<h2>Answer : Law of conservation of mass</h2><h3>Explanation :</h3>
The law of conservation of mass states that in any reaction mass is neither created nor lost it has to remain constant in a system.
In this case, when the reaction setup was done in normal way the mass was lost in surrounding was not considered nor being calculated; whereas when the reaction was studied in a closed system where the gas was collected after the reaction the mass changes was noted down which helped to prove the point of law of conservation of mass and energy.
One can consider an example of soda can where the carbonated drink contains pressurized carbon dioxide gas. when opened the gas bubbles gets lost into the surroundings and we don't measure the mass changes. Instead if the soda can was opened in such a way where the gas evolved was measured then the mass changed would remain the same.
Answer:
C) the study of the composition of the atom.
Explanation:
A research can be defined as a systematic investigation or careful consideration of study with respect to a particular problem using scientific methods such as collection of data, documenting critical information, analysis of data, and the establishment of facts in order to reach new conclusions.
Similarly, a basic research is an approach to research that's typically theoritical and it's aimed at developing a theory, searching for the truth or gain a better understanding about a phenomenon, subject, or basic laws on nature.
In this context, an example of basic research is the study of the composition of the atom.
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
The molarity of a solution in which 55. 49 g of calcium chloride is dissolved in enough water to make 500. ml of solution is 1M.
<h3>What is molarity? </h3>
It is defined as number of moles of solute divided by volume of solution.
Given,
Mass of CaCl2 =55.49g
Molar mass of CaCl2 =40+35+35=110g
Mole= given mass/ molar mass
= 55.49/110=0.50mol.
Now, putting all values we get the molarity
Molarity =0.5×1000/500=1M
Thus, the molarity of given solution is 1M.
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