The percentage adds up to 100%.
<h3>Percentages</h3>
Mass of mixture = mass of container+mixture - mass of container = 56.779 - 54.558 = 2.221 g
CuCO3 is insoluble in water. Thus:
Mass of CuCO3 = mass of beaker and residue - mass of beaker = 78.875 - 77.575 = 1.300 g
Mass of NaCl = mass of mixture - mass of CuCO3 = 2.221 - 1.300 = 0.921 g
%NaCl (w/w) = weight of NaCl/weight of mixture = 10.921/2.221 = 41.468%
% (w/w) CuCO3 = weight of CuCO3/weight of mixture = 1.300/2.221 = 58.532%
Addition of percentages = 41.468 + 58.532 = 100%
More on percentages can be found here: brainly.com/question/24159063
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It gains or loses electrons to become like the Noble gases having 8 valence electrons to become the most stable.
The correct answer is option A. Energy cannot be created during an ordinary chemical reaction. There is no such thing as an ordinary chemical reaction. Energy cannot be created or destroyed this is according to the law of conservation of energy. It can only be transformed from one form to another form.
Most scientific questions are developed from Observations.
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