Chemical change,5. Physical change, 6. Chemical change, 7. Physical change, 8. Chemical change, 9. Physical change, Chemical change, Physical change. P re K Education. Canvas Logins Find an Institution. Resources and services for Utah Higher Education faculty and students such as Canvas and collegEmedia. Content and resources for career literacy and preparation. Career Ed News. Our goal is to educate, engage, and enrich the lives of Utah residents through broadcast programs and services.
On-Demand Support , opt. Tech Services I'm Freezing! Disappearing Act! This is Gross! Watch Me Change! Chemical Reactions This is the same substance the candle needs to burn in a chemical change that we call combustion.
We are not aware of oxygen in the air because it is an odorless and colorless gas, and at the temperature of a burning candle, both the CO2 and the H2O are also gases that are invisible to us.
We can see evidence of chemical change, however, if we restrict the amount of oxygen that is allowed to react with the wax. Relight the candle and lower the bottom of a small beaker or a clear watch glass into the flame so that the flame touches the surface of the glass. Hold it there for a moment where it restricts some of the air flow to the flame and then remove it. Finally, let us consider the physical phase of the wax as it reacts with the oxygen to produce carbon dioxide and water.
Prepare to observe carefully! Blow out the candle and very quickly bring a match close to the wick. Try to notice exactly where the lit wooden splint is with respect to the wick when the candle reignites. Do this several times to see if you observe something interesting. Note any evidence you have observed that helps to determine the physical phase of the wax when it reacts with oxygen. If you do not respond, everything you entered on this page will be lost and you will have to login again.
Skip Navigation. Lab Investigation. Teacher's Overview Summary In this investigation, students are challenged to make careful observations about a burning candle to discover the chemical and physical changes that make it work.
Objective Students will desribe their observations about a burning candle to discover the chemical and physical changes that make it work. Safety Be sure to wear safety goggles while making close observations, tie your hair back if you have long hair, and always be aware of where the flame is with respect to your clothing—do not lean over the flame.
Burning candles are open flames that can cause burns. Liquid wax is hot and can cause burns to the skin. Lab Tips Tea candles can be purchased in large quantities, as can tapered candles from hardware stores.
Student Investigation. Preparing to Investigate. Gathering Evidence. Record your obervations. Qualitative observations Quantitative observations 1. Record your observations. Label the following regions of the candle in your drawing: solid wax liquid wax region of wick without flame region of wick with flame region of the wick that glows Now distinguish as many different aspects of the flame itself and label them in the drawing.
Interpreting Evidence. Part One. Waxes from plants and animals have different structures. Here is a molecule similar to wax— a material that is normally a major component of the candle wax. Describe this evidence as specifically as possible. Did you find evidence for the change from the liquid wax phase to the gaseous wax phase?
A physical candle is composed of wax surrounding a wick. Describe the wicking process in the burning candle, and be sure your description includes the physical state of the wax and the wick. One good example of a chemical change is burning a candle. The act of burning paper actually results in the formation of new chemicals carbon dioxide and water, to be exact from the burning of the wax.
Another example of a chemical change is what occurs when natural gas is burned in your furnace. In this case, not only has the appearance changed, but the structure of the molecules has also changed. The new substances do not have the same chemical properties as the original ones. Therefore, this is a chemical change. We can't actually see molecules breaking and forming bonds, although that's what defines chemical changes. We have to make other observations to indicate that a chemical change has happened.
Some of the evidence for chemical change will involve the energy changes that occur in chemical changes, but some evidence involves the fact that new substances with different properties are formed in a chemical change.
Label each of the following changes as a physical or chemical change. Give evidence to support your answer. Homogeneous mixtures solutions can be separated into their component substances by physical processes that rely on differences in some physical property, such as differences in their boiling points. Two of these separation methods are distillation and crystallization. Distillation makes use of differences in volatility, a measure of how easily a substance is converted to a gas at a given temperature.
A simple distillation apparatus for separating a mixture of substances, at least one of which is a liquid. The most volatile component boils first and is condensed back to a liquid in the water-cooled condenser, from which it flows into the receiving flask.
If a solution of salt and water is distilled, for example, the more volatile component, pure water, collects in the receiving flask, while the salt remains in the distillation flask. Mixtures of two or more liquids with different boiling points can be separated with a more complex distillation apparatus.
One example is the refining of crude petroleum into a range of useful products: aviation fuel, gasoline, kerosene, diesel fuel, and lubricating oil in the approximate order of decreasing volatility. Another example is the distillation of alcoholic spirits such as brandy or whiskey. This relatively simple procedure caused more than a few headaches for federal authorities in the s during the era of Prohibition, when illegal stills proliferated in remote regions of the United States.
Filtration is any of various mechanical, physical or biological operations that separate solids from fluids liquids or gases by adding a medium through which only the fluid can pass. The fluid that passes through is called the filtrate.
There are many different methods of filtration; all aim to attain the separation of substances. Separation is achieved by some form of interaction between the substance or objects to be removed and the filter. The substance that is to pass through the filter must be a fluid, i. Methods of filtration vary depending on the location of the targeted material, i.
Learning Objectives Label a change as chemical or physical.
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