They are particular solids.
(B), because 1.0 moles would be 6.02 x 10^23 molecules. So you have half a mole.<span>
</span>
Considering the definition of percentage by mass, the mass percentage of CaCO₃ is 68.59%.
<h3>What is mass percentage</h3>
The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.
In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.
The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

<h3>Mass percentage of CaCO₃</h3>
In this case, you know:
- mass of CaCO₃: 2.62 grams
- mass of limestone: 3.82 grams
Replacing in the definition of mass percentage:

<u><em>mass percentage= 68.59 %</em></u>
Finally, the mass percentage of CaCO₃ is 68.59%.
Learn more about percentage by mass:
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1. ₉¹⁹F
2. Mg(OH)₂
3. 2H₂ + O₂ ⇒ 2H₂O
<h3>Further explanation</h3>
1. Fluorine, atomic number : 9 , mass number = 19
Symbol : ₉¹⁹F
protons=electrons=atomic number = 9
neutrons = mass number - atomic mass

Configuration : [He] 2s² 2p⁵
2. Magnesium hydroxide is an ionic compound and is a strong base consisting of 2 ions:
Positive ion: Magnesium: Mg²⁺
negative ion: Hydroxide: OH⁻
The charges of the two are crossed, so that the compound becomes:
Mg(OH)₂
3. Reaction :
H₂ + O₂ --------> H₂O
give coefficient :
aH₂ + bO₂ --------> H₂O
H, left = 2a, right 2⇒2a=2⇒a=1
O, left = 2b, right 1⇒2b=1⇒b=0.5
Reaction becomes :
H₂ + 0.5O₂ --------> H₂O x 2
2H₂ + O₂ --------> 2H₂O
Most metamorphic processes takes place few kilometers below the Earth's surface. Thus, "metamorphic rocks" are formed under conditions found few kilometers under the Earth's surface.
Sedimentary rocks are formed by the compaction of sediments. Two main groups of sedimentary rocks are clastic sedimentary rocks and chemical sedimentary rocks.
Metamorphism refers to the changes in the mineral composition of the rocks. The three agents of metamorphism are heat, pressure and water.
The conversion of one form of rock to another is referred as rock cycle. In a rock cycle, an igneous rock formed from the deposition of molten magma can get converted into sedimentary rock when igneous rock breaks down into pieces and sediments. Finally, the any sedimentary rock or igneous rock can undergo metamorphosis to form metamorphic rocks. Metamorphic rock can again form igneous rock by melting of magma followed by crystallization.