Search found 68 matches

by William Chan 1D
Thu Jan 30, 2020 3:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic reaction
Replies: 18
Views: 43

Re: Exothermic reaction

If a reaction is exothermic, you can treat heat as a "reactant," where increasing the overall temperature will shift the equilibrium to the left, and decreasing the overall temperature will shift the reaction to the right.
by William Chan 1D
Thu Jan 30, 2020 3:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Negative pH
Replies: 9
Views: 35

Re: Negative pH

pH is simply -log([H3O+]). When the molarity of H3O+ is higher than 1 M, then the pH will begin to become negative. Acids aren't typically this strong, and there's actually a special category for such strong acids called superacids, but they aren't common.
by William Chan 1D
Thu Jan 30, 2020 3:02 pm
Forum: Ideal Gases
Topic: Inert Gas
Replies: 12
Views: 30

Re: Inert Gas

Inert gases are gases that don't react with any of the reactants or products. Noble gases are often used because they are notoriously unreactive.
by William Chan 1D
Thu Jan 30, 2020 2:58 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter q
Replies: 2
Views: 13

Re: Calorimeter q

When using a bomb calorimeter, we are usually measuring a change in the surroundings, and since q(system) = -q(surroundings), it'll be the opposite sign you measure in the surroundings. For example, for an exothermic reaction, you measure an increase in q of the surroundings, so q be positive for th...
by William Chan 1D
Fri Jan 24, 2020 10:29 am
Forum: Phase Changes & Related Calculations
Topic: Autoprotolysis
Replies: 15
Views: 80

Re: Autoprotolysis

It is proton transfer between two of the same molecule. For example, if we have two water molecules, one can donate a proton to the other, and result in OH- and H30+ molecules.
by William Chan 1D
Sun Jan 19, 2020 12:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Titration
Replies: 1
Views: 13

Re: Titration

That's a vague question, but a titration is a procedure to determine the concentration of an unknown acid or base using titrant of a known concentration. The titrant is added until the equivalence point is reached. Using the information on how much titrant was used, we can solve for the concentratio...
by William Chan 1D
Sun Jan 19, 2020 12:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Solids and Liquids
Replies: 6
Views: 23

Re: Solids and Liquids

Solids and liquids are essentially non-compressible, so their concentrations don't really change. Gas concentrations or ion concentrations will change though, those are the values we calculate for.
by William Chan 1D
Sun Jan 19, 2020 12:18 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic vs. exothermic
Replies: 5
Views: 14

Re: Endothermic vs. exothermic

If a reaction is endothermic, it means it absorbs heat when the reaction proceeds forward. Adding more heat allows more forward reactions to occur, shifting the equilibrium to the right. It something helps to think of heat as a reactant in this case, where, according to Le Chatlier's principle, addi...
by William Chan 1D
Sun Jan 12, 2020 6:28 pm
Forum: Ideal Gases
Topic: Ideal Gas Law
Replies: 3
Views: 22

Ideal Gas Law

Under what conditions does the ideal gas law deviate and why? Do we need to memorize why?
by William Chan 1D
Sun Jan 12, 2020 6:27 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: the "quick way"
Replies: 4
Views: 18

Re: the "quick way"

The "quick" way refers to looking at the moles of gas on each side of the equation, and when pressure changes, let's say increased, then the reaction will shift toward the side with fewer moles of gas because it "relieves" some of the pressure.
by William Chan 1D
Sun Jan 12, 2020 6:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: memorization
Replies: 12
Views: 38

Re: memorization

I don't think we'll be expected to memorize k values, and will most likely be given by the problem.
by William Chan 1D
Sun Jan 12, 2020 6:22 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Situations in which Q=K
Replies: 7
Views: 27

Re: Situations in which Q=K

If Q = K, then the reaction is at equilibrium.
by William Chan 1D
Sun Jan 12, 2020 6:22 pm
Forum: Ideal Gases
Topic: Bars vs atmospheres
Replies: 13
Views: 36

Re: Bars vs atmospheres

They are both units of pressure and can be interchanged through unit conversions (like pounds and kilograms).
by William Chan 1D
Sun Jan 12, 2020 6:19 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: appliction of principle
Replies: 5
Views: 16

Re: appliction of principle

It applies to changes in temperature, pressure (only when it changes the concentration from a change in volume), or a direct change in concentration (from adding reactants/products).
by William Chan 1D
Sun Jan 12, 2020 5:55 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 6
Views: 25

Re: Q and K

K is a constant which doesn't change. Q is the reaction quotient, which is calculated the same as K, but the key difference is that k is calculated when the reaction is at equilibrium, while q doesn't have to be. q can be used to determine whether or not the equation will proceed forward or backward.
by William Chan 1D
Sun Jan 12, 2020 5:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 21
Views: 57

Re: Units for K

K doesn't have units technically because they all cancel out, and it comes out to be just a number ratio.
by William Chan 1D
Sun Jan 12, 2020 5:50 pm
Forum: Ideal Gases
Topic: ICE tables
Replies: 4
Views: 16

Re: ICE tables

Ice tables are just to help us keep track of the molar concentrations before and after reactions occur. I stands for Initial concentration C stands for Change in concentration E stands for Equilibrium concentration We denote the change in concentration in terms 'x' usually, and solve for it to deter...
by William Chan 1D
Fri Jan 10, 2020 11:04 am
Forum: Ideal Gases
Topic: Difference between K and Q
Replies: 9
Views: 30

Re: Difference between K and Q

K, the equilibrium constant, is a constant, which at some set conditions, is a constant at equilibrium. Q is calculated the same way but is calculated to see whether the reaction proceeds forward or backward to reach equilibrium.
by William Chan 1D
Fri Dec 06, 2019 11:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polarity from VSPER
Replies: 4
Views: 33

Re: Determining polarity from VSPER

You can use VSEPR to determine the shape, some of which can more easily lead to polarization than others. In general, though, you need to know the electronegativity of the atoms.
by William Chan 1D
Sun Dec 01, 2019 11:01 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids - Example from Lecture
Replies: 6
Views: 35

Re: Strength of Acids - Example from Lecture

Trichloroacetic acid has 3 chlorine molecules, which pull harder on the electrons because chlorine has a higher electronegativity than hydrogen does. The stability of the anion determines the strength of the acid. When either trichloroacetic acid or acetic acid loses a hydrogen ion, the oxygen is le...
by William Chan 1D
Sun Dec 01, 2019 10:56 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Reactions, Equilibrium
Replies: 4
Views: 23

Re: Reactions, Equilibrium

Remember that many chemical equations are at equilibrium, where there are forward and backward reactions happening all the tine. If a reaction is "favored to the right," the reactants will react/decay to form more products. If the reaction is "favored to the left," then the produ...
by William Chan 1D
Sun Dec 01, 2019 10:52 am
Forum: Air Pollution & Acid Rain
Topic: Clean Coal vs Dirty Coal?
Replies: 16
Views: 123

Re: Clean Coal vs Dirty Coal?

I think it's based on the sulfur content. The higher the sulfur content of the coal, the "dirtier" it is because, when burned, it'll react with the air to create acid rain.
by William Chan 1D
Sun Dec 01, 2019 10:51 am
Forum: Polyprotic Acids & Bases
Topic: How can you tell
Replies: 11
Views: 99

Re: How can you tell

If there's more than one H in front of the anion, let's say,

H2SO4, or H3PO4

It'll be polyprotic because there is more than 1 hydrogen in front.
by William Chan 1D
Sat Nov 30, 2019 5:55 pm
Forum: Lewis Acids & Bases
Topic: Identifying lewis acids and bases
Replies: 4
Views: 20

Identifying lewis acids and bases

How can we identify lewis acids and bases?
by William Chan 1D
Sat Nov 30, 2019 5:54 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong acid/weak base interaction
Replies: 1
Views: 17

Strong acid/weak base interaction

Will we have to figure out the pH of a weak acid/strong base interaction at equilibrium?
by William Chan 1D
Sat Nov 30, 2019 5:53 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH vs. pOH
Replies: 17
Views: 127

Re: pH vs. pOH

In most circumstances, we measure pH of a solution. It makes things easier/more standard, but we can also measure pOH. Just as pH is defined by -log[H+], pOH is defined by -log[OH-]. Because of the equilibrium constant of water, pH and pOH have an inverse relationship. pH = 14 - pOH, and pOH = 14 - ...
by William Chan 1D
Sat Nov 30, 2019 5:48 pm
Forum: Polyprotic Acids & Bases
Topic: polyprotic v. bronsted
Replies: 3
Views: 44

Re: polyprotic v. bronsted

A Bronsted acid is simply defined as a proton donor.

A polyprotic acid is an acid can give multiple H+ ions to a solution, so yes, it is considered a Bronsted acid.
by William Chan 1D
Sat Nov 30, 2019 5:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH out of the 0-14 scale
Replies: 2
Views: 19

Re: pH out of the 0-14 scale

pH is a measure of the concentration of H+ ions, or more accurately, H3O+.

It's measured using the -log[H+].

The normal pH range is 1 - 14, but if the H+ concentration is higher (super acid) or lower (super base), it'll be outside that range.
by William Chan 1D
Sat Nov 30, 2019 3:33 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 3
Views: 37

Cisplatin

Should we memorize the structure of cisplatin and transplatin? And what about hemoglobin and myoglobin?
by William Chan 1D
Sun Nov 24, 2019 1:06 am
Forum: Biological Examples
Topic: Biological Importance
Replies: 6
Views: 25

Re: Biological Importance

In class, we did discuss cisplatin and hemoglobin/myoglobin, but I think he was discussing these more to show the prevalence of coordination compounds in biological systems. It certainly wouldn't hurt to understand a little bit about how these molecules function, but I don't think we need to know th...
by William Chan 1D
Sun Nov 24, 2019 12:47 am
Forum: Naming
Topic: Prefixes
Replies: 4
Views: 33

Re: Prefixes

What are some examples of when we would need to use this naming convention?
by William Chan 1D
Sun Nov 24, 2019 12:46 am
Forum: Naming
Topic: Coordination sphere
Replies: 1
Views: 20

Re: Coordination sphere

Ligands that are attached to the central ion (transition metal) would be considered inside the coordination sphere.
by William Chan 1D
Sun Nov 24, 2019 12:44 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand
Replies: 3
Views: 16

Re: Ligand

They can be thought of as the electron pair donors. They attach to the transition metal to form the coordination compouds.
by William Chan 1D
Sun Nov 24, 2019 12:41 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cation outside coordination sphere
Replies: 2
Views: 22

Re: Cation outside coordination sphere

The coordination sphere is made up of the ligands directly attached to the central ion.
If the coordination sphere has a net negative charge, it has the potential to attract cations to help neutralize the charge.
by William Chan 1D
Mon Nov 18, 2019 4:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Stronger IMF's
Replies: 2
Views: 26

Re: Stronger IMF's

I can't say for certain but I believe that the number of electrons is more important than the shape. Whether it's linear or not will affect the IMF's, but I believe that, if anything, we will only have to compare molecules with the same molecular formula but different shapes, not something like this.
by William Chan 1D
Mon Nov 18, 2019 4:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 2
Views: 22

Re: Bond Angles

Yes, know bond angles for shapes.
Some key numbers are: 180°, 120°, 109.5°, and 90°
Lone electron pairs will push bonds closer together, making them slightly less than what those angles would be.
by William Chan 1D
Mon Nov 18, 2019 4:23 pm
Forum: Hybridization
Topic: Test 2
Replies: 11
Views: 74

Re: Test 2

Lavelle mentioned that hybridization wouldn't be on Test 2.
by William Chan 1D
Fri Nov 15, 2019 12:51 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 5
Views: 26

Re: Octahedral

All of the mentioned shapes have 6 pairs of electrons around the central atom. What differs is how many lone pairs and bonding pairs each has. Octahedral structures have 6 bonding pairs and 0 lone pairs. Square pyramidal structures have 5 bonding pairs and 1 lone pair. This one, as the name suggests...
by William Chan 1D
Fri Nov 15, 2019 12:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 9
Views: 41

Re: bond angles

When an atom has lone pairs of electrons, the bond angles are often written with a "less-than" symbol because lone electron pairs have a slightly higher repulsion than normal bonding pairs do, so they push them away more lone pairs, and thus a little closer to other bonding pairs.
by William Chan 1D
Mon Nov 11, 2019 12:58 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: Dipole-Dipole vs Dipole-Induced
Replies: 2
Views: 16

Re: Dipole-Dipole vs Dipole-Induced

There are differences. Dipole-dipole interactions are present in polar molecules that have a side with a partial negative and a side with a partial positive charge. These partial charges create attractions between the molecules. Induced-dipole induced-dipole interactions are present in all molecules...
by William Chan 1D
Mon Nov 11, 2019 12:54 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: forces and boiling points
Replies: 6
Views: 19

Re: forces and boiling points

The boiling point of a molecule is determined by that molecule's IMF's, or intermolecular forces. The stronger the IMF's the higher the boiling point, and the lower the IMF's the lower the boiling point. CH4 and CCl4 are similar atoms, but the key difference is that chlorine has many more electrons ...
by William Chan 1D
Mon Nov 11, 2019 12:50 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: Hydrogen Bonding with Elements
Replies: 2
Views: 14

Re: Hydrogen Bonding with Elements

Nitrogen, oxygen, and fluorine have a relatively high electronegativity. When bonded with a hydrogen atom, these atoms will typically have a stronger partial negative charge, leaving hydrogen with a stronger partial positive charge. This makes the IMF's of these molecules stronger.
by William Chan 1D
Mon Nov 11, 2019 12:46 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: difference between intermolecular forces
Replies: 3
Views: 18

Re: difference between intermolecular forces

Dipole-dipole interactions are attractions between polar molecules with partial charges. Hydrogen bonding is similar to dipole-dipole interactions but is considered stronger because of the presence of hydrogen, and another strongly electronegative atom (N, O, or F) For practical purposes, Lavelle sa...
by William Chan 1D
Mon Nov 11, 2019 12:40 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 Forces??
Replies: 3
Views: 18

Re: London Forces??

All molecules have London forces. These forces happen as a result of the random, uneven electron distribution around molecules. The more electrons an atom has, the stronger these forces will be.
by William Chan 1D
Mon Nov 04, 2019 10:04 am
Forum: Resonance Structures
Topic: Octet
Replies: 13
Views: 84

Re: Octet

Filling the octet refers to the idea that most elements want to complete their valence shell.

The valence shell (for 2nd period, usually for elements after carbon) will be the s and p subshells, which will have 8 electrons total.
by William Chan 1D
Mon Nov 04, 2019 10:01 am
Forum: Lewis Structures
Topic: Lewis Dot Structures
Replies: 4
Views: 24

Re: Lewis Dot Structures

I think that it's better to put one dot on each side
by William Chan 1D
Mon Nov 04, 2019 9:59 am
Forum: Ionic & Covalent Bonds
Topic: Strength and Length
Replies: 18
Views: 111

Re: Strength and Length

Longer bonds generally mean they're weaker, and shorter bonds generally mean they're stronger.
by William Chan 1D
Fri Nov 01, 2019 1:14 pm
Forum: Bond Lengths & Energies
Topic: Lone electron pairs weakening bonds
Replies: 4
Views: 21

Lone electron pairs weakening bonds

Dr. Lavelle talked about how fluorine, F2, has a weaker than expected bond strength because of lone electron pairs on neighboring atoms.

Why do lone electron pairs on neighboring atoms weaken the bonds?
by William Chan 1D
Sat Oct 26, 2019 3:34 pm
Forum: Ionic & Covalent Bonds
Topic: Cation
Replies: 23
Views: 187

Re: Cation

Cations are atoms that have lost an electron and therefore have a positive charge. Anions are atoms that have gained an electron and therefore have a negative charge. Cations and anions are important to understand because they tell us why certain things like ionic salts can form, and also has applic...
by William Chan 1D
Sat Oct 26, 2019 3:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Notation
Replies: 5
Views: 32

Electron Configuration Notation

In high school, we would fill out the electron configuration with the order they would fill in... for example bromine: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 ... but in Lavelle's lecture, he said that we should fill them in with respect to their energy levels... bromine: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5 A...
by William Chan 1D
Fri Oct 25, 2019 10:35 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Sulfur bonding
Replies: 5
Views: 30

Sulfur bonding

In lecture today, Lavelle showed that sulfur can have 6 bonds (2 double bonds, 2 single bonds). Wouldn’t that be more than a full shell (of 8 e-)? Why is this allowed?
by William Chan 1D
Thu Oct 24, 2019 8:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Exceptions
Replies: 3
Views: 24

Electron Configuration Exceptions

What kind of electron configuration exceptions are we expected to know? I know that Chromium and Copper will take an electron from the s subshell to stabilize the d subshell, but is there anything else we need to know?
by William Chan 1D
Sun Oct 20, 2019 11:13 pm
Forum: Properties of Light
Topic: speed of light and velocity
Replies: 6
Views: 37

Re: speed of light and velocity

Velocity and speed are often used interchangeably. None of the calculations we make in this class will necessarily require us to know the direction of light, so we just focus on the speed instead.
by William Chan 1D
Sun Oct 20, 2019 11:11 pm
Forum: Properties of Light
Topic: Balmer and Lyman Series
Replies: 5
Views: 45

Re: Balmer and Lyman Series

I believe you mean when the hydrogen electron gets excited. The lowest energy level is n=1, and it goes up from there, n = 2, 3, etc. Let's say we have an electron at n =2. When a photon with the right amount of energy hits an electron, it will excite it to a higher energy level, let's say n = 3. It...
by William Chan 1D
Sun Oct 20, 2019 10:40 pm
Forum: Properties of Electrons
Topic: Mass of Proton, Electron and Neutron
Replies: 2
Views: 27

Re: Mass of Proton, Electron and Neutron

It will be on the reference sheet. You won't need to memorize them.
by William Chan 1D
Sat Oct 19, 2019 8:28 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Spin
Replies: 4
Views: 49

Magnetic Spin

Do we need to know magnetic spin for the test? Also, why is it + or - 1/2, and not a whole number?
by William Chan 1D
Sat Oct 19, 2019 8:23 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrostatic potential energy
Replies: 2
Views: 34

Re: Electrostatic potential energy

Electrostatic potential energy is essentially the force that charged particles, like protons and electrons, will "feel." Like charges will repel each other and opposite charges will attract. In multielectron systems, the net force on electrons in the outer shells is reduced due to shieldin...
by William Chan 1D
Thu Oct 17, 2019 9:11 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg constant
Replies: 3
Views: 28

Rydberg constant

Does the rydberg constant only work for hydrogen atoms? Or can you use it for every element to solve spectral line problems?
by William Chan 1D
Tue Oct 15, 2019 9:59 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: HW Question 1.D.13
Replies: 3
Views: 45

Re: HW Question 1.D.13

The question is asking for the angular quantum number, or l. In the question, they give us that n=7. n is the principal quantum number. The textbook goes more in depth about n, but for this question, they're asking for l. Given n, we can determine all the possible angular quantum numbers using the e...
by William Chan 1D
Tue Oct 15, 2019 12:48 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1B.25
Replies: 2
Views: 18

Re: 1B.25

h bar, or ℏ, is h/2π.
by William Chan 1D
Tue Oct 15, 2019 12:32 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW Question 1.B.27
Replies: 2
Views: 22

Re: HW Question 1.B.27

It's not h, it's h bar, or ℏ, which is equal to h/2π, or about 1.054457 x 10^34
by William Chan 1D
Tue Oct 15, 2019 12:30 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW Question 1.B.25
Replies: 3
Views: 36

Re: HW Question 1.B.25

The equation is ΔpΔx ≥ 1/2 ℏ.

Not that ℏ is equal to h/2π, so in essence, ΔpΔx is equal to h /π, or 1/2 ( h/2π ). I think this is where the other 1/2 came from.
by William Chan 1D
Tue Oct 15, 2019 12:24 am
Forum: Properties of Light
Topic: Angstrom
Replies: 10
Views: 65

Re: Angstrom

Usually leaving the answer in scientific notation (in powers of 10) is sufficient.
by William Chan 1D
Mon Sep 30, 2019 9:37 pm
Forum: Limiting Reactant Calculations
Topic: Methods of identifying Limiting Reactants
Replies: 5
Views: 87

Re: Methods of identifying Limiting Reactants

As far as I know, there isn't really any shortcut to determining the limiting reactant other than first converting the masses to moles, then comparing those numbers to the balanced chemical equation. I'm not really that efficient, I just trial and error, but this process shouldn't take too long.
by William Chan 1D
Mon Sep 30, 2019 9:31 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculations in Two-Step Reactions
Replies: 4
Views: 29

Re: Limiting Reactant Calculations in Two-Step Reactions

It appears that both chemical equations are balanced, which makes things a bit easier. The first step is to convert both masses to moles. Given 0.036g of methane, and that the molar mass of methane is about 16g/mol, we can determine that we have about 2.25 x 10^-3 mols of methane. Given 0.108 grams ...
by William Chan 1D
Mon Sep 30, 2019 4:55 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamental E Problem 1
Replies: 3
Views: 40

Re: Fundamental E Problem 1

Yes, in addition to knowing Avogadro's number, which is ~6.02 x 10^23, you would also need to take into account that the atom's radius is 144 pm, but its diameter would be 288 pm.
by William Chan 1D
Mon Sep 30, 2019 9:54 am
Forum: General Science Questions
Topic: Rusty on High School Chem [ENDORSED]
Replies: 169
Views: 103287

Re: Rusty on High School Chem [ENDORSED]

I took chemistry two years ago and I feel like the best way to stay on top of the material is actually do the HW and get feedback on it. Review lecture notes before assessments and as always, never be afraid to ask questions!
by William Chan 1D
Sun Sep 29, 2019 6:27 pm
Forum: Significant Figures
Topic: Calculations With Significant Figures
Replies: 3
Views: 80

Calculations With Significant Figures

When I do multiple calculations in my calculator, should I round every answer before I carry onto then next step using the appropriate number of sig figs, or should I just use the exact numbers the calculator gives me and at the end round using sig figs?

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