MgH2 + 2 H2O → Mg(OH)2 + 2 H2
Answer:
When the metal of the ionic compound has multiple oxidation states.
Explanation:
Nickel (Ni - At No 28) has multiple oxidation states* => −2, −1, 0, +1,[2] +2, +3, +4[3] (a mildly basic oxide)*. When naming compound of nickel on needs to include a roman numeral in parenthesis after the symbol of the element in order to identify which oxidation state is relevant.
examples
Nickel Halide derivatives include
NiCl => nickel(I) chloride
NiCl₂ => nickel(II) chloride
NiCl₃ => nickel (III) chloride
Such is important in that each of the compounds have different physical and chemical properties due to variations in oxidation states of nickel.
https://en.wikipedia.org/wiki/Nickel
We have to calculate the number of carbon atoms present in 2-carat pure diamond.
The number of carbon atoms present in 2-carat pure diamond is: 0.19 X 10²³ number of carbon atom.
Diamond is one allotrope of carbon. Atomic mass of carbon is 12.
Mass of one mole carbon atom is 12 g. One mole carbon contains Avogadro's number i.e, 6.023 X 10²³ number of atoms.
0.40 g diamond contains 0.40/12 moles= 0.033 moles of carbon atom.
So, number of carbon atoms present in 0.40 g diamond (i.e, 0.033 mole diamond) is 0.033 X 6.023 X 10²³= 1.98 X 10²²=0.19 X 10²³ .
Therefore, 0.19 X 10²³ number of carbon atoms are in a 2-carat pure diamond that has a mass of 0.40 g
Answer:
A severe depletion of ozone in a region of the ozone layer, particularly over Antarctica and over the Arctic. The depletion is caused by the destruction of ozone by CFCs and by other compounds, such as carbon tetrachloride (CCl4) and carbon tetrafluoride (CF4).
Explanation:
A severe depletion of ozone in a region of the ozone layer, particularly over Antarctica and over the Arctic. The depletion is caused by the destruction of ozone by CFCs and by other compounds, such as carbon tetrachloride (CCl4) and carbon tetrafluoride (CF4).