How many molecules of ethane (C2H6) are present in 0.628 g of C2H6? Round your answer to three significant digits.
To determine the number of molecules, we need to use Avogadro's number (6.022 x 10^23 molecules/mol) and the molar mass of ethane (30.07 g/mol).
First, we calculate the number of moles of ethane:
moles = mass / molar mass
moles = 0.628 g / 30.07 g/mol = 0.0209 mol
Next, we convert moles to molecules using Avogadro's number:
molecules = moles * Avogadro's number
molecules = 0.0209 mol * 6.022 x 10^23 molecules/mol = 1.257 x 10^22 molecules
Rounded to three significant digits, there are 1.26 x 10^22 molecules of ethane in 0.628 g.
To find the number of molecules of ethane (C2H6) present in 0.628 g of C2H6, we can use the following steps:
1. Calculate the molar mass of ethane (C2H6):
- Molar mass of carbon (C) = 12.01 g/mol
- Molar mass of hydrogen (H) = 1.008 g/mol
- Molar mass of ethane (C2H6) = (2 * 12.01 g/mol) + (6 * 1.008 g/mol) = 30.07 g/mol
2. Convert the given mass of C2H6 to moles:
- Moles of C2H6 = mass of C2H6 / molar mass of C2H6
- Moles of C2H6 = 0.628 g / 30.07 g/mol = 0.0209 mol
3. Use Avogadro's number to convert from moles to molecules:
- Number of molecules of C2H6 = moles of C2H6 * Avogadro's number
- Avogadro's number = 6.022 x 10^23 molecules/mol
- Number of molecules of C2H6 = 0.0209 mol * 6.022 x 10^23 molecules/mol = 1.26 x 10^22 molecules
Therefore, there are approximately 1.26 x 10^22 molecules of ethane (C2H6) present in 0.628 g of C2H6.
To calculate the number of molecules of ethane (C2H6) present in 0.628 g, we need to use the concept of moles.
Step 1: Find the molar mass of ethane (C2H6)
First, let's calculate the molar mass of ethane (C2H6). The molar mass is the sum of the atomic masses of each element in the compound.
- The atomic mass of carbon (C) is approximately 12.01 g/mol.
- The atomic mass of hydrogen (H) is approximately 1.01 g/mol.
Since ethane has two carbon atoms (C2) and six hydrogen atoms (H6), the molar mass of ethane can be calculated as follows:
(2 * 12.01 g/mol) + (6 * 1.01 g/mol) = 30.07 g/mol
So, the molar mass of ethane is approximately 30.07 g/mol.
Step 2: Convert grams to moles
Now, let's convert the given mass of ethane (0.628 g) to moles. We'll use the formula:
moles = mass / molar mass
moles = 0.628 g / 30.07 g/mol
moles ≈ 0.0209 mol (rounded to four decimal places)
Step 3: Convert moles to molecules
Next, we need to convert moles to molecules of ethane. One mole of a substance contains Avogadro's number (6.022 * 10^23) of particles, which includes molecules.
To convert moles to molecules, multiply the number of moles by Avogadro's number:
molecules = moles * Avogadro's number
molecules ≈ 0.0209 mol * (6.022 * 10^23 molecules/mol)
molecules ≈ 1.258 * 10^22 molecules (rounded to three significant digits)
Therefore, there are approximately 1.258 * 10^22 molecules of ethane (C2H6) present in 0.628 g of C2H6.