Melting And Physical Change

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1) First, melting candle wax is a physical change. When heated, the candle wax, which is opaque, white and has a hard, waxy feeling, changed from a solid to a liquid. The hot wax became more of a transparent white and after cooling time, the hot wax changed back into a solid. Changing back into its original state suggests physical change. But, burning candle wax shows evidence of both physical and chemical change. The melting of the wax is an example of physical change, the heat source caused the surrounding wax to melt and drip down the sides of the candle, which then re-hardened after exposure to the air. The flame, is a chemical reaction, which burns wax vapor, which combines with oxygen to produce carbon dioxide and water vapor. Without …show more content…
When adding to the solvent, water, the Nacl spreads throughout. Some of the solute dissolves within the mixture, but the rest sinks to the bottom, the water becomes a transparent, whitish color. When mixing the mixture, the salt will spread evenly throughout and become homogenous. This is physical because nothing changed, the substances just mixed and it is able to be undone. Burning paper is a chemical reaction The lens paper is thin, crinkly, white, and easy to tear. After the paper was lit, it burnt quickly starting at the edges and working its way to the middle. The lens paper did not all burn, but what did turned to ash. The reaction let off a smell and the ash turned to a dark black color. These are two signs of chemical reaction, also the ash created is unable to be reversed back to its original state. Mixing NaCl and AgNO3 is an example of a chemical change. The NaCl, or salt, is small, white, shiny grains, which don’t clump and the AgNO3 is a transparent liquid with a grayish tint, when observing closely there are tiny black flakes floating within. After adding the NaCl to the AgNO3 the mixture turns into a milky color, the salt at the top begins to sink leaving silver chunks on the …show more content…
The first mixture of sodium chloride and water is homogenous the salt equally spreads out when added to the water. After adding sand, the second mixture becomes heterogeneous, the sand sinks to the bottom of the beaker and does not mix among the salt and water.
b. The mixture requires the following materials: 20 mL sand, 100 mL water, 1 gram salt, a glass stirring rod, and a 250 mL beaker. Separating this same mixture requires the following materials: the mixture from the previous step, 2 250 mL beakers, filter paper, 20 mL of extra water, bunsen burner, a sink, and a distillation system. A beaker was set up to hold the mixture, first 100 mL of water was added to the beaker as the base. Following the water, 1 gram of salt was added and stirred until fully mixed by a glass stirring rod. Lastly, 20 mL of sand was added, to the salt water, which sinks to the bottom of the mixture. Then, to re-separate the mixture, the first step was to get another beaker and put a piece of filter paper over the top. The mixture was then poured over the filter paper into the other beaker. This separates the sand from the salt water mixture. 20 mL of extra water was poured over the sand into the beaker to make sure all of the salt remained in the water. The filter paper and sand was then removed from the top of the beaker. The remaining saltwater mixture was inserted into the distillation system, which was also connected to the sink, then the bunsen burner was turned on underneath the mixture.

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