To make ethene from ethanol you have to heat the ethanol soaked in a mineral wool placed in a horizontal; test-tube there is a lump of Aluminium oxide besides the ethanolWhat is the purpose of the Aluminium Oxide?Then the apparatus is changed and now there is a delivery tube connecting the test-tube and a beaker of aq.bromineWhy must the delivery tube be removed from the aq.bromine before the apparatus is allowed to cool?
Need to know the thickness of the foil to calculate volume of the cylinder(if the cylinder is tight rolled)If the cylinder is rolled edge-to-edge, its circumference is 20cm, making a diameter of 20/(pi) 6.37cm or a radius of 3.18cm Volume of a cylinder (pi)r^2L 1400cm^3 - .-- .-
The formula for the volume of a cylinder is pi r^2 h To turn a rectangular sheet of paper into a cylinder, you are turning one side of the rectangle into the circumference of the cylinderThere are two ways in which you could do this Assuming the circumference is 44cm, We have V pi (44/2)/pi 20 22 20 440 square centimeters We can see that if the sheet is rolled the other way, the circumference is 20cm, So we have V pi (20/2)/pi 44 10 44 440 square centimeters, and we can see it is the sameThe volume of the cylinder is 440 cm^2
1) the aluminium oxide is a catalyst (it speeds up the rate of reaction) 2) if the apparatus is allowed to cool with the delivery tube still attached, the air inside the apparatus contracts (it had expanded because of the heat)This contraction creates a vacuum which sucks the water into the delivery tubeThis causes a sudden change of temperature which may crack the glass (it is called suck back)
