Level I Chemistry Events

A maximum of three team members may participate in each event. Also see other events for both Level I and Level II teams listed at the end.

Reactions in Action

A variety of equations will be completed and balanced and types of chemical reactions will be identified by each team.
Advance Preparation: None, except for any desired practice.

The Event:

Given reactants either by names or formulas, and sometimes products, each team will be challenged to write within 30 minutes a number of balanced equations. The balancing method(s) can be freely selected by the team–only the results matter. The teams will also be asked to identify some of the equations by reaction type (for example: single replacement, double replacement, composition/synthesis, decomposition, combustion, neutralization). A list of possible reaction types will be provided. Notes are not allowed.

The team with the greatest number of correct, complete, and balanced equations, and correct identifications will be declared the winner.

Concurrent event is Weighing by Redox.

Hydronium Hijinks

The concentration of a strong, monoprotic acid solution provided at the event will be determined.
Advance Preparation: Prior to the Chemathon, the team (with teacher supervision) must prepare 500 mL of approximately 0.1 M sodium hydroxide solution, NaOH(aq). The actual concentration of the basic solution should then be determined (to the nearest 0.001 M or better). This can be accomplished by titrating the base against an acid solution of accurately known concentration, or by titrating the base against a primary standard, a solid acidic substance of known purity and high molar mass. The NaOH solution must be made up and standardized by the team; it cannot be a commercial solution.

The Event:

Using their own standardized basic solution and their own 50-mL burets, team members will determine the concentration (mol/L) of the acid solution provided at the event. Four burets (supplied by the team) will be used: one will be set up by the team to deliver the initial volume of unknown acid solution, the other three burets will be filled with standardized base by the team so that all three team members can conduct independent titrations. As many titrations as desired can be completed with in the 30-minute time limit, recognizing that only 200 mL of the unknown acid solution will be available to the team. No electronic pipets or burets may be used. Notes on calculations or procedures, etc., are not allowed; however, the container of sodium hydroxide solution may be labeled with the concentration.

The team will report only one acid concentration value, in mol/L with an appropriate number of significant digits, for judging. Supporting data and calculations must be provided. The unknown acid solution's concentration will be between 0.05 M and 0.15 M. The team must bring to the Chemathon four 50-mL burets and its standardized sodium hydroxide solution. Other needed supplies will be provided at the event.

The team reporting the mol/L value for the acid solution closest to the "known" value will be declared winner.
Brought by the team:

goggles, aprons, shoes without open spaces
500 mL standardized NaOH solution
phenolphthalein indicator solution
four burets
no electronic pipets or burets may be used
nonprogrammable calculator; pen or pencil
notes on procedures and calculations are not allowed

Provided by Chemathon:

200 mL unknown acid solution
3 250-mL Erlenmeyer flasks
4 ringstands and clamps for burets
beakers, wash bottles, dropper pipets, funnels for filling burets
distilled water
blank paper for calculations
paper towels

Concurrent event is Mendeleev Madness.

Mendeleev Madness

Questions based on the periodic chart will be fielded by the team.
Advance Preparation: None, but a periodic table review might be appropriate. For practice, the team might want to play the following on-line "Element Games":

The Event:

Each team will be given a blank periodic table and a written set of clues regarding the physical or chemical properties of the first 26 Group A elements of the periodic table. (Examples: an atom of element R contains 11 protons. Element X has a lower ionization energy than element D.) Team members will be given 30 minutes to decide on the locations of all coded elements on the blank periodic table. Notes are not allowed; only a pencil or pen is to be brought to the event. One copy of the filled-in periodic table is submitted by the team for judging. All materials must be returned when time is called.

The team's periodic table with the largest number of coded elements correctly placed will be judged the winner.

Concurrent event is Hydronium Hijinks.

Weighing by Redox

The mass of a pre-cut sample of magnesium metal is calculated from data obtained when excess hydrochloric acid is added to the sample, and the volume of wet hydrogen gas is measured at known temperature and pressure.
Advance Preparation: None, except for practice. Locate and test a suitable gas-collecting tube.

The Event:

The team will be given a length of magnesium metal. A 20-mL sample of 2 M hydrochloric acid is poured into an inverted gas-measuring tube; the tube is then filled with distilled water. The magnesium metal sample is held in position near the mouth of the tube with a length of thin copper wire, which is held in place with a one-hole stopper. The tube is then inverted into a partially-filled beaker of water. The hydrogen gas generated is collected by water displacement. From gas law calculations, taking water vapor pressure and the difference in water levels into account, the team calculates the original mass of magnesium metal in the sample, expressed to suitable precision. Supporting data and calculations must be submitted. Hint: it will not be possible to equalize the water levels; the mass of magnesium in the sample will produce between 25 and 45 mL of wet hydrogen gas.

The magnesium sample, hydrochloric acid, distilled water, beaker, ring stand, and a ruler will be provided. The current value of the atmospheric pressure will also be provided, as well as a printed sheet with necessary values (R = 8.3145 dm3 kPa/K mol = 0.082058 L atm/K mol, M(Mg) = 24.3050 g/mol, and a table of water vapor pressures in kPa and mmHg at various temperatures). The team must supply its own gas-collecting tube, thermometer, copper wire, a suitably sized one-hole stopper, and a nonprogrammable calculator. The team may not bring notes for the calculations.

The team reporting the mass of magnesium with the lowest percent error (judged by its previously measured mass) will be declared winner.
Brought by the team:

goggles, aprons, shoes without open spaces
gas-collecting tube, one-hole stopper, copper wire
thermometer
nonprogrammable calculator; pen or pencil
notes on procedures and calculations are not allowed

Provided by Chemathon:

magnesium ribbon sample
2 M hydrochloric acid
50-mL graduated cylinder
beakers, ring stands, clamps, distilled water
plastic ruler
paper towels
data table
blank paper for calulations

Concurrent event is Reactions in Action.

Viscoelastic Bounce

This is a competition involving homemade "silly putty."
Advance Preparation: The team should practice making elastic balls with a recipe similar to the following, using ingredients available in stores: Place a mixture of 25 mL white glue (such as Elmer's) and 20 mL water in a small paper cup or plastic Ziploc-type bag. (The polymer in white glue is polyvinylacetate.) Add 5 mL of a saturated solution of borax (sodium tetraborate), about one level tablespoon per cup of water, and stir or knead well. The ball may be cured with a hair dryer. The team should investigate the effects of changes in ingredient proportions, ball size, etc.

The Event:

Team members may prepare any number of balls from materials and supplies they bring with them. The balls must be prepared during the event using the ingredients (white glue, borax, and water) but not necessarily the amounts given above. One or two balls will be dropped individually (two drops in all) from the height of a lab bench (91 cm). The team making the ball that bounces the highest wins.

Brought by the team:

goggles, aprons, shoes without open spaces
white glue
borax or borax solution
plastic cups or bags
hair dryer (optional)
wash cloths and towels for cleanup (suggested)
notes on procedures are not allowed

Provided by Chemathon:

tap water
board for measuring heights
paper towels