View source for Chemistry Lab

{{Infobox event
    | active        = yes
    | type          = Chemistry
    | cat           = Lab
    | eventtime     = 50 minutes
    | impound       = No
    | eyeprotection = C
    | resources     = * Safety equipment
* Writing utensil
* One stand-alone calculator
* One standard sheet of paper
    | rotates       = No, only topics
    | description   = Teams will complete one or more tasks and answer a series of questions involving the science processes of chemistry focused in the areas of Oxidation/Reduction and Periodicity. 
    | 2009thread    = [http://www.scioly.org/phpBB3/viewtopic.php?f=18&t=208 2009]
    | 2010thread    = [http://www.scioly.org/phpBB3/viewtopic.php?f=65&t=1282 2010]
    | 2011thread    = [http://scioly.org/phpBB3/viewtopic.php?f=92&t=2206 2011]
    | 2012thread    = [http://scioly.org/phpBB3/viewtopic.php?f=127&t=2949 2012]
    | 2013thread    = [http://www.scioly.org/phpBB3/viewtopic.php?f=142&t=3725 2013]
    | 2014thread    = [http://www.scioly.org/phpBB3/viewtopic.php?f=166&t=4953 2014]
    | 2015thread    = [http://scioly.org/phpBB3/viewtopic.php?f=186&t=5913 2015]
    | 2016thread    = [http://scioly.org/phpBB3/viewtopic.php?f=207&t=7701 2016]
    | 2017thread    = [http://scioly.org/phpBB3/viewtopic.php?f=226&t=9286 2017]
    | 2018thread    = [https://scioly.org/forums/viewtopic.php?f=264&t=10861 2018]
    | 2019thread    = [https://scioly.org/forums/viewtopic.php?f=284&t=12128 2019]
    | 2020thread    = [https://scioly.org/forums/viewtopic.php?f=284&t=15361 2020]
    | 2021thread    = [https://scioly.org/forums/viewtopic.php?f=347&t=18275 2021]
    | 2022thread    = [https://scioly.org/forums/viewtopic.php?f=385&t=23502 2022]
    | 2023thread    = [https://scioly.org/forums/viewtopic.php?t=26045 2023]
    | testid        =
    | 2015questions = [http://scioly.org/phpBB3/viewtopic.php?f=193&t=6283 2015]
    | 2016questions = [http://scioly.org/phpBB3/viewtopic.php?f=217&t=7771 2016]
    | 2017questions = [http://scioly.org/phpBB3/viewtopic.php?f=228&t=9650 2017]
    | 2018questions = [https://scioly.org/forums/viewtopic.php?f=266&t=11168 2018]
    | 2019questions = [https://scioly.org/forums/viewtopic.php?f=297&t=12477 2019]
    | 2020questions = [https://scioly.org/forums/viewtopic.php?f=324&t=18351 2020]
    | 2021questions = [https://scioly.org/forums/viewtopic.php?f=297&t=19713 2021]
    | 2022questions = [https://scioly.org/forums/viewtopic.php?f=387&t=23460 2022]
    | 2023questions = [https://scioly.org/forums/viewtopic.php?t=26062 2023]
    | 1stCName      = Montgomery High School
    | 2ndCName      = New Trier High School
    | 3rdCName      = Adlai E. Stevenson High School
    | Website       = https://www.soinc.org/chem-lab-c}}
'''Chemistry Lab''' is an event where participants must learn the year's selected aspects of chemistry and perform a lab or a set of labs regarding those topics.

Since this event rotates topics, each topic constitutes its own page. For topic-specific information, please see [[Chemistry Lab#Topic Rotation|the topic rotation]], as this page only contains general information that applies to all topics.

Chemistry Lab has been held every year in Division C since 1987.

== Topic Rotation ==
Chemistry Lab typically rotates between several topic area, with two topics at a time, and one topic rotating in/out each year.

{| class="wikitable" style="margin-top:0;"
|-
!Season
!Topic(s)
|-
![[2023]]
|[[Chem Lab/Electrochemistry|Redox Reactions]], [[Chem Lab/Periodicity|Periodicity]]
|-
![[2022]]
|[[Chem Lab/Aqueous Solutions|Aqueous Solutions]], [[Chem Lab/Electrochemistry|Redox Reactions]]
|-
![[2021]]
|[[Chem Lab/Aqueous Solutions|Aqueous Solutions]], [[Chem Lab/Acids and Bases|Acids and Bases]]
|-
![[2020]]
|[[Chem Lab/Aqueous Solutions|Aqueous Solutions]], [[Chem Lab/Acids and Bases|Acids and Bases]]
|-
![[2019]]
|[[Chem Lab/Acids and Bases|Acids and Bases]], [[Chem Lab/Physical Properties|Physical Properties]]
|-
![[2018]]
|[[Chem Lab/Physical Properties|Physical Properties]], [[Chem Lab/Thermodynamics|Thermodynamics]]
|-
![[2017]]
|[[Chem Lab/Thermodynamics|Thermodynamics]], [[Chem Lab/Gas Laws|Gas Laws]]
|-
![[2016]]
|[[Chem Lab/Gas Laws|Gas Laws]], [[Chem Lab/Kinetics|Kinetics]]
|-
![[2015]]
|[[Chem Lab/Kinetics|Kinetics]], [[Chemistry Lab#Stoichiometry|Stoichiometry]]
|-
![[2014]]
|[[Chemistry Lab#Stoichiometry|Stoichiometry]], [[Chem Lab/Equilibrium|Equilibrium]]
|-
![[2013]]
|[[Chem Lab/Equilibrium|Equilibrium]], [[Chem Lab/Periodicity|Periodicity]]
|-
![[2012]]
|[[Chem Lab/Periodicity|Periodicity]], [[Chem Lab/Electrochemistry|Electrochemistry]]
|-
![[2011]]
|[[Chem Lab/Electrochemistry|Electrochemistry]], [[Chem Lab/Aqueous Solutions|Aqueous Solutions]]
|-
![[2010]]
|[[Chem Lab/Aqueous Solutions|Aqueous Solutions]], [[Chem Lab/Kinetics|Kinetics]]
|-
![[2009]]
|[[Chem Lab/Acids and Bases|Acids and Bases]], [[Chem Lab/Titration Race|Titration Race]]
|-
![[2008]]
|[[Chemistry Lab#Stoichiometry|Chemical Reactions]], Energy
|-
![[2007]]
|Nuclear Chemistry, [[Chem Lab/Gas Laws|Gas Laws]]
|-
![[2006]]
|[[Chem Lab/Thermodynamics|Thermodynamics]], [[Chem Lab/Physical Properties|Physical Properties]]
|-
![[2005]]
|Chemical Bonding, [[Chem Lab/Electrochemistry|Redox Reactions]]
|-
![[2004]]
|[[Chem Lab/Periodicity|Periodicity]], [[Chem Lab/Electrochemistry|Redox Reactions]]
|-
![[2003]]
|[[Chem Lab/Kinetics|Kinetics]], [[Chem Lab/Periodicity|Periodicity]]
|-
![[2002]]
|[[Chem Lab/Kinetics|Kinetics]], [[Chem Lab/Aqueous Solutions|Aqueous Solutions]]
|-
![[2001]]
|[[Chem Lab/Aqueous Solutions|Aqueous Solutions]]
|-
|
|
|-
![[1999]]
|Energy in Chemical and Physical Changes
|}


== Description==
As of 2019, the following materials are allowed:

*[[Safety Glasses#Category C|Category C Eye Protection]] (Required)
*Lab coat, closed-toed shoes, etc.—see rule 2.c for exact safety parameters (Required)
*1 double-sided [[Note Sheets|note sheet]] per team (sheet protectors and lamination allowed)
*1 stand-alone, non-graphing, non-programmable [[Calculators|calculator]] per student

==General Chemistry==
:''This section includes general chemistry knowledge that is applicable to most or all topics. For information on specific topics, see the section on [[Chemistry Lab#Topic Rotation|Chemistry Lab Topics]].''

===Periodic Table===
{{Main|Chem Lab/Periodicity}}
[[File:Periodic table.png|thumb|600px|center|The Periodic Table (Click to expand for more detail)]]
The periodic table of the elements organizes the known elements by properties.

They are numerically ordered by their atomic number, which is the number of protons in the nucleus of an atom. The elements are arranged so they are in columns with similar chemical properties. These columns are called groups. Rows are called periods, and display properties known as periodicity.

===Stoichiometry===
The Merriam-Webster dictionary defines stoichiometry as "a branch of chemistry that deals with the application of the laws of definite proportions and of the conservation of mass and energy to chemical activity". Stoichiometry deals with calculations about the masses (sometimes volumes) of reactants and products involved in a chemical reaction. It is a very mathematical part of chemistry. The most common stoichiometric problem will present you with a certain amount of a reactant and then ask how much of a product can be formed. For example, a problem might provide the equation 2''A'' + 3''B'' → 3''C'' and ask, "given 25 grams of ''B'' and unlimited amount of ''A'', how much ''C'' will be produced?" This is called a mass-mass problem. These problems can be solved in 4 simple steps.

#Make sure the chemical equation is correctly balanced.
#Using the molar mass of the given substance, convert the mass given in the problem to moles.
#Construct a molar proportion (two molar ratios set equal to each other) following the guidelines set out in other files. Use it to convert to moles of the unknown.
#Using the molar mass of the unknown substance, convert the moles just calculated to mass.

Other forms of stoichiometric problems are finding the limiting reactant and finding the percentage composition. You can find out more about these in the links below.

The process is very similar when given gases (using the ideal gas law), solutions (using molarity) or molecules (using Avogadro's number)

Stoichiometry can be approached in precisely the same way one would approach dimensional analysis. And, when in doubt, convert to moles.

===Reaction Types===
There are five main types of reactions (single displacement, double displacement, decomposition, synthesis, and combustion). Each of them has a specific form that they take. If you encounter problems dealing with reactions on the test, knowing the basic types can be very helpful because then you will be more likely to see the pattern and understand how to complete the reaction.

====Single Displacement====
[[File:Single replacement.JPG|thumb|right|300px|An example of a single replacement reaction. Here, copper reacts in silver nitrate solution to form copper nitrate solution and silver metal. The copper nitrate solution is visible since copper cations are blue in solution.]]

Also called '''single replacement reactions'''. Single displacement reactions are oxidation-reduction reactions in which an element and a compound react to form another element and a compound. This reaction takes on the form

:''A'' + ''BC'' → ''AC'' + ''B''

So the lone elemental reactant, A, forms a compound with C, forcing B out to become an element itself. In order for this to occur, A and B are usually metals that form a cation when compounded with C.

The direction in which the reaction proceeds depends on each element's position in the [[Chem Lab/Electrochemistry#Activity Series|activity series]]. A has to be more likely to oxidize than B, because otherwise B will just simple stay in solution and A will remain untouched.

====Double Displacement====
Double displacement reactions are similar to single replacement, but they are usually not oxidation-reduction reactions. Instead of just one element being traded, double displacement reactions have two similarly formed compounds reacting to form other compounds.

:''AB'' + ''CD'' → ''AD'' + ''CB''

This type of reaction is especially important in aqueous solutions, since most precipitation reactions are double displacement reactions. Precipitation occurs when AB and CD are both soluble in water, and when put together, either AD or BC is an insoluble compound and thus precipitates out of the solution. For more information about solubility, see [[Chem Lab/Aqueous Solutions]].

====Decomposition====
In decomposition, a compound decomposes into its constituent parts.

:''AB'' → ''A'' + ''B''

This type of reaction usually occurs when the compound AB is unstable, since breaking a chemical bond requires energy. Since it takes energy to break a bond, the vast majority of decomposition reactions are endothermic.

====Synthesis====
Synthesis reactions are the opposite of decomposition reactions. These reactions have two elements or components bonding together to form a larger compound.

:''A'' + ''B'' → ''AB''

Since this reaction forms a bond, it is exothermic.

==== Combustion====
Combustion reactions are reduction-oxidation reactions (also called ''redox'' reactions) involving oxygen or another oxidizing agent. Combustion reactions are also exothermic reactions since they give off heat. The most common combustion reactions form carbon dioxide, water, and energy. For example, here is the combustion reaction for methane:

:CH<sub>4</sub> + 2O<sub>2</sub> → CO<sub>2</sub> + 2H<sub>2</sub>O + energy

Combustion can also occur with nitrogen instead of carbon. There is also combustion with only hydrogen and oxygen, and in this case only water forms as product.

:2H<sub>2</sub> + O<sub>2</sub> → 2H<sub>2</sub>O + energy

Since combustion reactions are among the most common exothermic reactions, it is a good idea to know the combustion reactions of several important compounds, or at least know how to go about finding it quickly. Since all of them have a similar form, you can guess what the products will be, which will make it easier. For example, for the combustion of a hydrocarbon in oxygen, the two products will be water and carbon dioxide, since the oxygen attaches itself to both carbon and hydrogen parts.

===Oxidation and Reduction===
{{Main|Chem Lab/Electrochemistry}}
Oxidation and reduction reactions are those where reactants see a net gain or loss of electrons. Typically, losses and gains occur in pairs, with the electrons lost in one chemical species being gained by another. To remember which is which, it may be helpful to use the acronym '''OIL RIG''', or ''Oxidation is Loss, Reduction is Gain''. This is a simple way of remembering that whatever is oxidized loses electrons and whatever is reduced gains electrons. The phrase '''LEO the lion says GER''' also works, which refers to "Lose Electrons-Oxidation; Gain Electrons-Reduction."

===Aqueous Solutions===
{{Main|Chem Lab/Aqueous Solutions}}
An aqueous solution is a solution where the solute is dissolved in water.

===Equilibrium===
{{Main|Chem Lab/Equilibrium}}
Equilibrium refers to properties of chemical solutions which respond to changes in concentration (as well as other factors such as temperature).

===Thermodynamics===
{{Main|Chem Lab/Thermodynamics}}
:''See also, the page for the separate event [[Thermodynamics]].''
Thermodynamics is the study of the interaction of energy transfer and systems of matter.

===Acids and Bases===
{{Main|Chem Lab/Acids and Bases}}
Acids and bases are two complementary classes of substances displaying unique properties, most notably the production of H<sup>+</sup> ions (for acids) and OH<sup>-</sup> ions (for bases) in solution.

=== Titrations===
{{Main|Chem Lab/Titration Race}}
A titration is a controlled chemical procedure that involves adding a known amount of one substance, typically in solution (the titrant) to another solution, typically until neutralization. This is frequently done with acids and bases.

===Gas Laws===
{{Main|Chem Lab/Gas Laws}}
Gas Laws refer to the chemical and thermodynamic laws governing the physical behavior of and reactions involving gases.

== Event Strategy==
Like all events, Chem Lab requires a strategy for you to be able to do your best.

*It is very helpful if one or both partners has taken AP Chemistry, since some of the topics covered in this event are advanced and not covered in normal high school chemistry classes.
*Try to split the work between you and your partner so that in studying, you can cover both topics.
*If you get a longer test, ask if you can remove the staple and split the test, so that you can cover more of the test in less time.
*Try to arrange your team so that you have one person who is good at quickly performing labs and one person who is good at computations and writing. This should facilitate the labs.
* Make sure to work not just quickly, but efficiently, on the labs. Do them as quickly as you can, but if you end up with inaccurate results then going quickly didn't help you a whole lot. Also, do not take shortcuts unless you are absolutely, positively sure you can.
*Make sure you have all of your protective equipment, as you may be disqualified if you do not have it.

==Links==
*[http://users.erols.com/merosen/stoichio.htm Stoichiometry links]
*[http://members.tripod.com/~Air_Piglet/ApChem.htm Study for the AP Chem test]
*[http://www.chem.wisc.edu/~concept/ Some Chemistry tests]
*[[Media:Solubility Rules.pdf|Solubility rules and evolved gases list for aqueous systems]]
*[http://www.youtube.com/watch?v=jefaZdCy8fM&feature=related Chem lab video: oxidation/reduction]
*[[Media:Inf flat Chem Notes.pdf|Infinity Flat's Chem Notes 1]]
*[[Media:Inf flat Chem Notes 2.pdf|Infinity Flat's Chem Notes 2]]
*[https://docs.google.com/document/d/13DfQgyzuYdG6OfOO_crwTFBtFy65P50_c8rAIjJKepo/edit Bay Area students' guide to Chemistry Lab]

{{Chemistry Lab}}
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