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Atomic Mass Calculator + Online Solver With Free Steps

The Atomic Mass Calculator is used to calculate the atomic mass of an atom or molecule. It also provides the molar mass and the relative atomic mass of a given atom.

The calculator takes the chemical formula of an atom or molecule as input and outputs the required atomic mass.

To understand the atomic mass, it is important to know the sub-atomic particles in an atom. These sub-atomic particles are electrons, protons, and neutrons. The electrons and protons make the atomic mass of an atom.

The calculator also takes compounds as input. Compounds are substances with different atoms in different quantities bonded by chemical bonds. Molecules have the same atoms but compounds have different sets of atoms.

What Is an Atomic Mass Calculator?

An atomic mass calculator is an online tool that computes the atomic mass of a given atom or molecule and provides it in different unit conversions. It also calculates the molar mass M and relative atomic mass Ar.

The atomic mass is also known as the mass number. The number of protons and neutrons in an atom defines the mass number of that atom. The formula for atomic mass or mass number of an atom is:

Atomic mass = No. of protons + No. of neutrons

Protons are positively-charged particles whereas neutrons have no charge. Both the protons and neutrons lie inside the nucleus of an atom. The number of protons makes the atomic number of the atom.

The nucleus lies in the center of the atom and constitutes all the atomic mass of an atom. The electrons, which are negatively charged particles, revolve around the nucleus in circular orbits.

This calculator also computes the molar mass of an atom. The molar mass comes from the concept of “mole.” One mole of a substance contains $6.022 × 10^{23}$ particles. $6.022 × 10^{23}$ is Avogadro’s number NA.

The calculator also calculates the relative atomic mass of an atom. The relative atomic mass is a relative relation of the atomic mass of an atom to a standardized atomic mass. The standard atomic mass is the mass of the carbon-12 atom.

This calculator not only displays the atomic mass in u but also provides the quantity in other units. The atomic mass is also provided in units of daltons, kilo-daltons, grams, kilograms, and chemical atomic mass units.

These unit conversions prove beneficial for the user as it gives a variety of outputs for the atomic mass.

How To Use the Atomic Mass Calculator

The user can use the atomic mass calculator by following the steps given below:

Step 1

The user should first input the chemical formula for an atom, molecule, or compound for which it requires the mass number. It should be entered in the block with the title “Enter the Chemical Formula.”

The chemical formula set by the calculator by default is $C_6H_6$. It is a compound known as benzene, having six atoms of carbon and six atoms of hydrogen.

Step 2

After entering the chemical formula, the user should press the tab “Calculate Atomic Mass.” The calculator processes the chemical formula and computes the results.

Output

The output displayed by the calculator shows the following blocks in the output window:

Input Interpretation

The calculator interprets the input given by the user and displays it in this window. It displays the formula of atomic mass for the input atom. The formula for the atomic mass of a compound is also displayed in this window.

Result

The result displays the atomic mass of the input atom. The molecular mass for the input molecule or compound is also displayed in this window.

The mass number is displayed in “unified atomic mass units” u which is the unit for atomic mass.

Unit Conversions

The calculator also displays the atomic mass in various units through multiple unit conversions. The units of atomic mass are daltons, kilo-daltons, grams, kilograms, and chemical atomic mass units.

The atomic mass unit amu or u is also known as dalton Da. Kilo-dalton kDa is obtained by multiplying the atomic mass in daltons by 0.001.

The atomic mass can also be expressed in grams. One atomic mass unit is equal to $(1.66 × 10^{-24})$ grams. It can be expressed as:

 amu = 1.66 × $10^{-24}$ g 

By multiplying the atomic mass in $amu$ by $(1.66 × 10^{-24})$, the calculator converts the atomic mass into grams. It can be converted into kilo-grams kg by multiplying the atomic mass in grams by 0.001.

Corresponding Quantities

This window shows the calculations of relative atomic mass and molar mass for the input atom.

The relative atomic mass Ar of an atom is the mass of the given atom in ratio to the mass of the carbon-12 atom. amu is the atomic mass unit. The calculator displays amu as u.

The formula to calculate the relative atomic mass is:

\[ A_r = \frac{(m_a)(N_A)}{M_u} \]

Here,

\[ m_a = \frac{ \text{Mass in grams}}{ \text{Number of particles} } \]

And,

\[ N_A = \text{Avagadro’s number} = 6.022 × 10^{23} \]

Also, Mu is the unit molar mass. Its value is taken as 1. Ar is simply a ratio and therefore has no units.

The molar mass of an atom is the mass of one mole of an atom. The formula to calculate the molar mass M is:

M = (ma)(NA) 

The calculator displays the unit of molar mass in grams/mole.

This calculator proves handy for the chemistry students as it is simple to use and gives the atomic mass, molar mass, and relative atomic mass of an atom.

Solved Examples

The following examples are some of the solved examples through the atomic mass calculator.

Example 1

Find the atomic mass of chlorine and express the atomic mass in various units. Also, calculate the relative atomic mass and molar mass of the atom of chlorine.

Solution

The user should enter the chemical formula for an atom of chlorine. It is represented by Cl.

After pressing “Calculate Atomic Mass”, the output window shows the following results.

The input interpretation shows the name of the element “chlorine” which the calculator assumed from the entered symbol Cl.

The results window shows the atomic mass of Cl to be 35.45 u.

The unit conversions window shows the following outputs:

Atomic mass of Cl in daltons = 35.45 Da 

Atomic mass of Cl in kilo-daltons = 0.03545 kDa

Atomic mass of Cl in grams = 5.887 × $10^{-23}$ g 

Atomic mass of Cl in kilo-grams = 5.887 × $10^{-26}$ kg 

It also shows the atomic mass as “35.45 chemical atomic mass units” but it is the unit officially disapproved.

The relative atomic mass Ar of Cl is given by the calculator as:

Ar = 35 

The molar mass for the atom of chlorine is displayed as:

M = 35 g/mol

Example 2

For the atom of iron, find the atomic mass and express it in various units. Also, compute the relative atomic mass and molar mass of the atom of iron.

Solution

Enter the chemical formula for an atom of iron. The symbol for iron is Fe.

After entering the symbol, press “Calculate Atomic Mass” in the calculator’s input window. The following results will be shown in the output window.

The calculator shows the input interpretation in which it assumes the entered element. It displays “iron” which it assumes from the input symbol Fe.

The results window displays the atomic mass of Fe to be 55.845 u.

The calculator also shows the unit conversions window as follows:

Atomic mass of Fe in daltons = 55.845 Da 

Atomic mass of Fe in kilo-daltons = 0.055845 kDa \

Atomic mass of Fe in grams = 9.2733 × $10^{-23}$  g 

Atomic mass of Fe in kilo-grams = 9.2733 × $10^{-26}$ kg 

The result is also displayed as “55.847 chemical atomic mass units” but this unit is now officially disapproved.

The relative atomic mass Ar of Fe is computed by the calculator and displayed as:

Ar = 56

The molar mass for the atom of iron Fe is displayed as:

M = 56 g/mol 

Example 3

$C_{6} H_{12} O_{6}$ is the chemical formula for Glucose. Calculate the atomic mass of glucose.

Solution

The user enters the chemical formula for glucose in the input tab. It is $C_{6} H_{12} O_{6}$. The user submits the input by pressing “Calculate atomic mass.”

The output window shows the input interpretation which is similar to the entered compound. It shows the result of the atomic mass of glucose as follows:

\[ \text{Atomic mass of} \ C_6 H_{12} O_6 = 4.49 × 10^{24} \ u^3 / cm^3 \]

The unit of atomic mass is $u^3 / cm^3$, which is “unified atomic mass units cubed per centimeter cubed.”

The unit conversions tab shows the following output:

\[ \text{Atomic mass of} \ C_6 H_{12} O_6 \ \text{in} \ kg^3 / m^3 = 2.058 × 10^{-50} \ kg^3 / m^3 \]

$(kg^3 / m^3)$ represents “kilo-grams cubed per meter cubed.”

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