Atomic mass Ca = 40.078 a.m.u
40.078 g -------------------- 6.02x10²³ atoms
72.8 g ---------------------- ??
72.8 x ( 6.02x10²³) / 40.078 =
4.38x10²⁵ / 40.078 = 1.093x10²⁴ atoms
hope this helps!
Explanation:
There are two aspects of a reaction:
Thermodynamics:
Combustion of the compound is reaction with oxygen.
The carbohydrates contain more content of oxygen as compared to fats.
Hence, carbohydrates have lot of oxygen content which are already partially oxidized as compared to fats. Hence, combustion of the carbohydrates is a faster process.
Kinetics:
The molecular reacts also shows that the combustion of the carbohydrates is a faster process.
Answer : The correct option is, (3) change states of matter.
Explanation :
Latent heat : It is defined as the heat required to convert the solid into liquid or vapor and a liquid into a vapor without changing the temperature.
There are two types of latent heat.
(1) Latent heat of fusion
(2) Latent heat of vaporization
Latent heat of fusion : It is defined as the amount of heat energy released or absorbed when the solid converted to liquid at atmospheric pressure at its melting point.
Latent heat of vaporization : It is defined as the amount of heat energy released or absorbed when the liquid converted to vapor at atmospheric pressure at its boiling point.
Hence, latent heat is used to change states of matter.
<u>Answer:</u> The correct answer is the mass number of the most common isotope of the element is 24.
<u>Explanation:</u>
We are given:
An element having atomic number 12 is magnesium and atomic mass of the element is 24.305
The image corresponding will be 
The number '24.305' is the average atomic mass of magnesium element.
Average atomic mass is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:

Average atomic mass of magnesium = 24.305 amu
As, the average atomic mass of magnesium lies closer to the mass of Mg-24 isotope. This means that the relative abundance of this isotope is the highest of all the other isotopes.
The 'Mg-24' isotope is the most common isotope of the given element.
Hence, the correct answer is the mass number of the most common isotope of the element is 24.
<h3>
Answer:</h3>
The total concentration of ions in a 0.75 M solution of HCl is 1.5 M
That is; 0.75 M H⁺ and 0.75 M Cl⁻
<h3>
Explanation:</h3>
- Concentration or molarity is the number of moles of a compound or an ion contained in one liter of solution. It is measured in moles per liter (M).
- The concentration of ions making a compound is determined by the ratio of moles of the compound and the constituents ions.
- For instance, HCl dissociates to give H⁺ and Cl⁻
HCl(aq) → H⁺(aq) + Cl⁻(aq)
- Therefore, since the mole ratio between HCl and the constituent ions H⁺ and Cl⁻ is 1:1, then 0.75 M of HCl dissociates to give 0.75 M H⁺ and 0.75 m Cl⁻
- Hence the total concentration of ions in a 0.75 M solution of HCl is 1.5 M (0.75 M H⁺ and 0.75 M Cl⁻)