Grade 9 Model project: Balanced equation

QUESTION

Build a model of a molecule (that actually exists) using only the 30 elements that you were taught in grade 8.

The molecule has to consist of more than four atoms.

Please note the following:

• Your molecule has to be made of recycled materials. No polystyrene may be used.

• Different atoms have different sizes – this should be evident in your molecule.

• Your model has to be 3-dimensional, but mounted on a board of some kind.

• Not only do you have to build the molecule, but also the reactants that the molecule comprise of. The entire model has to be a visual representation of a BALANCED equation:

• Provide an equation that utilises elementary symbols and molecular formulae, with the word equation added below.
• Classify the type of reaction: exothermic, endothermic, combustion, neutralisation, and so on.

 

Aspects or criteria	Excellent in all aspects (5)	Good in most aspects (4)	Could be better (2)	NO effort or originality (1)
SIZE: Proportions correct; large and clear to see. Features the correct shape and position.	The ratio between the atoms’ sizes have been researched and visually represented. The molecule is entirely correct in its arrangement. The equation is 3 dimensional.	The ratio between the atoms’ sizes have been researched and visually represented. The molecule is not entirely correct in its arrangement. The equation is 3 dimensional.	The ratio between the atoms’ sizes have been disregarded – the atoms are all represented by the same size. Molecular arrangement is attempted, but somewhat incorrect. Some of the equation is 3 dimensional.	The ratio between the atoms’ have been disregarded – atoms are incorrect sizes. Molecular arrangement is not attempted, and is largely incorrect. Equation is not 3 dimensional.
BALANCED EQUATION	Equation is correctly balanced.	Attempt at balancing the equation is made, but done incorrectly.	Equation is represented, but not balanced.	No representation of equation.
MATERIALS: Original or as instructed; correctly used; environmentally friendly.	No polystyrene or ping-pong balls was used. Materials used are recycled and used in a creative way to represent the atoms comprising the molecule.	No polystyrene or ping-pong balls used. Materials used are recycled, but is not effective, as it is still wet/turning mouldy, indicating poor planning.	Ping-pong balls was used. This is not recycled, but effective and not wet/turning mouldy.	Polystyrene balls used. This is not recycled, and not environmentally friendly.
PRESENTATION			Neat, well-finished.
CLASSIFICATION		Equation is correctly classified.
LABELS: Equation using symbols.	Every component of the model has been labelled correctly, using subscripts in the correct way and the correct symbols and formulae.		Equation using symbols attempted.
WORD EQUATION		Word equation correctly given.	Word equation attempted.