Question

starch molecules are too large to pass through the tubing into the beaker. which errors could have caused starch to appear in the beaker despite this fact? check all possible errors.□ not washing the outside of the tubing after filling it with starch□ reusing droppers for different solutions□ adding glucose to the solution in the dialysis tubing□ using a beaker that had not been cleaned thoroughly

Explanation:

1. If the outside of the tubing isn't washed after filling with starch, residual starch on the tubing's outer surface will leach into the beaker, creating a false positive.
2. Reusing droppers between starch and beaker solutions can cross-contaminate, introducing starch directly into the beaker.
3. An uncleaned beaker may have leftover starch from prior use, which would be present in the beaker liquid.
4. Adding glucose (a small molecule that can pass through tubing) does not introduce starch into the beaker, so it is not a relevant error.

Answer:

• not washing the outside of the tubing after filling it with starch
• reusing droppers for different solutions
• using a beaker that had not been cleaned thoroughly