This is the reference sheet given for exams and quizzes You do not need to memorize any components in this sheet but do know how to read and refer to it. - Alyssa R 1/2021

Equations & Periodic Table.pdf

Conversions Chart

This is not given on exams or quizzes. However, it may be a useful sheet when doing homeowrk on dimensional analysis and stoichiometry. - Alyssa R 1/2021

Conversion chart.pdf

OpenStax Textbook for General Chemistry

Chemistry 2e - OpenStax

Significant Figures and Why it's Significant

Sigfigs are important for assessing precision and accuracy in a scientific setting. It tells us how certain and uncertain we are in a measured value.

1. All non-zero numbers ARE significant

2. Zeros between two non-zero digits ARE significant. 2051 has FOUR significant figures. The zero is between a 2 and a 5.

3. Leading zeros are NOT significant. They're nothing more than "place holders." The number 0.54 has only TWO significant figures. 0.0032 also has TWO significant figures. All of the zeros are leading.

4. Trailing zeros to the right of the decimal ARE significant. There are FOUR significant figures in 92.00.

92.00 is different from 92: a scientist who measures 92.00 milliliters knows his value to the nearest 1/100th milliliter; meanwhile his colleague who measured 92 milliliters only knows his value to the nearest 1 milliliter. It's important to understand that "zero" does not mean "nothing." Zero denotes actual information, just like any other number. You cannot tag on zeros that aren't certain to belong there.

5. Trailing zeros in a whole number with the decimal shown ARE significant. Placing a decimal at the end of a number is usually not done. By convention, however, this decimal indicates a significant zero. For example, "540." indicates that the trailing zero IS significant; there are THREE significant figures in this value.

6. Trailing zeros in a whole number with no decimal shown are NOT significant. Writing just "540" indicates that the zero is NOT significant, and there are only TWO significant figures in this value.

7. Exact numbers have an INFINITE number of significant figures. This rule applies to numbers that are definitions. For example, 1 meter = 1.00 meters = 1.0000 meters =

8. For a number in scientific notation: N x 10x, all digits comprising N ARE significant by the first 6 rules; "10" and "x" are NOT significant. 5.02 x 104 has THREE significant figures: "5.02." "10 and "4" are not significant.

- Alyssa R 1/2021

Fast Eeview of Sigfigs

Covers each sigfig rules plus how to add/subtract and multiply/divide with sigfigs. - Alyssa R 1/2021

Sigfigs.pdf

Practice

Put your knowledge to the test with this practice worksheet! Answers can be given by a tutor. - Alyssa R 1/2021

Polyatomic Ions

Want to get to know your polyatomic ions? We have a good resource for you! Check out this quizlet.

https://quizlet.com/58319483/polyatomic-ions-flash-cards/

Added by: Emma Andrade

Updated by Magdalena Hoskins, Spring 2025

Periodic Table Trends

Chemical Reactivity: Metals
- - down a group reactivity increases due to increase of electron shells, making it easier for electrons to be given or taken away
  - across a period reactivity decreases as it is less likely to give away electrons due to it being closer to completing the octet rule and gaining stability

Practice Problems:

For each of the following pair of atoms, determine which is larger and explain why. Draw a picture of the shells if needed.

Carbon or Oxygen? Lithium or Bromine? Magnesium or Calcium?

For each of the following pair of atoms, determine which can lose an electron easier and explain why. (Is this a lower or higher ionization energy?)

Hydrogen or Helium? Boron or Aluminum?

Ionization Energy: the energy needed to remove an electron
- - down a group decreases as valence electrons are farther from the nucleus, thus less pulling power by the protons and less energy needed to remove an electron
  - across a period increases as the atoms are getting closer to the octet rule (Gaining stability like a Noble Gas)
Atomic Radius
- - down a group increases as each next period has additional electron shells, each farther away from the pull of the protons
  - across a period decreases as there are more protons to pull electrons in the shells closer
Electron Affinity: energy to attract electrons
- - down a group decreases as there is less attraction towards electrons due to greater amount of shells, which are father away from the proton pull
  - across a period increases as wants to complete the octet rule and gain stability
Electronegativity: attraction between the nucleus and electrons of the atom
- - down a group decreases as valence electrons are farther from protons in the nucleus
  - across a period increases as the number of protons in the nucleus increases

Stoichiometry Map

Don't know how to convert from grams of substance A to atoms of substance B? Here's a diagram that should help:

-- Alyssa R 2/2021

Dimensional Analysis

Converting from one unit to another:

Example The density of mercury is 13.6 g/mL. What is the mass in kilograms of a 2 L commercial flask of mercury?

First, write down your given and what your goal unit is. Next, you are going to have to figure out what conversion factors you need to get from your given to your goal -- this will vary. Knowing what to use is a skill that you will need to practice. Don't be discouraged if it takes awhile!

More practice in our google drive and here.

- Alyssa R 2/2021

Bonding and Chemical Interactions

Have trouble distinguishing types of bonds and determining molecular geometry of compounds? Here's a brief diagram, examples, and practice problems to help:

Added by Dilpreet Sekhon (Spring 2021)

Converting to Moles

One of the most important topics in chemistry is conversions, especially of atoms, grams, and moles. This video will take you through examples that you will not only teach you, but you can also practice at the same time. At the end of the video answer:

How many moles is 14g of carbon?
How many atoms is 2 moles of carbon?

Edited by Viktor Kunder, chemistry tutor, 01/12/2018

Net Ionic Equations

This video gives overview of how to write net ionic equations step by step. It is recommended you watch the video above (Writing ionic formulas) before watching this! Take notes!!

Test yourself:

Write net ionic equations for:

Magnesium nitrate and strontium chloride
Magnesium nitrate and lithium sulfate

-Added by Preet Kaur (Fall 2020)

Introduction to Buffer Solutions

This video gives an introduction to Buffer Solutions, the Henderson-Hasselbalch equation, and how it is derived.

Added by: Emma Andrade

Intermolecular Forces

This video gives you a brief introduction of intermolecular forces i.e. Hydrogen Bonding, Dipole-Dipole, Ion-Dipole, London Dispersion Interactions.

Added by: Preet Kaur (spring 2021)

Units of the Rate Constant

Units of the rate constant (video) | Khan AcademyThe units of the rate constant, k, depend on the overall reaction order. The units of k for a zero-order reaction are M/s, the units of k for a first-order reaction are 1/s, and the units of k for a second-order reaction are 1/(M·s).

Molecular Shapes

Struggling to remember the molecular structures and shapes of compounds? Here is a video to help out!

Added by: Emma Andrade

Gibbs Free Energy

This video provides a basic introduction into Gibbs Free Energy, Entropy, and Enthalpy. It explains how to calculate the equilibrium constant K given the standard free energy change of a reaction and so much more.

Added by: Preet Kaur (Spring 2021)

Chemical Equilibrium- Ice tables, Constant K

This chemistry video tutorial provides a basic introduction into how to solve chemical equilibrium problems. It explains how to calculate the equilibrium constant k value given the equilibrium concentrations and equilibrium partial pressures of all reactants and products. If explains how to calculate the equilibrium constant k for a new reaction by changing another reaction. Finally, it discusses how to calculate the equilibrium constant k using ice tables.

Added by: Preet Kaur (Spring 2021)

Electron Configurations of the 3d Transition Metals

Electron configurations of the 3d transition metals (video) | Khan AcademyThe Aufbau principle predicts that the 4s orbital is always filled before the 3d orbitals, but this is actually not true for most elements! From Sc on, the 3d orbitals are actually lower in energy than the 4s orbital, which means that electrons enter the 3d orbitals first. In this video, we’ll discuss this in more depth and walk through all of the electron configurations for the 3d transition metals.

Electron Configurations of the 3d Transition Metals Readable Website

Here at the learning center we realize that students have different ways of learning. If videos don't seem to help, maybe a readable website will!

Click on the description to the left and it will take you to a website with a thorough explanation of the 3D transition metals.

Added by: Emma Andrade

Vapor Pressure

Vapor pressure (video) | States of matter | Khan AcademyVapor pressure, volatility, and evaporation.

Here is a video that describes vapor pressure! It offers perspectives and applications that you may not have thought about before! Give this video a watch.

Added by: Emma Andrade

Buffer Solutions

This chemistry video tutorial explains how to calculate the pH of a buffer solution using the henderson hasselbalch equation. It explains the concept, components, and function of a buffer solution. A buffer solution consist of a weak acid and its conjugate weak base counterpart. It's purpose is to maintain a relatively constant pH value. This video discusses the relationship between the pH and pKa values with the relative amounts of weak acid and weak base components in the buffer solution. This video contains plenty of examples and practice problems.

Added by Preet Kaur (Spring 2021)

Molecular Orbital theory

This chemistry video tutorial provides a basic introduction into molecular orbital theory. It describes the formation of bonding and antibonding molecular orbitals from the combination of atomic orbitals. It explains how to calculate the bond order of homonuclear diatomic molecule as well as heteronuclear diatomic molecules. It also contains examples and practice problems of homonuclear and heteronuclear molecular ions.

Added by Preet Kaur (Spring 2021)

Quantum Numbers

This video explains s, p, d, and f orbitals, sublevels, and their shapes. It discusses the 4 quantum numbers n, l, ml, and ms. n represents the energy level, l is associated with the sublevel, ml represents the orbital and ms is the electron spin. It also shows you how to find the 4 quantum numbers for an electron and how to write the electron configuration in addition to how to write the orbital notation or fill in the arrows in the orbital diagram for an element. In addition, this video discusses the principles of Hund's Rule, Pauli's exclusion principle, and the Aufbau principle.

Added by: Emma Andrade

Phase Diagrams

Here is a cool video explaining phase diagrams, critical points, etc!

Phase diagrams are a graph that relates the pressure and temperature of a substance to the state of matter (solid, liquid or gas).

Added by: Emma Andradeas)

Hybridization

This organic chemistry video tutorial explains the hybridization of atomic orbitals. It discusses how to determine the number of sigma and pi bonds in a molecule as well determining if a carbon is sp, sp2, or sp3 hybridized.

Added by Preet Kaur (Spring 2021)

Freezing Point Depression and Boiling Point Elevation

Boiling point elevation and freezing point depression (video) | Khan AcademyBoiling point elevation is the raising of a solvent's boiling point due to the addition of a solute. Similarly, freezing point depression is the lowering of a solvent's freezing point due to the addition of a solute. In fact, as the boiling point of a solvent increases, its freezing point decreases. An example of this would be the addition of salt to an icy sidewalk. The solute (salt) reduces the freezing point of the ice, which allows the ice to melt at a lower temperature.

Freezing Point Depression and Boiling Point Elevation (Readable Version)

Take a look at this cool website that explains solutions and how the freezing and boiling point change!

Added By: Emma Andrade

Integrated Rate Laws

Here is a nice video illustrating the different integrated rate laws along with the graphs associated with each.

Added by: Dilpreet Sekhon

Le Chatelier's Principle

Here is a nice video illustrating Le Chatlier's principle along with examples to test your understanding.

Added by: Dilpreet Sekhon (September 2022)

Titrations

Here is a nice video illustrating acid-base titrations and how to find the pH for weak acids and bases.

Added by: Dilpreet Sekhon (November 2022)

Absolute and Percent Error

Need help calculating absolute/percent error? Check this video out! - Ali D, Abbas D, Mahek P 02/2023

Standard Deviation By-Hand

Calculating standard deviation by-hand is pretty tough right? Look at this excellent video! - Ali D, Abbas D, Mahek P 02/2023

Standard Deviation on Excel

Check this video out to get familiar with calculating standard deviation on Excel!

- Ali D, Abbas D, Mahek P 02/2023

Naming Ionic Compounds

This video goes over naming binary ionic compounds, particularly transition metals, and how to notate their charges in Roman numerals.

- Dilpreet S., Daniel H., Sirat K. 03/2023

Dimensional Analysis

This video goes over dimensional analysis. Specifically on converting, with examples.

-Daniel H., Dilpreet S. 09/2023

CHEM 2023-09 Chemistry 1A Lab #1 Guide.mp4

Chem 1A Lab #1 Guide

Struggling with your first lab in CHEM 1A? Watch this video! It will cover the basics and get you ready for your first lab!

Report abuse