Name______Per.______Date______

Lab Procedures: MEASURING SOLIDS

OBJECTIVE:

To measure, transfer and crush a solid successfully.

MATERIALS:

Electronic Balance: used to measure the mass of solids

Scoopula: used to transfer solids

Mortar and Pestle: used to crush solids into a fine powder

Stirring rod with a Rubber Policeman: used to help transfer all of the solid by scraping the sides of a container.

Weighing paper: Used to hold the solid on the balance. Chemicals should never be put directly on the balance pan.

Sodium Chloride: also known as table salt. The solid used in this activity.

SAFETY: Students should wear goggles throughout the lab. Do not directly touch any chemicals. NEVER place chemicals or hot objects directly on the pan; use weighing paper. Clean up any solid spills with a dustpan and brush. NEVER push on the balance pan or overload the balance.

RECORDING OBSERVATIONS:

-  Use your senses (seeing, hearing, smelling). Describe what you notice using your senses. Be specific!

-  Label parts of the equipment.

-  Answers all questions.

PROCEDURE:

1.  When a balance is required for determining mass, you will use an electronic balance. Our electronic balances read to 0.01 g.

Question: In the metric system, which prefix stands for 1/100 or 0.01?

2.  Turn on the balance. Look for the “g”. If not in grams, use the mode button until the “g” appears.

Question: What unit does the “g” represent?

Question: Why should you never place hot objects or chemicals directly onto the balance pan? What could happen to the balance? (Hint: Look at what the balance pan is made of).

3.  After the balance is on the correct unit, place a piece of weighing paper on the balance. Hit the zero button to take the reading back to zero.

4.  Add approximately one gram of sodium chloride to the weighing paper.

Question: Record the actual amount of sodium chloride obtained as seen on the balance (include the number AND the unit):

5.  Transfer the sodium chloride from the weighing paper to the mortar and pestle. Grind the salt into a powder using a rotating motion (not a pounding – this could create hazardous dust if it were a toxic substance).

6.  Once the salt is a powder, transfer the powder into the waste container using the stirring rod with the rubber policeman.

7.  CLEAN-UP:

-  throw away weighing paper into trash can

-  rinse and dry mortar and pestle and the stirring rod with the rubber policeman