The amount of Mg(OH)2 present after the reaction is complete is 0.136 moles of Mg(OH)2.
The equation of the reaction is;
2HNO3(aq) + Mg(OH)2(aq) -------> Mg(NO3)2(aq) + 2H2O(l)
Number of moles of Mg(OH)2 = 8.00 g/58 g/mol = 0.138 moles
Number of moles of HNO3 = 0.205 M × 24.2 mL/1000 = 0.00496 moles
Given that;
2 moles of HNO3 reacts with 1 mole of Mg(OH)2
0.00496 moles of HNO3 reacts with 0.00496 moles × 1 mole /2 moles = 0.00248 moles of Mg(OH)2
Hence, Mg(OH)2 is the reactant in excess.
The amount of Mg(OH)2 remaining = Amount present - Amount reacted
Hence; 0.138 moles - 0.00248 moles = 0.136 moles of Mg(OH)2
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The statement correct about bonding is the release of energy in bond formation, and is exothermic. Thus, option C is correct.
The bonds have been defined as the sharing of electrons between atoms for the stabilization and forming compounds. The formation and breaking of the bond results in the absorption and release of the energy.
<h3>Endothermic and Exothermic reaction</h3>
The reaction in which the energy has been released has been termed as exothermic reaction. The reaction in which energy is absorbed is termed as endothermic system.
The bonds are stable, and to break the bond energy has to be provided to the system. The energy will result in the delocalization of electrons and thereby breaking of bonds.
Since energy has been absorbed by the system during breaking of bonds, the reaction has been an endothermic reaction.
The formation of the bond has been releases the energy in the system and is an exothermic reaction. Thus, option C is correct.
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Answer:
Electronegativity = 1.87.
Ionic radius = 109 pm.
Atomic radius = -39 pm
First ionization energy = 410 kJ/mol
Explanation:
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In this case, since electronegativity, ionic radius, atomic radius and first ionization energy are periodic properties that have specific trends, we can summarize it by realizing that oxygen and beryllium belong the same period 2 and differ in group, 6A and 2A respectively.
In such a way, the required comparison is written below:
Electronegativity = 3.44 (oxygen) - 1.57 (beryllium) = 1.87.
Ionic radius = 140 pm (oxygen)- 31 pm (beryllium) = 109.
Atomic radius = 73 pm (oxygen) - 112 pm (beryllium) = -39 pm
First ionization energy = 1310 kJ/mol (oxygen) - 900 kJ/mol (beryllium) = 410 kJ/mol
It means that electronegativity, ionic radius and first ionization energy increases from left to right whereas the atomic radius from right to left.
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The correct answer is A. Brainliest would be much appreciated.
Answer:
To check if it's properly cleaned.
Explanation:
When you finish using a microscope, you have to take out all your samples you were using and make sure it is completely clean so that no further contamination affects future sample analysis.
Also when you begin to use it, make sure it is clean so that when you analyze your sample(s) are free from other unexpected agents.
