Ferrous Sulfate - Amount Needed

[deleted-89863]

Hi!

I have two questions:

1. I want to substitute ferrous sulfate in place of copper sulfate pentahydrate as a mordant for my experiment. The procedure normally calls for dissolving "1.5 g copper sulfate pentahydrate in 75 mL distilled water". How much ferrous sulfate would I need to add to 75 mL?

2. Can the ferrous sulfate solution be safely disposed of in a sink?

Thanks!

[norman40]

Hi proscience,

One way to prepare your substitute solution is to make the number of moles of iron the same as the number of moles of copper in the original solution. The calculations are as follows.

The number of moles of copper in 1.5 g of copper sulfate pentahydrate is
(1.5 g)/(249.7 g/mole) = 0.006007 moles.

The weight of ferrous sulfate heptahydrate needed for the same number of moles of iron is
(0.006007 moles)*(278.0 g/mole) = 1.67 g.

I'm glad you asked about safe disposal of chemicals. I think that every chemistry project should include some research on how to safely work with and dispose of the chemicals involved. One place to start is a material safety data sheet (MSDS).

http://avogadro.chem.iastate.edu/MSDS/FeSO4.htm

That said, I don't think you should dispose of your ferrous sulfate solution in a sink. My suggestion is to put your solution in a closed plastic bottle. Label the bottle “ferrous sulfate/water solution” and include the weight of ferrous sulfate on the label. You can take the solution to the waste chemical disposal facility in your community.

I hope this helps and good luck with your project. Please post again if you have more questions.

A. Norman

[deleted-89863]

Dear A. Norman,

Thank you for the information! Is an N95 face mask okay to use when I handle the ferrous sulfate? Or do I need a different kind of mask? It is recommended to use a mask to prevent breathing in the iron dust.

I am doing this experiment at home, not in a lab. My project is based on textile chemistry. I was going to use the ferrous sulfate outside for ventilation and a face mask and gloves to prevent inhaling and absorbing the iron.

Much of my data will be qualitative (observation of colors). Since I do not have access to instrumentation, I have to use what is available to me at home to quantify my results. I was going to use an html color picker app to record HSB values based on photos of my fabric samples.

I am testing colorfastness by exposing my samples to sunlight over a period of 4 - 6 weeks. But that is qualitative data, unless I measure HSB values again after fabrics are exposed to light. Science Buddies suggest making a bar chart with the average HSB values and the type of fiber used.

Can you suggest other ways to collect quantitative data? Or what other types of graphs I could use? My dependent variables are the dye materials (4 of them), and 2 types of animal fibers. My independent variable is the mordant ( 2 types of mordants: alum and ferrous sulfate).

Thanks!

[deleted-89863]

Oh! I forgot to tell you that I am making my own plant dyes.

[norman40]

Hello proscience,

I think the N95 type of dust mask will be OK for your purposes. You shouldn't encounter much dust given the small amounts of materials you are working with.

I like your idea of using a color picker app to quantify color changes due to sunlight exposure. One suggestion for the fabric sample photos is to use the same lighting, camera position and fabric position for all of your photos. You might consider putting together a “photo station” that you leave in place for the duration of your project.

Bar graphs are great for comparing quantitative data from different categories. For example, the hue results for fabrics treated with your 4 different dye materials. You might try an x-y plot to show how hue changes with sunlight exposure. In this case you'd plot exposure time on the x axis and hue on the y axis. You could have one of these graphs for each of your dye types, fiber types and mordants.

You mentioned dependent and independent variables. Independent variables are things that you change in your experiment to get a response in a dependent variable. Based on what you've described about your project, I think your independent variables are dye material, animal fiber and mordant. Your dependent variable is colorfastness (or change in color due to sunlight exposure).

I hope this helps. Please post again if you have more questions.

A. Norman

[deleted-89863]

Dear A. Norman,

Thank you very much for your explanation. I really appreciate your expertise in helping me with my project.