Item SC069007: When a chemical reaction occurs, the characteristic properties of the products are different than the characteristic properties of the reactants. (This item used a table to show the properties of the substances.)

A student determines the density, solubility, and boiling point of two liquids, Liquid 1 and Liquid 2. Then he stirs the two liquids together and heats them. After stirring and heating the liquids, two different liquids form, Liquid 3 and Liquid 4. Then the student determines the density, solubility, and boiling point of Liquids 3 and 4. He concludes that a chemical reaction occurred. Here are his results:

  Density (g/mL) Soluble in Water Boiling Point (°C)
 
Before stirring and heating Liquid 1 0.96 Yes 164
Liquid 2 0.81 Yes 118
 
After stirring and heating Liquid 3 0.87 Yes 166
Liquid 4 1.00 Yes 100

How does the student know that a chemical reaction has occurred?

  1. The student knows that a chemical reaction has occurred because
    Liquid 3 has different properties than Liquid 4.
  2. The student knows that a chemical reaction has occurred because
    Liquid 1 has different properties than Liquid 2.
  3. The student knows that a chemical reaction has occurred because
    Liquids 3 and 4 have different properties than Liquids 1 and 2.
  4. The student knows that a chemical reaction has occurred because
    a chemical reaction always occurs when two liquids are mixed together.

Distribution of Responses

Chart showing distrubtion of responses for Item SC069007

Percent of students responding correctly

Overall61%
Grades 6–855%
Grades 9–1265%
Male62%
Female60%
Primary Language is English62%
Primary Language is not English51%

View data table

(Modified from IQWST)