B.it is not balanced for charge or for number of atoms.
The answer is <span>The components of a homogeneous mixture are evenly distributed.
In a homogeneous mixture, all components are evenly distributed. They are known as solutions. In a heterogeneous mixture, components are not evenly distributed. It consists of visibly different components. For example, milk is the homogeneous mixture, you cannot see its particles. But milk and cereals are the heterogeneous mixtures.</span>
Answer:
Approximately 75%.
Explanation:
Look up the relative atomic mass of Ca on a modern periodic table:
There are one mole of Ca atoms in each mole of CaCO₃ formula unit.
- The mass of one mole of CaCO₃ is the same as the molar mass of this compound:
. - The mass of one mole of Ca atoms is (numerically) the same as the relative atomic mass of this element:
.
Calculate the mass ratio of Ca in a pure sample of CaCO₃:
.
Let the mass of the sample be 100 g. This sample of CaCO₃ contains 30% Ca by mass. In that 100 grams of this sample, there would be 
of Ca atoms. Assuming that the impurity does not contain any Ca. In other words, all these Ca atoms belong to CaCO₃. Apply the ratio 
:
.
In other words, by these assumptions, 100 grams of this sample would contain 75 grams of CaCO₃. The percentage mass of CaCO₃ in this sample would thus be equal to:
.
The presence of hydrogen and hydroxyl ions determines the acidic and basic nature of a solution.
<h3>What determine acidic and basic nature of a solution?</h3>
The use of the pH scale is one way of determining the acidic and basic nature of solution. If the pH of a solution is less than 7, it is considered as acidic and if the pH is 7, the solution is neutral.
While if the pH is greater than 7,the solution is basic so we can conclude that the presence of hydrogen and hydroxyl ions determines the acidic and basic nature of a solution.
Learn more about substance here: brainly.com/question/2901507
