Name Period Date

Partners

It is often necessary to separate mixtures of two or more substances. There are many different ways of accomplishing this process. In this experiment, a mixture of sand, salt, and iron shavings (filings) will be separated in order to determine the percent composition of the mixture. At the end of the separation, the individual components should add up to the original mass of the mixture.

ALL DATA SHOULD BE RECORDED IN YOUR DATA TABLE!

ALL PARTNERS MUST PARTICIPATE!

SAFETY: Wear safety goggles, closed-toed shoes, and a lab apron at all times.

DAY 1 PROCEDURE

  1. Get avial of sand, salt, and iron filings and obtain its mass.
  2. Pour the mixture out onto a clean paper towel. Get the mass of the empty vial.
  3. Weigh a piece of filter paper and record its mass.
  4. Remove the iron filings by using a bar magnet. NOTE: the magnet must be wrapped completely using plastic wrap before removing the iron. Place filings on thepre-weighed piece of filter paper and record the mass of the iron and filter paper.
  5. Get another piece of filter paper and write your name in pencil on an outside edge. Fold the filter paper as shown on the diagram below (with your name visible), and record the mass of the empty filter paper. Place the filter paper in the funnel, wetting it slightly to help it stay.
  1. Place the remaining sand/salt mixture in a small beaker. Add roughly 20mL of water to the mixture in the beaker, and stir with a stirring rod until all of the salt has dissolved.
  2. Obtain a clean, dry Dixie cup. PUT YOUR INITIALS ON THE CUP. Use the cup to catch the filtrate. You may need a second cup for all of the filtrate; if so, label it also. Filter the mixture through the funnel containing the filter paper as shown in the diagram below.
  1. Use your wash bottle to wash any sand in your small beaker into the filter paper. When you are done, carefully remove the filter paper and place it on a tray to dry. Cover your filtrate cup(s) with a paper towel and leave it on the counter for further work tomorrow.
  2. Clean your glassware and your lab area and put all of your equipment away.

DATA TABLE DAY 1

MeasurementValue

Mass of full vial g

Mass of empty vial g

Calculated mass of mixture g

Mass of empty filter paper g

Mass of iron on filter paper g

Calculated mass of iron filings g

Mass of second filter paper g

Questions

1. Define (a) heterogeneous mixture

(b) homogeneous mixture

(c) pure substance.

2. Give an example, fromthis experiment, of (a), (b), and (c) above.

3. What physical property/properties of iron allowed you to separate it from the rest of the mixture?

4. What physical property/properties of sand allowed you to separate it from the rest of the mixture?

5. What exactly is in your Dixie cup (the filtrate) at the end of today’s lab?

DCG-2014

Name Period Date

Partners

In today’s lab, you will separate the salt from the water and determine how much sand you collected.

ALL DATA SHOULD BE RECORDED IN YOUR DATA TABLE!

ALL PARTNERS MUST PARTICIPATE!

SAFETY: Wear safety goggles, closed-toed shoes, and a lab apron at all times.

DAY 2 PROCEDURE

  1. Weigh a clean, dry 250-ml beaker.
  2. Weigh a clean, dry watch glass.
  3. Transfer the filtrate from your Dixie cup(s) into your beaker. Rinse the Dixie cup with distilled water in order to transfer everything into your beaker.
  4. Place your beaker that contains the salt water onto a wire gauze on a ring stand. Put the watch glass over the beaker to prevent spattering. Evaporate the water by boiling gently. When the beaker is dry and completely cool to the touch, obtain the mass of the beaker and watch glass and solid residue.
  1. Find your dry filter paper with sand and obtain its mass.
  2. Throw away the filter paper and sand. Clean your lab area and all glassware. Put all equipment away.

DATA TABLE DAY 2

MeasurementValue

Mass of clean 250-mL beaker g

Mass of clean watch glass g

Mass of beaker and watch glass with salt g

Calcuated mass of salt g

Mass of sand and filter paper g

Mass of filter paper from yesterday g

Calculated mass of sand g

Calculations

Show your work for all calculations!

  1. Calculate the total mass of the recovered mixture: mass of iron collected + mass of sand collected + mass of salt collected
  1. Calculate the % composition of iron in the mixture: (mass iron/mass of mixture) x 100
  1. Calculate the % composition of sand in the mixture: (mass sand/mass of mixture) x 100
  1. Calculate the % composition of salt in the mixture: (mass salt/mass of mixture) x 100
  1. Calculate the % error:

Questions

1. Were the changes in the materials in this lab physical changes or chemical changes? How do you know?

2. Did the sum of the masses of the recovered iron, sand, and salt equal the mass of the original mixture? Why or why not?

3. While on a camping trip, all of the salt you have is accidentally spilled onto some sand. How do you get the salt back (you don’t camp with filter paper)?

8. On the same camping trip, you spill again! How could you separate a mixture of charcoal, sugar, and sand?

DCG-2014