Lab Chemical and Physical Properties

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

!
!

Physical and Chemical Properties!

Purpose/Hypothesis:!
• The purpose of this experiment is to investigate the chemical and physical properties of pure chemical substances. A property of a substance is some distinguishing characteristic. Some of the most common physical properties are color, odor, hardness, density, melting point, boiling point, and solubility in various solvents. For all of these properties, no chemical change takes place.
Chemical properties describe the tendencies of a substance to undergo chemical change. For example, copper gets heated in a flame, the surface of the metal turns black. Cooling will not restore it to its natural color. At high temperatures copper reacts with oxygen to produce a new compound, copper dioxide. A chemical reaction takes place on the metals surface. Each new product formed from a chemical change has its own characteristics. So, my hypothesis is that we will see both chemical and physical changes in all of these substances as the experiment happens. Some will have more chemical changes than others, some will have more physical changes. I think they will all have at least some chemical and physical changes. !

!

Procedure: !
1. Half-fill one well of a 24 - well plate with 6 M HCl and half-fill a second well of the 24-well plate with 6 M NaOH. Suck up the chemicals into their labeled pipets for later use. !
2. Perform the following steps on each of substances being tested. Complete all the tests of one substance and record your observations before going o to the next. !
3. Place 4 small test tubes into wells of the 24-well plate. !
4. Place small amounts of the substance to be tested in each of the four micro test tubes. !
First Test Tube: !
1. Examine and record the color and odor. !
2. Light the burner fuel. Grasp the test tube with the holder and heat the sample by moving the substance above the flame slowly. Observe the effect of heat on the substance. Not the evolution of any gases. !
3. Allow the test tube to cool before putting it back in the well. !
Second Test Tube: !
1. Add enough cold water to fill 1/4 of the test tube. Stir wight he glass stirring rod. Observe the solubility of the substance in cold water. !
2. Grasp the test tube and heat the sample by moving it over the flame with the water in it.
Gently heat the water just to boiling. Observe the solubility in hot water. !
3. Tear off about half a centimeter of both red and blue litmus paper/ !
4. Allow the solution to cool, then using the glass stirring rod, transfer a drop of the solution into both pieces of litmus paper. Record the results and clean the stirring rod. !

!
!
!

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

!

Third Test Tube: !
1. Add a few pipet drops of HCl (hydrochloric acid) to the sample and stir. Use the test tube holder because some reactions are exothermic. Record any apparent reaction or solubility and clean the stirring rod. !
Fourth Test Tube: !
1. Add a few drops of NaOh (sodium hydroxide) to the sample., Stir and record any reaction or solubility. Clean the stirring rod. !
5. Thoroughly clean and ry all 4 test tubes. Repeat steps 2 through 6 with all other substances. !

!
Data/Observations: !
!
!

Solubilit y Or

Reaction

Substanc Color e Name

Odor

Effect of
Heat

Cold
H2O

Hot H2O

Litmus
Test

Dilute
HCl

Dilute
NaOH

Mg

Silver
Color.

None

Slightly
Melted
the substanc e, but that is it.
No
gasses were given off.

No
Solubility
in Cold
Water.

Very little
Solubility
in hot water. No change in
Color for either the red or blue litmus paper. Started to bubble and continued to bubble. It became completel y soluble with the
HCl and it became one substanc
e.

When the
NaOH hit the Mg, nothing happene
d. It didn’t solute and no reaction happene d at all.

Cu

Metallic,
Gold,
Bronze
Color.

Very little odor, smells like regular
Copper.!

The
Heat
made the copper become a much darker color, but that is it.
No
gasses were given off.

No
Solubility
in Cold
Water.

No
Solubility
in hot water, the copper turned slightly darker again. No change in color for either the red or blue litmus paper. Nothing happene d when the Acid hit the copper. It also had no solubility when it his the acid. Nothing happene d when the NaOH hit the copper. It also had no solubility when it his the
NaOH.

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

Zn

Silver
Color.

Has no odor. Solubilit y Or

Reaction

Melted to a liquid form of
Zinc. It turned slightly darker than at first. No gasses were given off.

No
Change
of
Solubility
in Cold water. The Zinc slightly melted and changed shape and became slightly soluble the hot water. The red
Litmus
Paper had 0 color change, and the blue litmus paper turned slightly more violet colored.

When the
Acid hit the Zinc the acid started bubbling.
It gave of a gray a gas while this was happenin g and the zinc turned into a blackish gray color instead of silver like in the beginning .

Nothing happene d when the Zinc hit the
NaOH. It didn’t become soluble and no reaction happene d and no gas was given off.

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

MgO

White,
Powdery
Color.

Has a slight odor of baby powder. It has more smell than the last three we tested.

Solubilit y Or

Reaction

The powder became a very slightly darker color and gave of a gas.
The gad smelled slightly like burning rubber. The powder was very soluble in cold water.
When I mixed the cold water and powder together it became one phase.
The color of the liquid was a milky white.

When the water was heated up, the color of the liquid became slightly less milky white. It boiled much faster than the previous three would have.

When we put the milky white liquid of water and MgO on the red litmus paper, it turned into a blue/ purple color. When we put it on the blue litmus paper, it became a more violet color as well. When the
Powder
hit the acid, it became yellow.
Then
when I mixed them it became a yellow liquid that bubbled and made a very small amount of gas. It also heated up as well. When the
NaOH hit the MgO nothing really happene d. It changed to a slight brown color but nothing was produced from it.
The
powder became more pasty because of the combinati on of a liquid and solid. Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

CuCO3

Green,
Powdery
Color.

No odor

Solubilit y Or

Reaction

The powder turned black when it was heated up. It have of a gas that didn’t have much of an odor.

The
Powder
was extremely soluble in water. It didn’t even need to be mixed to become a homogen ous mixture with the water. It became a greenish white liquid when they combined
. After a minute, the
Powder
sank to the bottom of the liquid.

Nothing really happene d when the liquid was heated up. It started boiling and the powder on the bottom started to rise up.

Neither color of litmus paper changed color very much when it hit the liquid. I think this is because the powder and the water slightly separate d.

When the substanc e hit the acid, it started to bubble and produce a slight gas. The color of the green powder became slightly darker and solutes with the acid. It had a reaction and created a gas. When the substanc e hit the
NaOh,
the powder started to bubble, but didn’t create a visible gas. The powder turned into a blue color and solutes with the liquid. I think it created a gas, just not a visible gas or a very little quantity of it.

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

Cu(NO3)
2

Blue,
Crystal
Structure
Color

Very little odor, doesn’t smell like much. Solubilit y Or

Reaction

When the substanc e got heated it became a much darker blue and began to melt. It didn’t really give a gas, it just became more liquify than it was it first. When the substanc e hit the water it solutes pretty easily. I had to use the stirring rod to mix it into one phase just barely. It was a clear blue color that looked similar to water. When this was boiled it didn’t do much. It started to bubble and give of a little gas, but because it was already soluble it didn’t do much different.

When the liquid hit the litmus paper, the red one didn’t change any color at all.
But,
when the liquid hit the blue it turned into a bright reddish purple color. It became darker red after a minute.

When the
Acid hit the substanc e nothing really happene d except of a color change. It changed from blue to green.
It didn’t bubble or produce a gas, but it did become soluble with one another. When the substanc e hit the
HaOh,
nothing happene d. It became soluble with the
NaOh,
but that is it. No reaction, no color change or anything. Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

NaCl

White,
Crystal
Color

Not much smell, has a very similar scent to salt. !

Solubilit y Or

Reaction

When the NaCl was heated it became black very quickly. I didn’t see it bubble or give off a gas, it just became black and burned very fast.

When the
NaCl was mixed with cold water, it didn’t solute into one mixture. The NaCl was on the bottom while the water was on the top.

When the
NaCl and cold water was heated up and then mixed again, it solutes much better. It became one phase that looked just like regular clear water. So, even though in cold water it didn’t mix, it did in hot water. When the
Liquid
was put on both colors of litmus paper, neither one of them changed colors. They both remained the same color and nothing really happene d.

When the substanc e combined with the acid nothing happene d except that the acid and the substanc e combined into a liquid. No reaction occurred and no gas was created, it just mixed together to create a liquid.

When the
Substanc
e hit the
NaOH,
nothing happene d. They became one solute mixture, but no bubbling took place and no reaction happene d either.

• I recorded all of my observations in the graph above and I feel like I did a good job of gathering information and collecting data. I learned about the physical and chemical changes of the different substances used in this experiment. !

!

Results/Analysis: !
• The result of this experiment was that I was able to find different chemical and physical properties of all of the different substances being used. There so was not much data in this experiment except for my observations, but I feel like I did a good job of completing the experiment thoroughly and gathered useful information about all of the chemical compounds. I hd no measurements in this experiment, so I cannot explain the theoretical measurements or the real measurements of this experiment. I did not come across many errors throughout this experiment. The only one I had is I used slightly less HCl on the NaCl because I was almost out and only had a little left. I don’t think this had a major impact on the reaction because either way I don’t think it would have reacted. One other thing that happened was a melted the
Zinc and it got somewhat stuck to the test tube, so it was slightly difficult to get out, but

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014

!

besides those to minor errors which didn’t have much effect at all, I think the experiment went very smoothly. !

Questions: !
1. Did you observe any chemical changes in this experiment? !
• I observed many chemical changes during this experiment. One of the most prominent examples was when the Zinc combined with the hydrochloric acid to create an extra gas. A few others were when MgO and the CuCO3 hit the HCl it also had a reaction and created an external gas. !
2. What evidence did you use to decide that something was a chemical change? Give at least two examples of chemical changes you observed. !
• The evidence was the production of a new substance like a gas. The two examples I have are when the Zinc combined with the HCl and when the CuCO3 combined with the HCl. Both times, they started to bubble and create new gasses when the reacted to one another. !
3. Classify the following properties of sodium metal as physical or chemical: !
!
• Silver metallic color: Physical !
!
• Turns gray in air: Chemical !
!
• Melts at 98 degrees Celsius: Physical !
!
• Reacts explosively with chlorine gas: Chemical !
4. Classify the following changes as physical or chemical:!
!
• Water freezes at 0 degrees Celsius: Physical !
!
• Baking soda when combined with vinegar produces bubbles: Chemical !
!
• Mothballs gradually disappear at room temperature: Physical !
!
• Ice cubes in a freezer get smaller with time: Physical !
!
• Baking soda loses mass as it is heated: Chemical !
!
• Tarnishing of silver: Chemical !
5. How would you show that dissolving table salt is a physical change. !
• You can show that dissolving table salt is a physical change because you physical changes can always be changed back or reversed. So, you could dissolve the table salt in water, and then let all of the water evaporate and get the salt back. This shows that it is a physical change. Another way to know is jus by knowing solubility is a physical change not chemical, so with that knowledge you would know that dissolving table salt is a physical and not chemical change. !

!

Conclusion: !
!
Overall, I think my experiment went very well. I was able to test all of the properties of all of the different substances and determine whether or not the change was chemical or physical. I learned that things like melting, boiling, and solubility are all physical changes, I also learned that when an extra product is made during a reaction, then the change is a chemical change. If I were to do this over again, I think I wouldn’t change much. I would probably save some the of
HCl (Hydrochloric Acid), so I could evenly distribute it instead of using a couple drops on the last substance. That is the only thing I would redo if I were to do that lab over again. Some interesting observations I had was that most things had chemical reactions when the HCl. Not many of them were as reactive to the NaOh. The most successful was when the Zinc mixed with the HCl because you could really see it bubbling, and you could see a definite gas being produced by the reaction. !

Jonah Bluh!
Honor’s Chemistry !
Experiment Number 6 !
November 28, 2014
!
I think that is lab was very beneficial to me. I was able to apply what I learned from the textbook to an actual situation that needed it. I already knew about chemical and physical changes from previous science classes, but it is always good to refresh you memory. I know completely understand the difference between the two, and I thought it was really good practice to have. The concepts in this lab were very easy to grasp and I thought I did a good job of learning and understanding them. I think this was an easy lab that just took a little while longer, but had many benefits. I learned the difference between the two properties and got to see them take place in different chemical compounds. So, I think it was very beneficial and I am glad I participated in this lab.!
!
The one very minor error had during this experiment was that when I was melting the zinc, some of it got stuck to the bottom of a test tube and it took me a minute to scrape it up.
That was the only error I had and it didn’t really have an effect on the experiment. Besides that, I think my lab went excellent and I learned a lot. I am really glad I participated in it, and there were almost no bumps. I think this lab was done with precision and care and I am proud of the results I got from this experiment.