Answer: e) all of these
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 
, carbon dioxide 
Mixtures are not pure substances as they consist of elements and compounds combined physically and not in any fixed ratio. Example: Air
Thus all given substances are pure substances.
Explanation:
If we compare its solubility products without any calculation then, Magnesium hydroxide is more soluble than compound A and C. Magnesium hydroxide is less soluble than compound D.
- The solubility product of magnesium hydroxide and zinc carbonate is same so it is not possible to determine whether it is more or less soluble than compound B
Answer:
2RbNO₃ + BeF₂ → Be(NO₃)₂ + 2RbF, because Be keeps a 2+ charge throughout the reaction
Explanation:
2RbNO₃ + BeF₂ → Be(NO₃)₂ + 2RbF, because Be keeps a 2+ charge throughout the reaction
Rb is a +1 cation, NO3 is a -1 anion, Be is a +2 cation and F is a -1 anion.
In writing an ionic compound the charge of the cation becomes the subscript of the anion and the charge of the anion becomes the subscript of the cation.
So the ionic compound formed between Be2+ and F- is BeF2. The ionic compound formed between Be2+ and NO3- is Be(NO₃)₂.
As there are two NO₃ on the product side it is balanced by writing a 2 coefficient before RbNO₃ on the reactant side.
And as there are two F on the reactant side it is balanced by writing a 2 coefficient before RbF on the product side.
The buffer has a pH of 9.47.
<h3>
What do you understand by pH?</h3>
The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality. Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water. Or, pH, a numerical indicator of how basic or acidic aqueous or other liquid solutions are. The phrase, which is frequently used in chemistry, biology, and agronomy, converts the hydrogen ion concentration, which typically ranges between 1 and 1014 gram-equivalents per liter, into numbers between 0 and 14.
To learn more about pH, visit"
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