administration student task rubric student work technical quality
Rate of Solvation
Contributed by: Council of Chief State School Officers (CCSSO)
Criterion 1:

Student must state another factor that affects solvation rate besides temperature and must test this factor. The test must include a control. There must be at least two tests that differ by that factor only within the collection of tests in question 1. The tests however do not need to be correct concerning increasing or decreasing solvation rate though this may affect question 2. Examples of factors: stirring, amount of water, amount of sugar, crushing sugar cube, or purity of water.

Criterion 2:

Student must test the effect of temperature on solvation rate. This test must include a control, which means there must be at least two tests that differ only by the temperature in the collection of tests from question 1. The results don't have to indicate that temperature increases solvation rate, or, the student correctly tests an additional factor from criterion 1.

Criterion 3:

Student must state in question 2 a correct reason for temperature increasing solvation rate. The reason must include something about increasing the energy of water or sugar molecules or the speed of the water or sugar molecules or viable explanation for an additional factor from criterion 4 is given. Examples:
1. The water molecules are moving faster.
2. The heat increased the KE of the sugar molecules.

Criterion 4:

Student must state a correct reason for the factor they came up with affecting the solvation rate in question 2. The reason must include whether the rate increased or decreased and why (if solvation rate increase, reaction time decreases and vice versa).


factor effect on rate explanation example
stirring increase keeps water mixed and homogeneous, keeps water going by sugar, keeps concentration around sugar lower
amount of water increase concentration lowered, more water molecules to react with
amount of sugar increase more sugar molecules ro react
crushing sugar cube increase more surface area of sugar, more sugar molecules exposed
concentration of water decrease fewer water molecules free to react


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