Project 6 Presentation

Alex Gonzalez, Chris Miller, and Xiangdong Xiao

Defining the Problem/QuestionHow to utilize the given materials in the lab to create paint solutions that will yield an opaque paint that is cost effective.

Defining the Problem/Question

Importance of Experiment: Creating an opaque paint that is useful for painting so that streaks aren’t created and so the artist doesn’t have to go over the painting surface with multiple coats.

Experimental Design: PigmentFor our paint formulation, we synthesized copper hydroxide by combining copper nitrate (NO3) and sodium hydroxide (NaOH).

Balanced Chemical Equation:

Cu(NO3)2 (aq) + 2NaOH (aq) ----> Cu(OH)2 (s) + 2NaNO3 (aq)

+Pigment was recovered by the use of gravity filtration and letting the pigment dry on the filter paper for a week.

2.0 grams 1.0 gram 1.0 gram

Experimental Design and ProcedureIndependent variable: amount of glycerol in paint

Dependent variable: the opacity of the paint

Controls: The amounts of pigment and vehicle.

Rationale: The purpose for having the solvent as the variable in question was to see if it had an influence towards the opacity of the paint in relations to the controls.

Experimental Design: Trials-Initial Plan: Initially, we had planned to use polyvinyl alcohol (our vehicle) and acetone (our solvent) in addition to the copper hydroxide (the pigment) to create our paint, but ran into problems when the polyvinyl alcohol did not dissolve within the formulation. We were going to change the amount of acetone/trial to see if it affected the drying time and viscosity but were unable to do so.

-Final, Adopted Plan : We tried many combinations of different solvents and vehicles, but finally came back to our initial plan since it was the “best formulation” we could achieve but changed it a bit by adding varying amounts of glycerol (our changing variable/trial as well as new solvent) and used polyvinyl acetate as our vehicle.

Experimental Design: Trials Cont’dCreating paint:

1. Once the pigment was isolated by using gravity filtration (1.6374 g), we took a fraction of the stock pigment and divided it equally into 4 parts (0.163 g)

2. Once the pigment was divided, we added 2 units of polyvinyl acetate to each trial

3. 2 mL of acetone were added to each trial as well4. And lastly the varying amounts of glycerol were added

Visual Representation of Trials

Experimental Design: LastlyExperiment:

1. Put samples of the different paint mixtures on a sheet of paper 2. Allowed the paints to dry3. Ranked the order of opacity using the rubric we created4. Observe correlation between varying amounts of glycerol to opacity

Table: Paint FormulationsTrials

Paint

Pigment

Vehicle Solvent

Copper Hydroxide(g)

Polyvinyl Acetate(units)

Acetone(mL)

Glycerol(mL)

#1 0.163 2 2 2

#2 0.163 2 2 1.5

#3 0.163 2 2 1

#4 0.163 2 2 0.5

Opacity Rubric

Results

4 3

2 1

Graphical Representation of the Results

Sample Calculations- Determining limiting reactant and how pigment we needed: (1.0 g NaOH/1) x

(1 mol NaOH/39.997 g NaOh) x (1 mol Cu(OH)2/ 2 mol NaOH) x (97.561 g Cu(OH)2/1 mol Cu(OH)2)

= 1.21 grams of Cu(OH)2

- Calculating Cost ( Solvent Aspect Example): 7 mL of NaOH/1 x 1L/1000 mL x $36.82/1L

= $0.26

- Cost of most opaque paint: 0.26 + 0.17 + .49 + .09 = $1.01/2.663g

Main Claim

The more glycerol added into the paint mixture, the less opaque the paint was, therefore the least amount of glycerol (0.5mL) led to the creation of the most desired opaque paint.

Discussion of the ResultsThe graphical representation of the results reveals the negative correlation between opacity and the amount of glycerol added to the paint mixture. This trend shows that paint #1, the least amount of glycerol added/ most opaque, was the desired paint out of the four mixtures. Paint #1 requires less coats to get color, thus saving the amount of paint needed to be used. This trend is significant because it was the characteristic that was intended to be discovered by the experiment and leads to the cost efficiency of paints that contain glycerol.

Error AnalysisAccuracy- contamination from the formation of the pigment to the container of the paint mixture itself would affect the accuracy of the results. Also, many measurements leave room for human error in creating the perfect mixture that the experiment needs for accurate results.

Reliability- only one of each paint mixture was tested, the experiment was not repeated which allows for unreliable results. If the experiment was repeated and concluded the same trend then it would prove to be reliable.

Unphysical Results- It is a scientific fact that Polyvinyl alcohol dissolves in water, though it did not appear to dissolve in distilled water or in ultrapure water.

Q&A