The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
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<span>a. </span>
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Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
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The chemical property of mercury is that it reacts with oxygen
<span>Important information to solve the exercise :
Substance ΔHf (kJ/mol):
HCl(g)= −92.0 </span><span>kJ/mol
Al(OH)3(s)= −1277.0 </span><span><span>kJ/mol
</span> H2O(l)= −285.8 </span><span>kJ/mol
AlCl3(s) =−705.6 </span><span>kJ/mol
</span><span>Al(OH)3(s)+3HCl(g)→AlCl3(s)+3H2O(l)
reactants products
products- reactants:</span><span>
(−705.6) + (3 x −285.8) - ( −1277.0 ) - (3 x −92.0 ) = - 10.0 </span>kJ per mole at 25°C
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The digestive system of multicellular is made up of several organs that work together to break down food so that it may be used in the body. Unicellular organisms have organelles, similar to organs, which help to digest food that will be used by the cell
The boiling point of plain water is less than the boiling point of both salt and sugar water.
<h3>What is boiling point?</h3>
Boiling point can be defined as the point when the pressure exerted by the surroundings upon a liquid is equal to the pressure exerted by the vapour of the liquid.
The boiling point of plain water is 100°C which increases upon addition of solute substances such as salt and sugar.
But salts are usually made up of ionic bonds while sugar are made up of covalent bonds. This means that more energy would be required to boil salt solution due to its ionic bonds.
Therefore, the boiling point of salt water is highest following sugar water before plain water which is the lowest.
Learn more boiling point here:
brainly.com/question/14008526
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