how do i find the mass number of chemicals
I would think that you would add up the components masses (molecular masses [from periodic table) that make up the chemical...
like...HCl (H= 1.008g/mol, Cl= 35.45g/mol) added= 36.458g/mol
hope this helps=)
Elements have a mass number. Compounds have molar masses but not mass numbers in the strict sense of the term. The mass number of an element is the number of protons + neutrons. For example, oxygen has an atomic number of 8 meaning it has 8 protons in the nucleus If we are discussing 16O, then 16 is the mass number (and it would have 8 neutrons).
To find the molar mass of a compound (which is the mass of one mole of the compound in grams), you need to know the chemical formula and the atomic masses of the elements in the compound.
Here's the step-by-step process:
1. Determine the chemical formula of the compound. This gives you the number and types of elements present.
2. Refer to the periodic table to find the atomic masses of each element in the compound. Atomic masses are usually given in atomic mass units (amu) or grams per mole (g/mol).
3. Multiply the atomic mass of each element by the number of atoms of that element in the compound (as indicated by the subscript in the chemical formula).
4. Add up the individual masses from step 3 to get the molar mass of the compound.
For example, let's find the molar mass of water (H₂O):
- Hydrogen (H) has an atomic mass of approximately 1.008 g/mol.
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol.
Multiplying the atomic mass of hydrogen by 2 (since there are two hydrogen atoms in water) and adding it to the atomic mass of oxygen gives us the molar mass of water:
Molar mass of H₂O = (2 * 1.008 g/mol) + 16.00 g/mol = 18.02 g/mol.
So, the molar mass of water is approximately 18.02 grams per mole.
Remember to use the accurate atomic masses from the periodic table for precise calculations.
To find the molar mass of a compound, you need to sum up the atomic masses of each element in the compound. Here's a step-by-step process on how to do it:
1. Identify the elements present in the compound and determine their atomic masses. You can find the atomic masses of elements on the periodic table.
2. Determine the number of atoms of each element in the compound by looking at the subscript numbers in the chemical formula. For example, in H2O (water), there are 2 hydrogen atoms and 1 oxygen atom.
3. Multiply the atomic mass of each element by the number of atoms present in the compound. This will give you the mass contribution of each element to the molar mass.
4. Add up the mass contributions of each element to obtain the molar mass of the compound.
Let's use an example to illustrate the process. Take water (H2O) as an example:
Hydrogen (H):
- Atomic mass: 1.008 g/mol
- Number of atoms: 2
Oxygen (O):
- Atomic mass: 16.00 g/mol
- Number of atoms: 1
Now, calculate the mass contribution of each element:
Hydrogen (H): 1.008 g/mol x 2 = 2.016 g/mol
Oxygen (O): 16.00 g/mol x 1 = 16.00 g/mol
Add up the mass contributions:
2.016 g/mol + 16.00 g/mol = 18.016 g/mol
Therefore, the molar mass of water (H2O) is 18.016 g/mol.
Remember to check the units when performing calculations, as molar mass is usually expressed in grams per mole (g/mol).