 10

Re: Friday Lecture Question

It has to be converted from a liquid to gas because the table of bond enthalpies refers to breaking bonds in gases; therefore, you would need to add the enthalpy of phase change when something is in the liquid or solid phase.
by Sandy Lin 1L
Sun Jan 24, 2021 1:19 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: When enthalpy is zero
Replies: 4
Views: 18

Re: When enthalpy is zero

Since it is the most stable state, the formation would not require any energy as compounds like O2 form naturally.
by Sandy Lin 1L
Sat Jan 23, 2021 5:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Do concentrations change at equilibrium?
Replies: 9
Views: 38

Re: Do concentrations change at equilibrium?

Since the rates of the reactions are equal, the concentrations of the products and reactants at equilibrium should not be changing and are constant at equilibrium.
by Sandy Lin 1L
Sat Jan 23, 2021 5:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong vs. weak acids and bases
Replies: 3
Views: 13

Re: Strong vs. weak acids and bases

I think it will be easier just to memorize the strong acids and bases since there are not a lot of them. All of the other acids and bases that are not strong can be considered weak.
by Sandy Lin 1L
Sun Jan 17, 2021 1:15 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q > K, Q< K
Replies: 25
Views: 75

Re: Q > K, Q< K

K is calculated when the reaction is at equilibrium that is why it is a constant and will not change. Q can be calculated at any time during the reaction. The value of Q is compared with K to show which direction the reaction will proceed or if the reaction is at equilibrium. When Q>K then there are...
by Sandy Lin 1L
Sat Jan 16, 2021 11:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ka vs kb
Replies: 20
Views: 60

Re: ka vs kb

Ka is the acidity constant and is found when calculating the equilibrium constant for weak acids. Kb (basicity constant) is the same thing but just for weak bases.
by Sandy Lin 1L
Sat Jan 16, 2021 11:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka x Kb
Replies: 11
Views: 33

Re: Ka x Kb

In the autoprotolysis of water, the concentrations of H3O+ and OH- are both 1.0 X 10^-7. When these values are multiplied, you get 10^-14.
by Sandy Lin 1L
Sat Jan 16, 2021 10:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box
Replies: 5
Views: 27

Re: ICE Box

To use the ICE box you would need the balanced chemical equation, and ICE corresponds to initial molar concentration, change in molar concentration, and equilibrium molar concentration. For the initial values, you should be given some information about the concentrations. If you were given the initi...
by Sandy Lin 1L
Sat Jan 16, 2021 9:18 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Autoprotolysis
Replies: 6
Views: 36

Re: Autoprotolysis

Autoprotolysis is a reaction that occurs when a proton is transferred between two identical molecules. This reaction can occur in amphiprotic (proton acceptor and donor) solvents like water.
by Sandy Lin 1L
Sun Jan 10, 2021 8:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K values
Replies: 4
Views: 25

Re: K values

When the value of the equilibrium constant is between these values, it means that neither the reactants nor the products are strongly favored.
by Sandy Lin 1L
Sun Jan 10, 2021 3:14 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient Definition
Replies: 7
Views: 23

Re: Reaction Quotient Definition

The difference between Q and K is that K is the equilibrium constant, so it is calculated when the system is at equilibrium. Q, the reaction quotient is found during any stage of the reaction. They are calculated by the same equation, and this is why when you compare the two values, you can determin...
by Sandy Lin 1L
Sun Jan 10, 2021 9:37 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Response of Equilibria to Change
Replies: 8
Views: 23

Re: Response of Equilibria to Change

The actual value of the equilibrium constant changes only due to a response in a change in temperature. Other factors will only potentially cause a shift in the position of equilibrium.
by Sandy Lin 1L
Sun Jan 10, 2021 9:33 am
Forum: Ideal Gases
Topic: PV=nRT and concentration
Replies: 27
Views: 117

Re: PV=nRT and concentration

Concentration refers to the amount of a substance in a solvent. This is why it is calculated by the number of moles of the substance divided by the volume. You would use this when you want to convert between Kp and Kc. If you’re ever confused it’s good to know the units that are involved in the calc...
by Sandy Lin 1L
Tue Jan 05, 2021 8:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium is shifted to the right/left
Replies: 9
Views: 37

Re: Equilibrium is shifted to the right/left

From the questions in the module, equilibrium is shifted to the right when K>1 whereas equilibrium is shifted to the left when K<1. This is because the equilibrium constant, K, refers to the relationship between product and reactant. Since products are in the numerator, when there are more products ...
by Sandy Lin 1L
Sat Dec 12, 2020 6:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Protonation
Replies: 4
Views: 37

Re: Protonation

By the Bronsted Lowry definition, an acid donates a proton. This action is the acid deprotonating as it loses the proton. The Bronsted Lowry base will accept a proton from the acid, so it protonates.
by Sandy Lin 1L
Sat Dec 12, 2020 5:13 pm
Forum: Bronsted Acids & Bases
Topic: metal/nonmetal oxides
Replies: 3
Views: 20

Re: metal/nonmetal oxides

Know that metal oxides form basic oxides whereas nonmetal oxides form acidic oxides. You should also remember which form amphoteric oxides.
by Sandy Lin 1L
Sat Dec 12, 2020 12:48 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculation OH- sapling
Replies: 4
Views: 22

Re: Calculation OH- sapling

You can use the concentration of H+ given to calculate the pH by taking the negative log of the value. Then to find the pOH you take 14 minus the pH value found. To find the OH- concentration, you would just take 10 to the power of negative -pOH.
by Sandy Lin 1L
Fri Dec 11, 2020 4:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Does en contriubiute to the coordination number twice?
Replies: 2
Views: 16

Re: Does en contriubiute to the coordination number twice?

en represents the neutral ligand ethylenediamine, and this ligand is a bidentate ligand. This means that it will contribute 2 to the coordination number, and it has two sites where it will bond to the transition metal.
by Sandy Lin 1L
Fri Dec 11, 2020 4:37 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Ligands vs Polydentate ligands
Replies: 5
Views: 35

Re: Chelating Ligands vs Polydentate ligands

Ligands can be classified by how many times they bond with the transition metal. If it only forms one bond then it is monodentate. If it forms more than one bond, it is polydentate. Since it bonds more than once, it will form a chelate/ring of atoms.
by Sandy Lin 1L
Sun Dec 06, 2020 8:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Week 9 HW #5
Replies: 5
Views: 25

Re: Sapling Week 9 HW #5

The coordination number should be six since en is bidentate so it bonds twice and there are two so that is four. You then have the two CO, so altogether there are six bonded to the TM.
by Sandy Lin 1L
Sun Dec 06, 2020 12:44 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH and pOH
Replies: 6
Views: 45

Re: pH and pOH

pH is used to define the concentration of H3O+ whereas pOH is used to define the concentration of OH-. For both, you take the -log of the concentration of the ions.
by Sandy Lin 1L
Sun Dec 06, 2020 12:36 pm
Forum: Dipole Moments
Topic: Dipole canceling
Replies: 13
Views: 81

Re: Dipole canceling

Yes, a nonpolar molecule can have polar bonds along with nonpolar bonds, but the polar bonds have dipoles that cancel out so that overall, the molecule has zero dipole moment.
by Sandy Lin 1L
Sun Dec 06, 2020 12:28 pm
Forum: Lewis Acids & Bases
Topic: Acids question
Replies: 4
Views: 31

Re: Acids question

This formula is used to calculate concentrations of weak acids by setting up an equilibrium. This is only used for weak acids because they are not completely ionized in the solution, unlike strong acids.
by Sandy Lin 1L
Sun Dec 06, 2020 12:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand names
Replies: 6
Views: 46

Re: Ligand names

For the anions, they follow a pattern where they will end in -o (or -ido) most of the time. This ending is used to show that the ligand is directly bounded to the transition metal. A prefix is used to indicate the number of ligands, and they should be written in alphabetical order. For many of the l...
by Sandy Lin 1L
Sun Dec 06, 2020 12:11 pm
Forum: Naming
Topic: Naming H2O
Replies: 11
Views: 90

Re: Naming H2O

I do not think it matters since both still represent a water molecule. The reason why they are written in different orders is that it represents which atom is bonded to the central atom. In the case of H20, since hydrogen can only form one bond, and it is already bonded to Oxygen, only the oxygen ca...
by Sandy Lin 1L
Sun Nov 29, 2020 12:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw and T-shapes
Replies: 4
Views: 47

Re: Seesaw and T-shapes

Both seesaw and t-shaped molecules have five regions of electron density. The difference between them is that a seesaw shaped molecule has one lone pair and four bonded pairs. The VSEPR formula of a seesaw shaped molecule is AX4E. For a t-shaped molecule, the formula is AX3E2; there are two lone pai...
by Sandy Lin 1L
Sun Nov 29, 2020 12:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Methane vs ammonia
Replies: 5
Views: 31

Re: Methane vs ammonia

Even though the two molecules both have 4 regions of electron density they are still different shapes due to one of the regions on ammonia being a lone pair of electrons. This lone pair causes repulsion because it is not bonded pushing the other atoms closer together resulting in the trigonal pyrami...
by Sandy Lin 1L
Sat Nov 28, 2020 6:46 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Sapling Q.20
Replies: 7
Views: 53

Re: Sapling Q.20

You can tell whether a molecule is polar or not by looking at the lewis structure. Since you know that the molecular shape is tetrahedral and that all the atoms surrounding the central atom (As) are all the same, the molecule overall is nonpolar because the dipoles in the polar As and O bonds will c...
by Sandy Lin 1L
Sat Nov 28, 2020 2:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity and Shape
Replies: 13
Views: 93

Re: Polarity and Shape

You would have to draw it out to see if the dipoles cancel out. Both polar and nonpolar molecules can have polar bonds, but the difference is that in nonpolar molecules, you can see that the dipoles will cancel in the polar bonds pulling in opposite directions when you draw it.
by Sandy Lin 1L
Sat Nov 28, 2020 1:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Wk8 Q. 18, Determining Molecular Shape
Replies: 10
Views: 70

Re: Sapling Wk8 Q. 18, Determining Molecular Shape

Yes, most of the time, the way the molecular formula is written indicates which atoms are bonded together. Especially when the same atoms are written out instead of just using a subscript to show how many of the atom there are.
by Sandy Lin 1L
Sun Nov 22, 2020 7:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: BOND ANGLES FOR CERTAIN MOLECULAR SHAPES
Replies: 4
Views: 37

Re: BOND ANGLES FOR CERTAIN MOLECULAR SHAPES

You can't really calculate most bond angles as they have to be experimentally determined. All you can do is compare some bond angles such as looking at how many bonding pairs there are and how many lone pairs there are. For example, in a tetrahedral and in a trigonal pyramidal, there are 4 regions o...
by Sandy Lin 1L
Sun Nov 22, 2020 6:03 pm
Forum: Lewis Structures
Topic: # of electrons in expanded valence
Replies: 6
Views: 53

Re: # of electrons in expanded valence

Since it is asking you about an expanded valence, you automatically know that the number of electrons it is asking for is greater than 8, the size of a normal octet. Therefore, you should also count the shared electrons.
by Sandy Lin 1L
Sun Nov 22, 2020 5:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Planar vs Angular
Replies: 1
Views: 19

Re: Trigonal Planar vs Angular

I think the electron arrangement being trigonal planar is because there are 3 regions of electron density (the two bonds and the unbonded electron). The shape would actually be angular because only two of them are bonded, and the extra electron bends the shape due to electron repulsion.
by Sandy Lin 1L
Sun Nov 22, 2020 2:39 pm
Forum: Trends in The Periodic Table
Topic: Ionic Character
Replies: 11
Views: 93

Re: Ionic Character

Ionic character is determined by the partial charges that form between atoms that are bonded together; the more electronegative element will pull the electron towards itself making it slightly negative. This is ionic character because one atom is trying to take the electrons more and not wanting to ...
by Sandy Lin 1L
Sun Nov 22, 2020 2:34 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Dispersion
Replies: 33
Views: 165

Re: London Dispersion

Yes LDF occurs in all molecules because the electron clouds of atoms are always changing when atoms interact.
by Sandy Lin 1L
Sun Nov 15, 2020 11:48 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.21 (omit c)
Replies: 3
Views: 34

Re: 1E.21 (omit c)

In Bi, there 3 unpaired electrons because on the periodic table it is in the third column of the p block which has 3 orbitals (according to Hund's rule each orbital must have one electron before you can add a second). In Si, there are 2 unpaired electrons because it is in the second column of the p ...
by Sandy Lin 1L
Sun Nov 15, 2020 10:43 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: electrons changing subshells
Replies: 2
Views: 13

Re: electrons changing subshells

Metals like copper and chromium take an electron in the d orbital that is expected to fill the s orbital because when d is half full or completely full it is more stable. So in the case of copper, instead of the expected configuration ending with 4s^2 3d^9, it becomes 3d^10 4s^1.
by Sandy Lin 1L
Sun Nov 15, 2020 8:43 am
Forum: Ionic & Covalent Bonds
Topic: Delta Negative and Positive
Replies: 3
Views: 19

Re: Delta Negative and Positive

Whenever there are two atoms that covalently bonded, and the atoms are not the same, the electron pair in the bond is not shared equally. The electrons will be pulled towards the more electronegative atom because electronegativity is the electron pulling power of an atom. These are the elements in t...
by Sandy Lin 1L
Sun Nov 15, 2020 8:35 am
Forum: Octet Exceptions
Topic: Identifying Radicals
Replies: 24
Views: 176

Re: Identifying Radicals

Usually, when you count up the valence electrons and there is an odd number you will have a radical. You can see this when you draw out the lewis structure and there is a single unpaired electron represented by a dot.
by Sandy Lin 1L
Sun Nov 15, 2020 8:33 am
Forum: Trends in The Periodic Table
Topic: Question about Relationship Between Zeff, Atomic Radius, and Ionization Energy
Replies: 2
Views: 26

Re: Question about Relationship Between Zeff, Atomic Radius, and Ionization Energy

Zeff is the effective nuclear charge. As you go down the periodic table, there are more electrons in different shells, that is why the radius will increase. Since the electrons are now further away from the nucleus the effective nuclear charge will decrease. When going across the periodic table, eve...
by Sandy Lin 1L
Sun Nov 08, 2020 8:12 am
Forum: Lewis Structures
Topic: Radicals
Replies: 9
Views: 91

Re: Radicals

Radicals are compounds that have electrons with unpaired spins, and it is an exception to the octet guideline. Because of this unpaired electron, the compound becomes highly reactive and unstable. When you draw the lewis structure, and there is an odd number of electrons, one of the electrons will ...
by Sandy Lin 1L
Sun Nov 08, 2020 8:00 am
Forum: Ionic & Covalent Bonds
Topic: atomic radius
Replies: 7
Views: 49

Re: atomic radius

Atomic radius is just the measurement of half the distance of the nuclei between two of the same atoms that are touching. It is measured using two atoms because it is hard to measure the radius of one atom as the electron clouds do not have distinct boundaries.
by Sandy Lin 1L
Sun Nov 08, 2020 7:54 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 3
Views: 16

Re: Polarizable

When a highly charged cation has the ability to distort the electron cloud of an anion, this process is known as polarization. Highly distorted electrons are described as highly polarizable. When atoms and ions have electron clouds that undergo large distortion, they have highly polarizing power.
by Sandy Lin 1L
Thu Nov 05, 2020 11:26 am
Forum: Lewis Structures
Topic: Radicals
Replies: 9
Views: 91

Re: Radicals

Radicals are compounds that have electrons with unpaired spins, and it is an exception to the octet guideline. Because of this unpaired electron, the compound becomes highly reactive and unstable. When you draw the lewis structure, and there is an odd number of electrons, one of the electrons will r...
by Sandy Lin 1L
Tue Nov 03, 2020 10:07 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 5
Views: 28

Re: Ionization Energy

The farther away from the nucleus an electron is, the easier it is to be removed. Ionization energy refers to the energy required to remove an electron from an atom, so once, the first electron is removed from the neutral atom, the second electron is held on more tightly by the nucleus. The energy r...
by Sandy Lin 1L
Sun Nov 01, 2020 1:25 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Sapling #24
Replies: 16
Views: 73

Re: Sapling #24

Just make sure the ending and the beginning of the wave would connect when you wrap it around in a circular shape. This is because an electron is described as having a circular standing wave around the nucleus.
by Sandy Lin 1L
Sun Nov 01, 2020 12:08 pm
Forum: Trends in The Periodic Table
Topic: Sapling Weeks 2,3,4 Homework #18
Replies: 4
Views: 35

Re: Sapling Weeks 2,3,4 Homework #18

Basically, the cations are smaller than their parent atoms and anions are larger than their parent atoms. To order them by ionic radius, the ones that gain more electrons from their neutral states will have a larger radius because of additional shells added for the electrons.
by Sandy Lin 1L
Sun Nov 01, 2020 11:55 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 30
Views: 421

Re: Atomic Radius

The atomic radius will increase as you go down a group because there are additional shells that are farther from the nucleus. The reason why it will decrease across a period is that even though there might be more electrons, those electrons are in the same shell. An increase in the nuclear charge wi...
by Sandy Lin 1L
Sat Oct 31, 2020 1:37 pm
Forum: Properties of Light
Topic: Relationship between wavelength and frequency
Replies: 10
Views: 91

Re: Relationship between wavelength and frequency

The relationship between wavelength and frequency is that they are inversely proportional so it is not necessarily the same amount. You can observe this from the equation speed of light = wavelength times frequency. If one increases, the other one will decrease.
by Sandy Lin 1L
Fri Oct 30, 2020 6:58 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Plane Importance
Replies: 9
Views: 50

Re: Nodal Plane Importance

Nodal planes allow us to understand the different types of orbitals and why they have certain shapes. The number of nodal planes varies for different orbitals (s has none, p has one, d has two, f has three). In the case of the s orbital, you know there are no nodal planes because the probability of ...
by Sandy Lin 1L
Sun Oct 25, 2020 8:02 am
Forum: *Shrodinger Equation
Topic: Schrodinger on MT
Replies: 7
Views: 89

Re: Schrodinger on MT

I think if we do have questions related to Shrodinger's it would mostly just be conceptual.
by Sandy Lin 1L
Sat Oct 24, 2020 9:47 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Problem 1A.15
Replies: 2
Views: 24

Re: Homework Problem 1A.15

From the problem, you know that the value of the final energy level is 1 because the ultraviolet spectrum correlates with the lyman series. It also states that it is the emission of energy so it is traveling down. After that, you can calculate the energy of the final with E= -hR/n^2. This value subt...
by Sandy Lin 1L
Thu Oct 22, 2020 10:58 am
Forum: Properties of Light
Topic: Specifics on Light
Replies: 5
Views: 59

Re: Specifics on Light

yes, we should def know the order, and it is most important to know that visible light ranges from 700nm to 400nm. For the other ones, it's good to know the approximate ranges too just in case it asks you where it falls on the spectrum.
by Sandy Lin 1L
Wed Oct 21, 2020 10:34 am
Forum: Properties of Light
Topic: Homework Problem 3
Replies: 4
Views: 42

Re: Homework Problem 3

This problem is conceptual. The wavelength and the frequency are both properties of each individual proton, so the amount does not matter as these properties will stay the same. The energy, however, is proportional to the number of photons, so increasing the value will affect it.
by Sandy Lin 1L
Wed Oct 21, 2020 10:06 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Final vs Initial State
Replies: 4
Views: 40

Re: Final vs Initial State

It would depend on the context of the problem as you would have to determine which energy level it is traveling from and where it is traveling to. It would be the final energy level minus the initial energy level. When calculating this, I like to use the E=-hR/n^2 equation instead so I'm not confuse...
by Sandy Lin 1L
Fri Oct 16, 2020 1:10 pm
Forum: Properties of Light
Topic: first worked example
Replies: 3
Views: 43

Re: first worked example

The 16 and 4 come from the values of n being squared as it was n=2 and n=4 in the problem. They are negative and in the denominator because of the equation that was being used: E= -(hr)/(n^2)
by Sandy Lin 1L
Fri Oct 16, 2020 10:05 am
Forum: Properties of Electrons
Topic: Lyman vs. Balmer series
Replies: 20
Views: 164

Re: Lyman vs. Balmer series

The Lyman series is the transition of an electron to the ground state (n=1). This corresponds to the UV region because of the large delta E value between n=2 and n=1. The larger ΔE is, the higher the frequency; the UV region has a higher frequency. The Balmer series is the transition of an electron ...
by Sandy Lin 1L
Wed Oct 14, 2020 11:29 am
Forum: Properties of Light
Topic: 1st worked example in lecture
Replies: 4
Views: 26

Re: 1st worked example in lecture

h is planck's constant and it is 6.626 x 10^-34 Js. c is the speed of light which is 3.00 x 10^8 m/s. I think both of these values will be given.
by Sandy Lin 1L
Tue Oct 13, 2020 9:59 am
Forum: Properties of Electrons
Topic: keV
Replies: 4
Views: 26

Re: keV

keV is a kiloelectron volt. Usually, you would have to convert this to Joules when solving a problem.
by Sandy Lin 1L
Mon Oct 12, 2020 11:03 am
Forum: Properties of Light
Topic: Light Intensity
Replies: 7
Views: 54

Re: Light Intensity

Yes, that is correct. Since the interaction between photons and electrons is one on one, increasing the intensity will not affect whether or not the electrons would be ejected as only the number of photons is increased. In order for electrons to be ejected, it depends on the energy of the individual...
by Sandy Lin 1L
Wed Oct 07, 2020 11:44 am
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G5
Replies: 4
Views: 77

Re: Fundamentals G5

First I would convert all the units to L, mol, and g just to make it easier to solve for the different values. You are given the mass of 2.111g and you need to find the number of moles of the sodium carbonate because concentration is moles over volume. To find the number of moles you have to calcula...
by Sandy Lin 1L
Wed Oct 07, 2020 11:08 am
Forum: Molarity, Solutions, Dilutions
Topic: G. 23
Replies: 5
Views: 58

Re: G. 23

Since you already have the molarity for the chloride ions in each solution, all you have to do is add them together in order to find the total value. The glucose portion is not important because it does not contain chloride ions, which is what you're focusing on.
by Sandy Lin 1L
Wed Oct 07, 2020 9:49 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Review of Chemical and Physical Principles Fundamentals E.15
Replies: 7
Views: 44

Re: Review of Chemical and Physical Principles Fundamentals E.15

For this question, it is asking you what would the sulfide of this metal be if it had one. To solve it you would first need to figure out what element the metal (M) is. Then use that information to calculate the molar mass of the metal sulfide (MS).
by Sandy Lin 1L
Mon Oct 05, 2020 11:04 am
Forum: Balancing Chemical Reactions
Topic: Law of Conservation?
Replies: 16
Views: 150

Re: Law of Conservation?

Law of Conservation is the idea that the total mass is the same before and after. This leads to the amount of atoms having to be the same values in order to add up to equal masses. The moles are only used in order to balance/adjust the number of atoms so they do not have to be equal as long as the m...
by Sandy Lin 1L
Mon Oct 05, 2020 10:54 am
Forum: Molarity, Solutions, Dilutions
Topic: Question about Mass%
Replies: 14
Views: 145

Re: Question about Mass%

Since the mass percentage compositions of the elements where calculated, you know how much of each element is in the compound as percentages. Using 100g instead of the actual 8.00g value makes it easier so you don't have to figure out the actual amounts of each element. The answer is not affected by...

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