Laboratory procedure errors

Question

Explain how the errors in laboratory procedure would affect the calculated percent of sand. (decrease, increase, or remain the same) and why.

1. a bit of mixture got stuck in the film can when you were pouring it into a beaker
2. the mixture was dissolved in too little water; the residue on the filter paper was not washed completely
3. The residue was not dried completely
4. The mixture was dissolved with 30ml of water rather than 20ml of water

Answer 1

Hi Dan,

I do not have the laboratory procedures, but I am going to assume that the sand is the "mixture" in the question.

1. Mixture got "stuck" in the film can when pouring into beaker --> not getting all the mixture so it should go down
2. Mixture dissolved in too little water; "residue left on filter paper" not washed completely --> not getting all the mixture so it should go down
3. Residue not dried completely --> weighing more than just mixture so go up
4. Mixture dissolved with 30 mL instead of 20 mL of water --> amount of mixture in water never changed; only water was changed.

Hope this helps!

-Winn