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Videos uploaded by user “Tyler DeWitt”
What are Isotopes?
 
07:56
To see all my Chemistry videos, check out http://socratic.org/chemistry We'll learn about what isotopes are and how to write atomic number and mass number in isotope notation. We talk about a simple analogy with cars to explain this tutorial. Isotopes are versions of an atom or an element that have the same number of protons, but different numbers of neutrons. Isotopes and isotope notation are particularly important in nuclear chemistry.
Views: 936231 Tyler DeWitt
Ionic Bonding Introduction
 
07:20
To see all my Chemistry videos, check out http://socratic.org/chemistry This video is an introduction to ionic bonding, which is one type of chemical bonding. Ionic bonds hold together metal and nonmetal atoms. In ionic bonding, electrons are transferred from a metal atom to a nonmetal atom, creating ions. These ions have opposite charge, so they stick together. Creative Commons Attribution-NonCommercial CC BY-NC
Views: 927724 Tyler DeWitt
What's an Ion?
 
06:52
To see all my Chemistry videos, check out http://socratic.org/chemistry Confused about ions? We'll learn the difference between an atom and an ion. Ions are formed because of a net charge on an atom, because the number of protons and electrons do not balance. This means that the atom is no longer electrically neutral, but is a cation or an anion. We also talk about polyatomic ions.
Views: 669495 Tyler DeWitt
Add and Subtract with Significant Figures (1.6)
 
04:43
To see all my Chemistry videos, check out http://socratic.org/chemistry How to do addition and subtraction with significant figures, also known as significant digits.
Views: 584704 Tyler DeWitt
What's a polyatomic ion?
 
05:15
To see all my Chemistry videos, check out http://socratic.org/chemistry We'll learn what polyatomic ions are. Polyatomic ions are created when a number of atoms come to together to form a group, and then that group has either a positive or a negative charge, which means that it can be either a cation or an anion. We discuss how protons and electrons balance to give a net charge, and then discuss some common polyatomic ions.
Views: 436702 Tyler DeWitt
What's the Difference Between Molarity and Molality?
 
05:11
To see all my Chemistry videos, check out http://socratic.org/chemistry What's the difference between molarity and molality? They are both measures of concentration, but molarity has to do with volume (in Liters) and molality has to do with mass (in kilograms). Also, molarity talks about the volume of the total solution (solute and solution combined), and molality is about mass of the solute and solvent separately.
Views: 186061 Tyler DeWitt
Ideal Gas Law Introduction
 
06:18
To see all my Chemistry videos, check out http://socratic.org/chemistry Discusses the ideal gas law PV=nRT, and how you use the different values for R: 0.0821, 8.31, and 62.4.
Views: 396544 Tyler DeWitt
Significant Figures and Zero (1.3)
 
07:37
To see all my Chemistry videos, check out http://socratic.org/chemistry When you're doing significant digits, how do you deal with zeros?
Views: 713515 Tyler DeWitt
What Happens when Stuff Dissolves?
 
04:10
To see all my Chemistry videos, check out http://socratic.org/chemistry We'll look at what happens when you dissolve ionic and covalent compounds in water. Ionic compounds break apart into the ions that make them up, a process called dissociation, while covalent compounds only break into the molecules, not the individual atoms.
Views: 364192 Tyler DeWitt
Multiplication and Division with Significant Zeros (1.5)
 
04:31
To see all my Chemistry videos, check out http://socratic.org/chemistry Now that we know when zeros are significant or not, we'll do multiplication and division and rounding with numbers that have zeros.
Views: 394371 Tyler DeWitt
Introduction to Oxidation Reduction (Redox) Reactions
 
13:05
This is an introduction to oxidation reduction reactions, which are often called redox reactions for short. An oxidation reduction (redox) reaction happens when electrons are transferred between atoms. A loss of electrons is called oxidation, and we say that atom has become oxidized. A gain of electrons is called reduction, and we say that the atoms has become reduced. The two separate parts (oxidation and reduction) of an oxidation reduction (redox) reaction are called half reactions. Two half reactions can be put together to make the whole reaction. Oxidation numbers are numbers that can be written above atoms to show whether they are gaining or losing electrons.
Views: 1391548 Tyler DeWitt
Ionic vs. Molecular
 
08:52
To see all my Chemistry videos, check out http://socratic.org/chemistry How can you tell the difference between compounds that are ionic and molecular (also known as covalent)? It has to do with the elements that make them up: ionic compounds are made of metals and nonmetals, and molecular (or covalent) compounds are made of nonmetals. We'll learn how they bond differently: in covalent compounds, the atoms share electrons, and in ion compounds, atoms steal electrons and then opposite charges attract. Ionic and molecular (covalent) compounds also look different at the microscopic level: covalent and molecular compounds exist in molecules, while ionic compounds are organized in lattice structures.
Views: 634527 Tyler DeWitt
Writing Ionic Formulas: Introduction
 
11:44
Here's how to write formulas for binary ionic compounds. We'll see how you have to balance the charges of the two ions so they cancel each other out.
Views: 1877763 Tyler DeWitt
Be Lazy! Don't Memorize the Gas Laws!
 
07:10
To see all my Chemistry videos, check out http://socratic.org/chemistry Here is a really fantastic shortcut you can use so you don't have to memorize any of these gas law: Boyle's Law, Charles' Law, Gay-Lussac's Law, Avogadro's Law, and the Combined Gas Law
Views: 498975 Tyler DeWitt
Balancing Chemical Equations Practice Problems
 
14:56
Equation balancing will make sense! Here, we will do a bunch of practice problems for balancing chemical equations. We'll see the process or trial and error and the steps that you have to go through to balance chemical equations. You start by keeping track of the number of atoms on both sides of the equation, and then you add coefficients to one or more of the elements and compounds to make the number of atoms equal.
Views: 1554013 Tyler DeWitt
Boyle's Law
 
05:42
To see all my Chemistry videos, check out http://socratic.org/chemistry An introduction to the relationship between pressure and volume, and an explanation of how to solve gas problems with Boyle's Law
Views: 450187 Tyler DeWitt
How to Calculate Oxidation Numbers Introduction
 
13:26
We'll learn how to determine the oxidation numbers or oxidation states for a the elements in a chemical compound. The oxidation numbers tell us how electrons are divided up or shared between atoms in a chemical compound. The oxidation numbers also tell us how electrons move in an oxidation reduction (redox) reaction. There are a set a rules that we use to determine oxidation number. Group 1A elements (alkalai metals) always have an oxidation of +1. Group 2A elements (alkaline earth metals) always have an oxidation number of +2. Elements on their own have an oxidation number of 0, and monatomic ions have an oxidation number that is equal to the ionic charge.
Views: 1006881 Tyler DeWitt
Naming Ionic Compounds with Transition Metals Introduction
 
10:10
We'll learn how to name ionic compounds that have transition metals in them. The names for transition metal compounds often have roman numerals in them, because the roman numerals indicate the charge on the transition metal. This is because transitional metal elements are able to make a variety of ions with different charge. In order to write the roman numeral for a transition metal compound, we need to work backwards, using the periodic table or a list of polyatomic ions to figure out what charge it has in that particular ionic compound.
Views: 869675 Tyler DeWitt
Introduction to Moles
 
10:50
A mole is like a dozen. It is a name for a specific number of things. There are 12 things in a dozen, and 602 hexillion things in a mole. We'll talk about what moles are and why they are important. We will see how to abbreviate the mole number (Avogadro's number) using scientific notation, and we'll see how giant this number is.
Views: 657419 Tyler DeWitt
Phase Changes: Exothermic or Endothermic?
 
06:44
To see all my Chemistry videos, check out http://socratic.org/chemistry We will learn which phase changes and exothermic, and which are endothermic. It all has to do with the direction of heat movement, or heat transfer. If heat transfers from the surroundings into a system, it is an endothermic process. If it transfers from a system into the surroundings, it is an exothermic process.
Views: 348333 Tyler DeWitt
Writing Formulas with Polyatomic Ions
 
11:21
To see all my Chemistry videos, check out http://socratic.org/chemistry Here's how to write formulas for ionic compounds that contain polyatomic ions. In order to write formulas for polyatomic ions, you have to look at a chart or table of polyatomic ions to find out what the charge of each one is. Then, you figure out how many other ions will be necessary to balance out the charges and make it neutral.
Views: 1139014 Tyler DeWitt
Hydrogen Bonding and Common Mistakes
 
09:00
To see all my Chemistry videos, check out http://socratic.org/chemistry Hydrogen bonding can be so confusing, and in this video we talk about some common mistakes. Hydrogen bonds are intermolecular forces between molecules. They form because one atom has a high electronegativity, so it gets a partial negative charge, and the hydrogen gets a partial positive charge.
Views: 492187 Tyler DeWitt
Isotopes and Elements Practice Problems
 
06:39
To see all my Chemistry videos, check out http://socratic.org/chemistry In this video we'll look at how to determine, calculate and solve for atomic number, mass number, isotopes, net charge, protons, neutrons, and electrons. We'll determine what element an atom is by using the periodic table.
Views: 216291 Tyler DeWitt
Nuclear Half Life: Intro and Explanation
 
05:53
To see all my Chemistry videos, check out http://socratic.org/chemistry Nuclear half life is the time that it takes for one half of a radioactive sample to decay. In this video, we will learn the basics of nuclear half life, and examine graphs and practice problems.
Views: 286121 Tyler DeWitt
How to Balance Redox Equations in Acidic Solution
 
15:00
We'll go step by step through how to balance an oxidation reduction (redox) reaction in acidic solution. Most importantly, both charges and atoms must balance. Here are the steps: first, calculate oxidations numbers for all the elements in the equation. Next, figure out what is being oxidized and what is being reduced. Then, write half reactions for the oxidation and reduction. After that, balance each half reaction: first, for the atoms other than O and H, then for O and H, and finally for charge by adding electrons. After being balanced, the oxidation and reduction half reactions are ready to be added back to together. Make sure that the number of electrons is the same in the oxidation and reduction half reactions. If they are not, multiply one or both of the half reactions to make the number of electrons the same. Then, combine the oxidation and reduction half reaction, canceling out stuff that appears on both sides of the equation. Lastly, do a final check to make sure that everything balances: both atoms and charge.
Views: 519820 Tyler DeWitt
Charge of an Electron: Millikan's Oil Drop Experiment
 
12:53
To see all my Chemistry videos, check out http://socratic.org/chemistry How did scientists discover how much negative charge an electron had? Robert Millikan and Harvey Fletcher used the oil drop experiment. They looked an tiny droplets of oil, and balanced the downward gravitational (gravity) force with an upward electrical force. At this point, they knew the forces had to equal, and they calculate the charge on the oil drops.
Views: 246995 Tyler DeWitt
Discovery of the Electron: Cathode Ray Tube Experiment
 
11:08
To see all my Chemistry videos, check out http://socratic.org/chemistry J.J. Thompson discovered the electron, the first of the subatomic particles, using the cathode ray tube experiment. He found that many different metals release cathode rays, and that cathode rays were made of electrons, very small negatively charged particles. This disproved John Dalton's theory of the atom, and Thompson came up with the plum pudding model of the atom.
Views: 487055 Tyler DeWitt
Scientific Notation: Addition and Subtraction
 
07:12
To see all my Chemistry videos, check out http://socratic.org/chemistry Explains how to add and subtract numbers written in scientific notation, whether or not they have the same exponent.
Views: 578302 Tyler DeWitt
What's the Difference between Mass Number and Atomic Mass?
 
08:57
To see all my Chemistry videos, check out http://socratic.org/chemistry What's the difference between mass number and atomic mass? Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units. Atomic mass is the average mass of all the isotopes of a certain type. It is a weighted average that takes into account the abundances of all of the different isotopes.
Views: 273789 Tyler DeWitt
Ionic Bonding Part 2
 
10:18
To see all my Chemistry videos, check out http://socratic.org/chemistry We'll look at the details of ionic bonding, using sodium chloride as an example. Both atoms have unfilled valence shells, which are the outermost energy level. Electrons are transferred from the metal to the nonmetal, creating ions with an opposite charge. The atoms are then held together because of the attraction between the opposite charges.
Views: 432483 Tyler DeWitt
Naming Acids Introduction
 
13:12
How do you name acids? We'll learn how to look at the chemical formula for an acid and then write its name. We will focus on both acids without oxygen and also acids that contain oxygen, which are sometimes called oxoacids. In order to name an acid, you need separate the H+ from the negative ion. Then you figure out the name of the negative ion, and use rules for acid compound naming. If the negative ion ends in -ide, the acid is hydro- -ic acid. If the negative ion ends in -ate, the acid is -ic acid. If the negative ion ends in -ite, the acid is -ous acid. It's also important to note that there are some exceptions: phosphoric acid, phosphorous acid, sulfuric acid and sulfurous acid.
Views: 660163 Tyler DeWitt
Naming Covalent Molecular Compounds
 
10:46
We'll learn how to write names for compounds that are made of two nonmetals, sometimes called binary compounds. Binary compounds made of two nonmetals are called covalent or molecular because the elements are held together with covalent bonds, and they make molecules. In order to name them, we use the element name for the first element in the chemical formula, and then we use the -ide name for the second name in the chemical formula. Greek prefixes to show the number of atoms of each element, and these are put in front of the element names.
Views: 600569 Tyler DeWitt
Limiting Reactant Practice Problem
 
10:47
We'll practice limiting reactant and excess reactant by working through a problem. These are often also called limiting reagent and excess reagent. The limiting reactant or the limiting reagent is the first reactant to be used up during a chemical reaction. Once the limiting reactant or limiting reagent is used up, no more product can form. In order to solve stoichiometry problems with limiting reactant or limiting reagent, we need to figure out which of the reactants is the limiting reactant or limiting reagent. Then, we see how much product can be formed by using the maximum amount of the limiting reactant or limiting reagent. The excess reactant or excess reagent is what is left over after all of the limiting reactant or limiting reagent has been used up.
Views: 516724 Tyler DeWitt
Scientific Notation and Significant Figures (1.7)
 
07:58
To see all my Chemistry videos, check out http://socratic.org/chemistry How to round with significant figures when you're doing scientific notation problems.
Views: 580637 Tyler DeWitt
Discovery of the Nucleus: Rutherford's Gold Foil Experiment
 
15:59
To see all my Chemistry videos, check out http://socratic.org/chemistry In 1911, Ernest Rutherford and his colleagues discovered the nucleus of the atom using their famous gold foil experiment. They shot alpha particles at a sheet of gold foil, and noticed that most went through, but some bounced back. This showed that atoms have a nucleus, and it disproved Thompson's plum pudding model of the atom.
Views: 317529 Tyler DeWitt
Super Common Mistake: Diatomic Elements
 
04:24
Shouldn't there be two atoms of every diatomic element? Many students get confused by the diatomic elements. Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine always form diatomic molecules and pair up. You don't find just one atom of a diatomic element on its own. But then, why do many chemical formulas like H2O and LiBr, have just one atom of a diatomic molecule? We talk about this super common mistake and misconception.
Views: 49963 Tyler DeWitt
Classifying Types of Chemical Reactions Practice Problems
 
05:48
Here are many example equations, so you can get lots of practice classifying them into the major types of chemical equations. In the video, we'll look at examples of synthesis, decomposition, combustion, single replacement and double replacement. The last two reactions are sometimes referred to as single displacement and double displacement.
Views: 279692 Tyler DeWitt
Why are Significant Figures Important?
 
07:45
To see all my Chemistry videos, check out http://socratic.org/chemistry What's the point of significant figures?!? Really, significant figures (or significant digits) can be such a pain in the neck. What is the point? Significant figures tell us how to round, but they also make sure that the answer we get from a math problem is not more precise than the numbers that we started with. Accuracy and precision are both important with significant figures and digits.
Views: 109864 Tyler DeWitt
What's the Difference between an Atom and a Molecule?
 
05:17
To see all my Chemistry videos, check out http://socratic.org/chemistry Never be confused by this concept again! In this video, we talk about the difference between an atom and molecule, and discuss the nucleus, energy levels, protons and neutrons, compounds, covalent bonding, sharing electrons, and lego blocks.
Views: 230664 Tyler DeWitt
Tricky Question: Exothermic or Endothermic?
 
03:13
Need help? Ask me your questions here: http://vespr.org/videos/5130b7d29d53443c3bd593c2 Is this process exothermic or endothermic? Actually, it depends on what we consider the system, and what we consider the surroundings. Every process can be exothermic or endothermic, depending on your point of view.
Views: 120520 Tyler DeWitt
Introduction to Balancing Chemical Equations
 
12:23
How to balance chemical equations. We'll start out with examples that show the concepts behind balancing chemical equations. We will start with a word equation, and then write a chemical equations, and then visualize the atoms and molecules and how they change. To figure out if the equations is balanced, we look at the number and type of atoms on each side of the arrow. If the number and type of atom is not the same on both sides, the equation in unbalanced. We need to change the number of one or more of the compounds in order to get the atoms to balance. We do this by placing coefficients (numbers) in front of each of the compounds. When balancing equations, you cannot ever change the subscripts of a compound.
Views: 696350 Tyler DeWitt
Empirical Formula and Molecular Formula Introduction
 
08:31
We will talk about what empirical formula and molecular formula are, how they are different, and we'll learn how to write the empirical formula for a compound when you are given the molecular formula. Molecular formulas tell you how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a compound. If a compound's molecular formula cannot be reduced any more, then the empirical formula is the same as the molecular formula. Also, many compounds with different molecular formula have the same empirical formula.
Views: 707130 Tyler DeWitt
Scientific Notation: Multiplication and Division
 
05:30
To see all my Chemistry videos, check out http://socratic.org/chemistry Explains how to multiply and divide numbers that are written in scientific notation.
Views: 448890 Tyler DeWitt
Ideal Gas Law: Where did R come from?
 
03:32
To see all my Chemistry videos, check out http://socratic.org/chemistry You can find the number for R in any textbook, but where did it come from in the first place? In this video, we show how to derive the universal gas constant used in the ideal gas law.
Views: 72961 Tyler DeWitt
Writing Ionic Formulas: Practice Problems
 
03:42
To see all my Chemistry videos, check out http://socratic.org/chemistry Lots of practice problems for writing formulas of ionic compounds, so you can get really good at this. In order to write an ionic formula, the charges of the positive ion (cation) and the negative ion (anion) have to balance each other out so that the compound is neutral.
Views: 109933 Tyler DeWitt
Counting Atoms: Intro to Moles Part 2
 
10:08
We'll learn how to use moles to figure out how many atoms you have in something. If there are 602 hexillion things in a mole, how do you count them all? By using the periodic table, you can figure out the molar mass, the amount that one mole of a substance weighs. Once you weigh something to determine how many moles are in it by using molar mass, Avogadro's number allows you to figure out how out how many atoms there are.
Views: 322591 Tyler DeWitt
Basic Atomic Structure: A Look Inside the Atom
 
07:45
To see all my Chemistry videos, check out http://socratic.org/chemistry What does the inside of an atom look like? Here, we'll look at the subatomic particles ( protons, neutrons, and electrons) that make up the atom. We'll see how the electrons orbit the nucleus, and talk about the masses of protons, neutrons, and electrons in amu, or atomic mass unit.
Views: 469200 Tyler DeWitt
Writing Ionic Formulas with Transition Metals
 
07:21
We'll learn how to write formulas for ionic compounds that contain transition metals. The transition metals are unique because they are elements are able to make multiple ions with different charges. We use roman numerals to indicate the charge of a transition metal ion. To write a formula for an ionic compound with transition metals, we make sure that the positive charge of the cation and the negative charge of the anion balance out. For background on this video, check out: Writing Ionic Formulas Introduction: http://www.youtube.com/watch?v=URc75hoKGLY Transition Metals in Ionic Formulas: http://www.youtube.com/watch?v=Da_ah6TqAss
Views: 185959 Tyler DeWitt
Introduction to Limiting Reactant and Excess Reactant
 
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Limiting reactant is also called limiting reagent. The limiting reactant or limiting reagent is the first reactant to get used up in a chemical reaction. Once the limiting reactant or limiting reagent gets used up, the reaction has to stop and cannot continue. After the limiting reactant or limiting reagent is used up and the reaction stops, there is extra of the other reactants left over. Those are called the excess reactants. In this video, we'll first learn about limiting reactant and limiting reagent by comparing chemical reactions to cooking recipes. We'll look at how to calculate limiting reactant and limiting reagent using cooking ingredients, and then looking at an actual stoichiometry problem,
Views: 958402 Tyler DeWitt
Combined Gas Law
 
06:48
To see all my Chemistry videos, check out http://socratic.org/chemistry Discusses how to solve problems with the Combined Gas Equation.
Views: 294951 Tyler DeWitt