Search found 50 matches

by Heidi Buri 2I
Sat Dec 12, 2020 8:50 pm
Forum: Lewis Structures
Topic: Valence Electrons
Replies: 5
Views: 330

Re: Valence Electrons

Hi! To determine how many valence electrons and element has, it is helpful to look at the period table, specifically the column number. For groups 1-2 and 13-18, there are specific numbers of valence electrons. Group 1 has one valence electron and group 2 has two valence electrons. Group 13 has 3 va...
by Heidi Buri 2I
Sat Dec 12, 2020 8:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs Angular
Replies: 20
Views: 89

Re: Bent vs Angular

Hi! I believe that bent and angular are technical the same thing. They are just different names for the same shapes. There are two shapes that can be denoted as bent (or angular). These shapes involve a shape with one central atom, two bonding atoms, and one lone pair (VSPER formula of AX2E) and a s...
by Heidi Buri 2I
Sat Dec 12, 2020 8:32 pm
Forum: Lewis Acids & Bases
Topic: Identifying Lewis Acids and Bases
Replies: 3
Views: 44

Re: Identifying Lewis Acids and Bases

Hi! Lewis bases are molecules that can donate a pair of non-bonding electrons. Lewis acids are molecules that can accept pair of non-bonding electrons. An example of a lewis acid is H+. An example of a Lewis base is OH-. It is helpful to look a the charge of the molecules in the reaction to determin...
by Heidi Buri 2I
Sat Dec 12, 2020 8:20 pm
Forum: DeBroglie Equation
Topic: p
Replies: 19
Views: 155

Re: p

Hi! P stands for the momentum of the particle. The momentum of the particle can be calculated by the mass multiplied by the mass of the particle multiplied by the velocity (speed of the particle). On the equation sheet, the De Broglie equation is given as λ = h/p. The p equation is also given on the...
by Heidi Buri 2I
Sat Dec 12, 2020 8:15 pm
Forum: Identifying Acidic & Basic Salts
Topic: Acidic, basic, or neutral?
Replies: 8
Views: 67

Re: Acidic, basic, or neutral?

Hi! To observe if a salt is acidic, basic, or neutral, it helps to observe what happens after the salt is dissolved in a solution. After the salt is dissolved in a solution, if an acidic solution is produced, the salt has acidic character. After the salt is dissolved in a solution, if a basic soluti...
by Heidi Buri 2I
Sat Dec 12, 2020 8:10 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Strength of bases
Replies: 2
Views: 115

Re: Strength of bases

Hi! To determine if a base is strong, you can see the amount of of electricity it conducts. If a base conducts a great amount of energy, it is strong. Also, a song base is a substance that will completely dissociate and produce hydroxide (OH-).
by Heidi Buri 2I
Sat Dec 12, 2020 12:11 pm
Forum: Sigma & Pi Bonds
Topic: Pi bonds
Replies: 7
Views: 48

Re: Pi bonds

Hi! Yes, pi bonds to appear when there is a double or triple bond. In a double bond, there is one pi bond. In a triple bond, there are two pi bonds. I don't believe we need to know which is which, just when pi bonds exist, where the pi bonds would be in the molecule, and how many pi bonds there are.
by Heidi Buri 2I
Sat Dec 12, 2020 12:07 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 26
Views: 183

Re: Wavelength

Hi! When doing the calculations, wavelength will be in m. This is because the values of all the constants are in terms of meters. After finding the value of the wavelength in meters, it can be converted to nm. I would assume that the wavelength is in meters, but if the problem asks for the wavelengt...
by Heidi Buri 2I
Sat Dec 12, 2020 12:03 pm
Forum: Empirical & Molecular Formulas
Topic: Dealing with Diatomic Elements
Replies: 11
Views: 116

Re: Dealing with Diatomic Elements

Hi! To find the moles of Nigrogen, I would treat it as N. I believe you would have to use the amount of N2 to find N. This can be converted using stoichiometry. Once using stoichiometry to find the value of N, you would be able to use this value in the molecular formula.
by Heidi Buri 2I
Sat Dec 12, 2020 11:57 am
Forum: SI Units, Unit Conversions
Topic: SI Unit for Mass
Replies: 10
Views: 101

Re: SI Unit for Mass

Hi! The standard unit of mass (SI unit) is kilograms. I would recommend converting to grams for most equations until it is specifically asking for grams. When converting from kilograms to grams just use that 1 kilogram = 1000 grams.
by Heidi Buri 2I
Sat Dec 12, 2020 11:44 am
Forum: Amphoteric Compounds
Topic: How to know if a molecule is amphoteric
Replies: 9
Views: 97

Re: How to know if a molecule is amphoteric

Hi! An amphoteric molecule that can either donate a proton (and act as an acid) or accept a proton (and act as a base).HSO4- is an amphoteric molecule. This is because it can either donate a proton (acting as an acid) and become SO42- or accept a proton (acting as a base) and become H2S02. HC03- is ...
by Heidi Buri 2I
Thu Dec 03, 2020 2:33 pm
Forum: Naming
Topic: Oxidation State
Replies: 16
Views: 72

Re: Oxidation State

Hi! An oxidation state can also be known as an oxidation number. This oxidation number represents the number of electrons an atom either gains or loses in a reaction. For example, for a Cu2+ atom, the charge is 2+, so the oxidation number would also be +2.
by Heidi Buri 2I
Thu Dec 03, 2020 2:17 pm
Forum: Amphoteric Compounds
Topic: Amphoteric vs Amphiprotic
Replies: 13
Views: 468

Re: Amphoteric vs Amphiprotic

Hi! There are both similarities between amphoteric and amphoprotic molecules. An amphoteric molecule is a molecule that can act as both an acid or a base (ex: H2O). An amphiprotic molecule is a molecule that can both accept a proton or donate a proton. All amphoteric molecules can be considered amph...
by Heidi Buri 2I
Thu Dec 03, 2020 2:02 pm
Forum: Lewis Acids & Bases
Topic: Water
Replies: 62
Views: 480

Re: Water

Hi! Water can be considered an acid or base, depending on the reaction. If a water molecule accepts a proton in a reaction, it is considered a base. If a water molecule donates a proton, it is considered an acid. A water molecule can be considered an acid or a base based on how protons are transferr...
by Heidi Buri 2I
Mon Nov 30, 2020 1:45 pm
Forum: Bronsted Acids & Bases
Topic: Hydrogen Bonding
Replies: 16
Views: 303

Re: Hydrogen Bonding

Hi! The formation of a hydrogen bond can be considered an interaction between a Lewis acid and base. In a hydrogen bond, there is always a donor (H) and acceptor (what is binding to the H atom. For this reason, a formation of a hydrogen bond can be considered an interaction between a Lewis acid and ...
by Heidi Buri 2I
Mon Nov 30, 2020 1:41 pm
Forum: Lewis Acids & Bases
Topic: Determining Lewis Acids and Bases
Replies: 9
Views: 47

Re: Determining Lewis Acids and Bases

Hi! Lewis acids accept pairs of electrons while lewis bases donate pairs of electrons. In order to know if a substance is an acceptor or not, you have to look at how the act in a relation. In reactions, acceptors act as oxidizing agents (gains electrons in a relation).
by Heidi Buri 2I
Mon Nov 30, 2020 1:34 pm
Forum: Biological Examples
Topic: Hemoglobin vs. Myoglobin
Replies: 29
Views: 215

Re: Hemoglobin vs. Myoglobin

Hi! Both hemoglobin and myoglobin are protons that carry oxygen. Hemoglobin and myoglobin both carries and transports oxygen. Different than hemoglobin, myoglobin has a higher affinity for oxygen atoms, meaning that it is less likely to release oxygen than hemoglobin. Due to its higher affinity for ...
by Heidi Buri 2I
Mon Nov 30, 2020 1:27 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 30
Views: 152

Re: Polarity

Hi! A molecule can be made up of polar bonds but not be a polar molecule due to the arrangement of the atoms. A molecule can have a symmetrical arrangement of polar bonds. This symmetrical arrangement of polar bonds can make a molecule that has polar bonds but is not polar as a whole molecule.
by Heidi Buri 2I
Mon Nov 30, 2020 1:20 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids & Bases
Replies: 12
Views: 88

Re: Lewis Acids & Bases

Hi! For Lewis acids and bases, lewis acids accept pairs of electrons and Lewis bases donate pairs of electrons. An example of a lewis acid is H+ as it can accept a pair of electrons. An example of a Lewis base is OH- as it can donate a pair of electrons. This relates to traditional acids and bases a...
by Heidi Buri 2I
Mon Nov 30, 2020 1:14 pm
Forum: Electronegativity
Topic: Periodic Table Trend
Replies: 37
Views: 387

Re: Periodic Table Trend

Hi! On the periodic table, electronegativity increases from left to right and decreases from top to bottom. For ionization energy, it generally decreases from top to bottom and increases from left to right.
by Heidi Buri 2I
Fri Nov 27, 2020 8:22 pm
Forum: Electronegativity
Topic: General Explanation
Replies: 9
Views: 95

Re: General Explanation

Hi! Usually, an atom that has a higher electronegativity is more reactive. This means that in a reaction, an atom with a higher electronegativity is more likely to take electrons from other atoms to complete its octet.
by Heidi Buri 2I
Fri Nov 27, 2020 8:18 pm
Forum: Ionic & Covalent Bonds
Topic: Molecule size and ionic character
Replies: 13
Views: 113

Re: Molecule size and ionic character

Hi! Yes, the size of a molecule does affect the ionic character. In general, as the size of the molecule increases, the amount of ionic character decreases.
by Heidi Buri 2I
Fri Nov 27, 2020 8:14 pm
Forum: Dipole Moments
Topic: Boiling/Melting Points
Replies: 15
Views: 106

Re: Boiling/Melting Points

Hi! There are many reasons that molecules can have higher melting points. It has to do with qualities of the molecules. Usually, if molecules have higher dispersion forces or hydrogen bonding, the molecules have higher melting points. Also, ionic compounds have higher melting points due to the elect...
by Heidi Buri 2I
Fri Nov 27, 2020 8:10 pm
Forum: Ionic & Covalent Bonds
Topic: C-H bond polarity
Replies: 10
Views: 84

Re: C-H bond polarity

Hi! The C-H bond is considered non-polar due to the difference in electronegativy if the atoms. Carbon and Hydrogen have similar electronegativities. Due to this similarity in electronegativity values, the C-H bond is considered non-polar.
by Heidi Buri 2I
Fri Nov 27, 2020 8:06 pm
Forum: Lewis Structures
Topic: Identifying Lewis Acids and Bases
Replies: 8
Views: 57

Re: Identifying Lewis Acids and Bases

Hi! In general, Lewis acids are atoms that accept electrons, and a Lewis base is an atom that donates an electrons. Usually, when forming a molecule, the Lewis base has a negative charge and the Lewis acid has a negative charge
by Heidi Buri 2I
Fri Nov 27, 2020 8:00 pm
Forum: Lewis Structures
Topic: Dot stucture
Replies: 11
Views: 66

Re: Dot stucture

Hi! There are several steps to draw a lewis dot structure. The first step is to find the total number of valence electrons. Then, you need to figure out what atom is the central atom (which atom is the least electronegative or has the most valence electrons). Then, you can put the electrons around t...
by Heidi Buri 2I
Fri Nov 27, 2020 7:52 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 14
Views: 91

Re: Covalent Character

Hi! Covalent character is how likely an atom is to share electrons with other atoms. There are trends of covalent character on the periodic table. As you move down a groups on the periodic table, the covalent character increases, and the covalent character decreases as you move left to right in peri...
by Heidi Buri 2I
Fri Nov 27, 2020 7:45 pm
Forum: Trends in The Periodic Table
Topic: Ionic radius trends
Replies: 7
Views: 103

Re: Ionic radius trends

Hi! As the charge become more positive, the ionic radius usually decreases. This is because there are fewer electrons in the atom. As there are fewer electrons, the electrons are pulled closer to the nucleus of the atom. When an ion is more negative, the ionic radius increases because the electrons ...
by Heidi Buri 2I
Fri Nov 27, 2020 7:37 pm
Forum: Bond Lengths & Energies
Topic: Ionic Character
Replies: 12
Views: 3333

Re: Ionic Character

Hi! In order to determine the ionic character of a molecule, you need to look at the electronegativity of atoms in the molecule. If there is a greater difference in electronegativity between atoms, the molecule has more ionic character. NaBr would have a greater ionic character than NaI. This is bec...
by Heidi Buri 2I
Fri Nov 27, 2020 7:31 pm
Forum: Electronegativity
Topic: polar vs nonpolar
Replies: 19
Views: 71

Re: polar vs nonpolar

Hi! I believe that the minimum numerical difference in electronegativity in order for a molecule to be considered polar is 1.6 less. Also, if the difference in electronegativity is less than .05, the molecule is usually considered non polar.
by Heidi Buri 2I
Mon Nov 16, 2020 4:11 pm
Forum: Electronegativity
Topic: hydrogen bonds w/ carbon
Replies: 5
Views: 34

Re: hydrogen bonds w/ carbon

Hi! I believe the reason hydrogen can't make a hydrogen bond with carbon is due to electronegative and bond length. Carbon and hydrogen have a very small difference in electronegativities which makes the bond non-polar. H makes hydrogen bonds with N, O, and F due to their high difference in electron...
by Heidi Buri 2I
Mon Nov 16, 2020 4:05 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 11
Views: 89

Re: Resonance

Hi! To determine which resonance structure is the most stable/favorable, you must look at the covalent bonds in the structure, the formal charge, and the separation of formal charge. Resonance stuctures with more covalent bonds, the least number of formal charges, and with the least separation of fo...
by Heidi Buri 2I
Mon Nov 16, 2020 4:00 pm
Forum: Dipole Moments
Topic: london dispersion forces
Replies: 5
Views: 44

Re: london dispersion forces

Hi! All molecules experience London dispersion forces. Some molecules have larger or smaller London dispersion forces depending on the size. To determine if the molecules have more than just London dispersion focus, you must look at the other properties of the molecules and the atoms bonded to make ...
by Heidi Buri 2I
Mon Nov 09, 2020 12:09 am
Forum: Trends in The Periodic Table
Topic: positive and negative ion
Replies: 14
Views: 72

Re: positive and negative ion

Hi! I believe that the radius of an element is smaller when the ion is positive. When the ion is negative, the radius of the element is larger.
by Heidi Buri 2I
Mon Nov 09, 2020 12:05 am
Forum: Resonance Structures
Topic: Valence Electrons [ENDORSED]
Replies: 43
Views: 247

Re: Valence Electrons [ENDORSED]

Hi! Yes the placement of elements on the periodic table can provide insight on the number of valence electrons. Specifically, elements within the 1-2 and 13-18 columns, the number of valence electrons increased (1 valence electron for hydrogen and 8 valence electrons for He).
by Heidi Buri 2I
Sun Nov 01, 2020 2:27 pm
Forum: Quantum Numbers and The H-Atom
Topic: explanation of ml
Replies: 4
Views: 29

Re: explanation of ml

Hi! I believe that ml provides information on the orientation of an orbital. This orientation is depended on n and l (n being the energy level and l being she shape). For orbital shapes, there are different orientations. The ml value will give the orientation of a specific shape in an energy level.
by Heidi Buri 2I
Sun Nov 01, 2020 2:23 pm
Forum: Trends in The Periodic Table
Topic: Periodic Table & Electron Affinity
Replies: 11
Views: 70

Re: Periodic Table & Electron Affinity

Electron affinity depends on the number of valence electrons that an atom has. When there are more valence electrons, the more likely the atom will gain electrons. The number of valance electrons ca be observed on the periodic table. I believe that on a periodic table, the electron affinity decrease...
by Heidi Buri 2I
Sun Nov 01, 2020 2:19 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 9
Views: 76

Re: Covalent Bonds

Covalent bonds are the strongest out of the three. This is because of the stability of the bond due to electrons being shared between atoms. Ionic bonds form differently than covalent bonds. Ionic bonds usually form between atoms that differ greatly in electronegativity. Both ionic and covalent bond...
by Heidi Buri 2I
Sun Nov 01, 2020 2:14 pm
Forum: Ionic & Covalent Bonds
Topic: hydrogen
Replies: 19
Views: 230

Re: hydrogen

Hydrogen bonding can occur when a hydrogen binds to either fluorine, oxygen or nitrogen. This only occurs with these three elements due to their electronegative properties. Fluorine, Oxygen, and Nitrogen are all very electronegative, so when they bing to hydrogen bonds there are partial negative and...
by Heidi Buri 2I
Sun Nov 01, 2020 2:11 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of bonds
Replies: 13
Views: 90

Re: Strength of bonds

Hi! I believe it goes covalent bonds, ionic bonds, hydrogen bonds, and then van der Waals. Covalent bonds are the strongest as they require a high amount of energy to break.
by Heidi Buri 2I
Sun Oct 18, 2020 10:09 pm
Forum: Significant Figures
Topic: How do I know how many sig figs to use?
Replies: 6
Views: 94

Re: How do I know how many sig figs to use?

Hi! There are different rules for addition/subtraction or multiplication/division. When values are being added/subtracted, the final answer should have as many decimal places as the given value with the least amount of decimal places. For multiplication/division, the answer should have the same amou...
by Heidi Buri 2I
Sun Oct 18, 2020 9:54 pm
Forum: Properties of Electrons
Topic: Electron Configuration
Replies: 3
Views: 37

Re: Electron Configuration

Hi! I think that he order of the s and p electron subsheslls in the final electron configuration does matter. This is due to the way that the election shells are filled.
by Heidi Buri 2I
Sun Oct 18, 2020 9:40 pm
Forum: Properties of Electrons
Topic: protons and electrons
Replies: 33
Views: 191

Re: protons and electrons

Hi! Protons and electrons do not have the same mass. Protons are thought to have a mass of 1 atomic mass unit (amu)while electrons are thought to have a mass that is very close to 0 amu. Similar to protons, neutrons are thought to have the mass of 1 amu. The masses of protons and neutrons are approx...
by Heidi Buri 2I
Sun Oct 18, 2020 9:35 pm
Forum: Einstein Equation
Topic: What are the units for E
Replies: 16
Views: 124

Re: What are the units for E

Hi! In the equation E=hv, I believe that the units for E are in Joules. The reasoning behind this is because E is the energy of a photon. Since energy is measured in Joules, E would be in Joules.
by Heidi Buri 2I
Sun Oct 18, 2020 9:32 pm
Forum: Properties of Light
Topic: Photons
Replies: 9
Views: 81

Re: Photons

Hi! I was also confused on the concept of a photon. I believe that it is a particle that is made up of energy. A photon is the particle that makes up light. A photon is thought to not have mass.
by Heidi Buri 2I
Fri Oct 09, 2020 11:36 pm
Forum: Significant Figures
Topic: How to deal with significant figures in decimals with zeros.
Replies: 20
Views: 194

Re: How to deal with significant figures in decimals with zeros.

According to the significant figures rules, all trailing zeros after a decimal point are considered significant. Additionally, all zeros that are located in-between other non-zero figures are considered significant. In the example you provided, I believe that there would be 4 significant figures. Th...
by Heidi Buri 2I
Fri Oct 09, 2020 11:17 pm
Forum: SI Units, Unit Conversions
Topic: Kg to g
Replies: 13
Views: 136

Re: Kg to g

I believe that in order to convert kg to g you must multiply the amount of kilograms you have by 1000. For example, if there was 6 kg, and you wanted to know how many grams there are, you would multiply the 6 by 1000, and you would discover that 6kg is the same is 6000 g. If you had the amount of gr...
by Heidi Buri 2I
Fri Oct 09, 2020 1:45 pm
Forum: Molarity, Solutions, Dilutions
Topic: NaHCO3
Replies: 2
Views: 48

Re: NaHCO3

For part a, I also calculated the mass of NaHCO3 needed to prepare the solution to be 12.286 grams. I calculated this by first using the M=mol/L formula. After finding the moles needed I then converted moles to grams. For part b, I beehive that the total volume would end up being 100ml as only a 100...
by Heidi Buri 2I
Fri Oct 09, 2020 1:25 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Molar Mass and Molecular Mass Difference?
Replies: 21
Views: 255

Re: Molar Mass and Molecular Mass Difference?

Usually, the molecular mass is thought of as the mass of particular molecules. There can be various molecular masses based on the different masses of isotopes. For example, the isotopes of carbon (carbon-12, carbon-13, and carbon-14) would all have different molecular masses due to their different i...
by Heidi Buri 2I
Fri Oct 09, 2020 1:11 pm
Forum: Significant Figures
Topic: How many significant figures are in 7.00 x 10^2?
Replies: 25
Views: 566

Re: How many significant figures are in 7.00 x 10^2?

I think there would be three significant figures as all non-zero digits are considered significant figures and all trailing zeros after a decimal point are also considered significant figures. In this case, 7 would be a significant figure as it is a non-zero value, and the two zeros after the decima...

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