Chemical Changes VS Physical Changes Lab Report (Full Name) 3rd period Purpose: To observe the difference between chemical and physical changes. Materials:
- Hot plate
- Water
- Salt
- Evaporating dish
- Candle
- Matches
- Ammonium hydroxide
- Watch glass
- Phenolphthalein
- Paper towel
- Cornstarch
- Iodine
- Cup
- Alka-Seltzer tablet
- Pipet
- Milk
- Vinegar
- Copper II sulfate
- Lead II nitrate
- Goggles were worn.
- Aprons were worn.
- Lab station was cleaned up directly following experiments.
- Hands were washed after experiments.
- No eating or drinking took place in the lab.
- Experiment 1: Put a small amount of water into the evaporating dish.
Dissolve a small amount of salt in the water. Put the evaporating dish on the hot plate and heat slowly (level 5) until all of the water has evaporated. Record your observations on the chart.
- Experiment 2: Take the candle that your group was given and light it.
Observe the candle for a couple of minutes and record your observations on the chart.
- Experiment 3: Place five drops of Ammonium hydroxide to the watch glass. Add two drops of Phenolphthalein. Record your observations on the chart.
- Experiment 4: Get a paper towel and tear it into 20 pieces.
Record your observations on the chart.
- Experiment 5: Put a small amount of cornstarch into a cup. Add a small amount of water to the cornstarch. Add two drops of iodine to the cup.
Record your observations on the chart.
- Experiment 6: Put a little bit on water into a cup. Add half of an alka-seltzer tablet to the water. Record your observations on the chart.
- Experiment 7: Put three pipets full of milk into the watch glass. Add two pipets full of vinegar to the milk. Observe for several minutes. Record your observations on the chart.
- Experiment 8: Put five mL of Copper II sulfate into a cup. Add five mL of lead II nitrate to the cup. Record your observation on the chart.
When the water completely evaporated all of the salt was in clusters throughout the bowl. Physical Change|2 The candle was lit and the wick turned black to indicate it was burning. The wax surrounding the wick began to melt and form a puddle. After burning for a few minutes the puddle grew.
| Chemical Change (burning wick)Physical Change (melting wax)|3 The ammonium hydroxide was clear when placed in the watch glass. Originally, when the Phenolphthalein was added it turned a murky white color. Ms. Steinhauser explained how that was not supposed to happen so the ammonium hydroxide was replaced and when Phenolphthalein was added to the new ammonium hydroxide it changed to a purple-ish color. Chemical Change|4 When the paper was ripped nothing changed except how many pieces of paper there were and the surface area of each piece.
A noise was made but nothing else happened. | Physical Change|5 When iodine was added to the cornstarch it turned to a blue-ish black color. This happened to signify that the cornstarch is, in fact, a starch. | Chemical Change|6 The alka-seltzer tablet was added to the water and began to dissolve. It bubbled and the surrounding area turned white from the alka-seltzer dissolving.
The bubbles indicated the chemical change occurring in the alka-seltzer. Chemical Change|7 The vinegar, when added to the milk, separated with the milk because milk is a base and vinegar is an acid. The milk was curdled because of the vinegar being added to it. Physical Change8 When lead II nitrate was added to the copper II sulfate it turned from blue to white and began to fizz. It formed a precipitate which indicates a chemical change. | Chemical Change| Data Analysis: 1.
List all of the different signs that you observed that indicated that a chemical change had occurred.
- In experiment 2, the burning wick turned from white to black. This signifies a chemical change because it was a change in color.
- In experiment 3, the ammonium hydroxide changed from clear to purple when phenolphthalein was added. This signifies a chemical change because the color changed.
- In experiment 5, the iodine changed from black to blue to indicant a starch.
This signifies a chemical change because of the color change.
- In experiment 6, the alka-seltzer, when added to water, produced bubble in water which means it was emitting gas. This signifies a chemical change because gas was produced.
- In experiment 8, the lead II nitrate and copper II sulfate mixture fizzed and formed a precipitate.
2. Which experiments were examples of chemical changes? * Experiments 2, 3, 5, 6, and 8 were examples of chemical changes. 3. Which experiments were examples of physical changes? * Experiments 1, 2, 4, and 7 were examples of physical changes.
4. How did you know a physical change had occurred? * The Composition of the matter did not change although a factor changed how the matter looked.Conclusion: The lab we were asked to perform focused on the physical and chemical changes that occur with different types of experiments.A physical change is a change that does not alter the substance’s identity.
A chemical change is a change that alters the identity of a substance. A chemical change can be identified by five things: change in mass, formation of a precipitate, release of heat and/or light, color change, or giving off gas. Physical changes occurred in four out of the eight experiments completed in this lab. The first was experiment one, the salt and water.
The salt was added to water but when the water evaporated the salt remained. The water changed to the vapor form of water and the salt did not change. The second was experiment two, the candle.When the candle was lit the heat given off from the fire melted the wax beneath it. Melting is a physical change because the liquid wax is still wax, its usual form is just a solid.
Experiment four dealt with ripping paper. This was a physical change because, although the paper was being ripped apart, it was (and still is) paper. The smaller pieces did not change the mass or any other factor of it except the surface area of each piece. Experiment seven dealt with vinegar being added to milk. The vinegar did not change but the milk was curdled by the vinegar.
Although the milk was curdled, the milk remained milk.The composition stayed the same. Each of these experiments showed no change in a substance so as it changed to another substance. Chemical changes occurred in five out of the eight experiments completed in this lab.
Although the main focus of experiment two was the melting wax, the wick experienced a chemical change due to the fire burning it and it changing from white to black. In experiment three, ammonium hydroxide changed from clear to purple when phenolphthalein was added to it. Experiment five and experiment eight had a similar effect when the iodine turned blue and the copper II sulfate turned white.A chemical change can be seen through the color change of a substance.
Experiment six dealt with adding an alka-seltzer tablet to water. When the alka-seltzer was added it fizzed and produced bubbles because it began to dissolve. Gas was produced due to the breakdown of the alka-seltzer. The production of gas signifies a chemical change. Experiment eight that dealt with the copper II sulfate and lead II nitrate, changed colors as well as formed a precipitate.
The formation of a precipitate due to the combination of chemicals signifies a chemical change.The Changes occurring in each experiment prove the change in a substance due to the breakdown or alteration of a substance by another substance. Depending on the type of force altering a substance, a physical change may occur as opposed to a chemical change (or vice versa). The five key indications of a chemical change prove true through these experiments as I observed a substance change. No substance change occurred in a physical change although something did happen to it; it remained the same substance.
Application to everyday life: Cooking includes many different applications of chemical and physical changes.These changes, however, may not be possible if it weren’t for the tools in which help the changes occur. The physical change of preparing a salad (heterogeneous mixture) occurs in a bowl which, if made of clay, would have been created by a physical change by shaping the clay and letting it harden. If the bowl was made of glass the glass would have undergone a physical change including extreme temperatures and the formation of the glass bowl from a hot liquid to a shaped and cooled solid. The salad itself is created by chopping up vegetables, which is a physical change, and adding them together in a bowl of choice.
Meat placed on a hot stove cooks because of the transfer of heat energy from the stove to the meat, which is a physical change because the meat remains meat. The stove, on the off-chance it may be a gas stove, burns gas to produce heat. This process is a chemical change; burning gas changes the composition of the gas. The creation of heat also signifies the chemical change.
The meat on the stove, however, if burned, transforms from meat to char to ash. This is a chemical change because the meat is transformed to ash; the color and mass change. Ice cubes are made from water freezing.This is a physical change because ice is still a form of water.
The ice cube trays, typically made of plastic, undergo physical changes as well. Plastic is created (or melted down when remade from recyclables) and melted to be molded. The melting and molding are forms of physical changes because the plastic is still plastic, just in liquid form and in a different, molded form. The ice created will remain ice at 0 degrees Celsius or 32 degrees Fahrenheit.
Another physical change will occur if the ice is taken from the freezing temperature into a warmer area. The ice will melt and form back to water.
