Wilhelm Conrad Roentgen was a German scientist who discovered x-rays through the use of Crookes tube, a tube he used in studying cathode rays that emitted new kinds of invisible ray that was capable of penetrating through a black paper.
After hearing such discovery, Henri Becquerel, a French scientist had also took interest in the connection between the phosphoresence he had already been investigating and the newly discovered rays. He thought that the phosphoresence uranium salts he had been observing and studying might absorb sunlight and emit it as x-rays.
To test such idea which was disproved later on, Becquerel wrapped photographic plates in black paper so that sunlight could not reach them. He then placed the crystals of uranium on top of the wrapped plates and put the whole set up outside, exposed under the sun.
When he developed the plates, he saw an outline of the uranium crystals. He also placed other objects such as coins or cut out metals between the crystals and the photographic film/plate. It also turned out that he could also produced outlines of those shapes.
Answer:
1.32 moles.
Explanation:
From the question given above, the following data were obtained:
Density of Al = 2.70 g/cm³
Volume of Al = 13.2 cm³
Number of mole of Al =.?
Next, we shall determine the mass of Al.
This can be obtained as follow:
Density of Al = 2.70 g/cm³
Volume of Al = 13.2 cm³
Mass of Al =?
Density = mass / volume
2.7 = mass of Al / 13.2
Cross multiply
Mass of Al = 2.7 × 13.2
Mass of Al = 35.64 g
Finally, we shall determine the number of mole of Al. This can be obtained as follow:
Mass of Al = 35.64 g
Molar mass of Al = 27 g/mol
Number of mole of Al =?
Mole = mass / molar mass
Number of mole of Al = 35.64 / 27
Number of mole of Al = 1.32 moles
Thus, 1.32 moles of aluminum are present in the block of the metal.
All colors but red is being absorbed by the material.
Pressure<span> with Height: </span>pressure<span> decreases with increasing </span>altitude<span>. The </span>pressure<span>at any level in the atmosphere may be interpreted as the total weight of the </span>air<span>above a unit area at any </span>elevation<span>. At higher elevations, there are fewer </span>air<span>molecules above a given surface than a similar surface at lower levels</span>
Answer:ccccccccccccccccccccccccccccccccccccccc
Explanation:
