How To Calculate The Molar Mass of a Compound - Quick & Easy!

Summary

This video explains how to calculate the molar mass of various compounds, starting with basic elements like nitrogen and fluorine, and progressing to more complex molecules like ozone, sulfur, carbon dioxide, and glucose. The video covers the process of finding atomic masses on the periodic table, multiplying by the number of atoms in a molecule, and adding the values to determine the molar mass. It also includes examples of ionic compounds, such as calcium phosphate and vanadium 5 hydrogen phosphate, showing how to determine their chemical formulas and molar masses.

Takeaways

• 😀 Molar mass is the mass of one mole of a substance, measured in grams per mole (g/mol).
• 😀 To find the molar mass of an element, refer to its atomic mass on the periodic table (e.g., nitrogen's atomic mass is 14.01 g/mol).
• 😀 The molar mass of a compound is calculated by summing the atomic masses of its constituent elements, multiplied by the number of atoms in the compound.
• 😀 Atomic masses are expressed in g/mol, and the molar mass connects mass to moles.
• 😀 For molecular compounds, calculate the molar mass by multiplying the atomic mass of each element by the number of atoms in the molecule.
• 😀 For example, the molar mass of ozone (O3) is 48 g/mol, calculated by multiplying the atomic mass of oxygen (16 g/mol) by 3.
• 😀 A compound like sulfur (S8) has a molar mass of 256.56 g/mol, as sulfur has an atomic mass of 32.07 g/mol and there are 8 sulfur atoms.
• 😀 More complex compounds like carbon dioxide (CO2) or silicon tetrafluoride (SiF4) require summing the contributions from all elements (e.g., CO2 is 44.01 g/mol).
• 😀 Glucose (C6H12O6) has a molar mass of 180.18 g/mol, derived from the masses of 6 carbon, 12 hydrogen, and 6 oxygen atoms.
• 😀 For ionic compounds, first determine the chemical formula, then calculate the molar mass by applying the atomic masses and stoichiometry, as demonstrated with calcium phosphate (Ca3(PO4)2) and vanadium 5 hydrogen phosphate (V2(HPO4)5).

Q & A

What is the molar mass of nitrogen (N) in its atomic form?

The molar mass of nitrogen (N) is 14.01 g per mole. This means that one mole of nitrogen atoms weighs 14.01 grams.

How do you calculate the molar mass of a molecule like ozone (O3)?

To calculate the molar mass of ozone (O3), first find the atomic mass of oxygen, which is 16 g per mole. Since ozone consists of three oxygen atoms, the molar mass is 3 × 16 = 48 g per mole.

What is the molar mass of sulfur (S) in its elemental form (S8)?

Sulfur (S8) consists of 8 sulfur atoms. The atomic mass of sulfur is 32.07 g per mole, so the molar mass of sulfur (S8) is 32.07 × 8 = 256.56 g per mole.

How do you calculate the molar mass of carbon dioxide (CO2)?

To find the molar mass of carbon dioxide (CO2), add the atomic mass of carbon (12.01 g) and the atomic mass of oxygen (16 g), multiplied by 2. Thus, the molar mass of CO2 is 12.01 + (2 × 16) = 44.01 g per mole.

What is the molar mass of silicon tetrafluoride (SiF4)?

To calculate the molar mass of silicon tetrafluoride (SiF4), first find the atomic mass of silicon (28.9 g) and fluorine (19 g). The molar mass is 28.9 + (4 × 19) = 104.9 g per mole.

How do you calculate the molar mass of glucose (C6H12O6)?

To calculate the molar mass of glucose, multiply the atomic mass of each element by the number of atoms of that element in the formula. For glucose, this is: 6 × 12.01 (carbon) + 12 × 1.008 (hydrogen) + 6 × 16 (oxygen), resulting in a molar mass of 180.16 g per mole.

What is the molar mass of calcium phosphate (Ca3(PO4)2)?

The molar mass of calcium phosphate (Ca3(PO4)2) can be calculated by adding the masses of calcium (40.8 g), phosphorus (30.97 g), and oxygen (16 g). With 3 calcium atoms, 2 phosphorus atoms, and 8 oxygen atoms, the molar mass is 310.18 g per mole.

How do you write the chemical formula for vanadium(V) hydrogen phosphate?

Vanadium(V) hydrogen phosphate has the formula V2(HPO4)5. The Roman numeral V indicates a +5 charge on vanadium. The hydrogen phosphate ion is HPO4 with a charge of -2, so the formula is based on balancing these charges.

How do you calculate the molar mass of vanadium(V) hydrogen phosphate (V2(HPO4)5)?

To calculate the molar mass of vanadium(V) hydrogen phosphate, first multiply the atomic masses of vanadium (50.94 g), hydrogen (1.008 g), phosphorus (30.97 g), and oxygen (16 g). For this compound, the molar mass is 581.77 g per mole.

Why is it important to understand molar mass in chemistry?

Understanding molar mass is crucial because it connects the mass of a substance with the number of moles, allowing chemists to calculate quantities of substances involved in chemical reactions, predict yields, and understand molecular composition.