How many molecules of ethane (C2H6) are present in 0.249 g of C2H6?
Enter answer in scientific notation.
How many mols C2H6 do you have? That's mols = grams/molar mass.
Then 1 mol contains 6.02E23 molecules.
To calculate the number of molecules of ethane (C2H6) present in a given mass, we can use the concept of molar mass and Avogadro's number.
1. Calculate the molar mass of ethane (C2H6):
The molar mass is the sum of the atomic masses of one carbon atom (C) and six hydrogen atoms (H).
Molar mass of C2H6 = (2 * Atomic mass of C) + (6 * Atomic mass of H)
Molar mass of C2H6 = (2 * 12.01 g/mol) + (6 * 1.008 g/mol)
Molar mass of C2H6 = 30.07 g/mol
2. Convert the given mass of ethane (C2H6) into moles:
Moles = Mass / Molar mass
Moles = 0.249 g / 30.07 g/mol
Moles = 0.00828 mol
3. Calculate the number of molecules using Avogadro's number:
One mole contains 6.022 x 10^23 molecules (Avogadro's number).
Number of molecules = Moles * Avogadro's number
Number of molecules = 0.00828 mol * 6.022 x 10^23 molecules/mol
Therefore, the number of molecules of ethane (C2H6) present in 0.249 g of C2H6 is approximately 4.976 x 10^21 molecules.
To find the number of molecules of ethane (C2H6) present in 0.249 g of C2H6, you can follow these steps:
1. Calculate the molar mass of ethane (C2H6) by adding up the atomic masses of each element in the molecule.
- The atomic mass of carbon (C) is 12.01 g/mol.
- The atomic mass of hydrogen (H) is 1.01 g/mol.
- Since ethane (C2H6) has two carbon atoms and six hydrogen atoms, the molar mass is: (2 x 12.01 g/mol) + (6 x 1.01 g/mol) = 30.07 g/mol.
2. Convert the given mass of ethane (0.249 g) to moles by dividing it by the molar mass.
- Moles = Mass / Molar mass = 0.249 g / 30.07 g/mol ≈ 0.008290 mol (rounded to six decimal places).
3. Express the moles of ethane in scientific notation.
- In scientific notation form, 0.008290 mol can be written as 8.29 x 10^-3 mol (using the rules of scientific notation).
4. Calculate the number of molecules by multiplying the moles of ethane by Avogadro's number (6.022 x 10^23).
- Number of molecules = Moles x Avogadro's number = 8.29 x 10^-3 mol x 6.022 x 10^23 molecules/mol.
- Using scientific notation rules, you can multiply the coefficients (8.29 x 6.022) and add the exponents (10^-3 x 10^23) to get the final answer.
Therefore, the number of molecules of ethane (C2H6) present in 0.249 g of C2H6 is approximately 4.988 x 10^21 molecules.