Answer:
Physical and chemical changes can occur almost everywhere, even in our bodies! Food must be broken down into a form that our cells can use. When we eat, our bodies physically break down food into small pieces. Our bodies also chemically break down those small pieces of food into tiny organic molecules.
Explanation:
<span>Symbol- Cr
Oxidation States: 6, 3, 2, 0
Chromium is unstable in oxygen, it immediately produces a thin oxide layer that is impermeable to oxygen and protects the metal below. </span>
I think B
Hope this helps!
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:
4.70 moles of water have mass of 84.6g
Explanation:
Given data:
Number of moles of water = 4.70 mol
Mass in gram = ?
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of water is 18 g/mol
Mass = 4.70 mol × 18 g/mol
Mass = 84.6 g
Thus, 4.70 moles of water have mass of 84.6g.
