Question

Calculate the number of atoms in 156g of Al2Li

Answer 1

To calculate the number of atoms in 156g of Al2Li, we need to follow two steps. The first step is to calculate the moles in 156g, and the second step is to convert moles to atoms. Let's break it down:

Step 1: Calculate the moles in 156g of Al2Li.

The formula to convert grams to moles is 1/molar mass.

The molar mass is the total mass of all the elements in the compound.

To start, write down 156g:

156g Al2Li x 1 / molar mass

Next, let's calculate the molar mass of Al2Li:

Al(2) = 54g

Li = 7g

Al2Li = 54g + 7g = 61g

Now, we can perform the calculation:

156g of Al2Li x 1 mol / 61g = 2.56 moles (rounded to 3 significant figures)

Step 2: Convert moles to atoms.

The conversion factor for moles to atoms is Avogadro's number, which is 6.02 x 10^23 atoms per 1 mole.

Using the moles we calculated in step 1 (2.56 moles), we can convert to atoms:

2.56 moles x 6.02 x 10^23 atoms / 1 = 1.54 x 10^24 atoms

Therefore, the final answer is that there are 1.54 x 10^24 atoms in 156g of Al2Li.

Answer 2

To find the number of atoms in 156 g of Al2Li, calculate the number of moles based on the molar mass and multiply by Avogadro's number and the number of atoms per formula unit, resulting in approximately 5.52 x 10^24 atoms.

Step-by-step explanation:

To calculate the number of atoms in 156 g of Al2Li, we need to first determine the molar mass of Al2Li and then use this information to calculate the number of moles of Al2Li in the sample. Using the molar masses of aluminium (Al) and lithium (Li), we find that the molar mass of Al2Li is approximately 50.96 g/mol (2 x 26.98 g/mol for Al + 6.94 g/mol for Li).

Next, we divide the mass of the Al2Li sample by its molar mass to find the number of moles:

Number of moles of Al2Li = 156 g / 50.96 g/mol = 3.06 moles

Since the formula Al2Li indicates there are two aluminium atoms and one lithium atom per formula unit, we have a total of 3 atoms per formula unit. To find the total number of atoms, we multiply the number of moles of Al2Li by Avogadro's number (6.022 x 10^23 atoms/mol), and then by 3:

Total number of atoms in 156 g of Al2Li = 3.06 moles x 6.022 x 10^23 atoms/mol x 3 atoms/mol = 5.52 x 10^24 atoms.