You determine the volume of your plastic bag (simulated human stomach) is 1.05 l. how many grams of nahco3 (s) are required to fill this container given a 70.2% co2 recovery, assuming the other contents in the bag take up a negligible volume compared to the gas. the temperature of the room is 21.5 °c and the atmospheric pressure is 753.5 mmhg.
put it in a beaker. use a smaller beaker filled half way with ice and water and place in the larger one. it should be about an inch or two above the mixture. heat over a bunsen burner and the naphthalene will deposit on the bottom of smaller beaker.
and in this way, nephthalene be separated from the mixture of kbr and sand.
the design of the tube and the chemicals used.
the firework tube is long and narrow one. because the tube is narrow, the mixture of chemicals doesn’t burn so quickly that it will explode.
furthermore, half of the tube is empty, so it behaves as a resonance chamber, like an organ pipe, and interacts with the expanding gases to make the whistling sound.
often, the firework contains alternating layers of oxidizer and potassium benzoate.
when the oxidizer and the potassium benzoate mixture burns, a layer at a time, the sharp explosions cause pressure changes in the gases. a standing sound wave forms in the tube, and this causes the whistle.
as the mixture burns away, the length of the resonating chamber increases. the increasing wavelength of the sound waves creates a descending whistle sound.