A sample of metallic element X, weighing 4.315 g, combines with 0.4810 L of Cl2 gas (at normal pressure and 20.0¢ªC) to form the metal chloride with the formula XCl. If the density of Cl2 gas under these conditions is 2.948 g/L, what is the mass of the chlorine? The atomic weight of the chlorine is 35.453 amu. What is the atomic weight of X? what is the identity of X
2.948 g/L x 0.4810L = ?? grams.
Convert ??grams t moles. moles = grams/molar mass.
.........2X + Cl2 ==> 2XCl
Set up an ICE chart. YOu know Cl2 is? moles; then twice that must be mols X and n = grams/molar mass. Solve for molar mass. Look on the periodic table to identify the element.
To find the mass of chlorine, we need to calculate the number of moles of Cl2 gas using its density. Once we have the number of moles of Cl2, we can multiply it by the molar mass of chlorine to find the mass.
Step 1: Convert the volume of Cl2 gas to moles.
We know the volume of Cl2 gas is 0.4810 L and its density is 2.948 g/L. Using the formula density = mass/volume, we can calculate the mass of Cl2 gas:
mass = density * volume
mass = 2.948 g/L * 0.4810 L = 1.417768 g
Step 2: Convert the mass of Cl2 gas to moles.
Now let's calculate the number of moles of Cl2 using its molar mass. The molar mass of Cl2 is 2 * 35.453 amu = 70.906 amu.
moles of Cl2 = mass of Cl2 / molar mass of Cl2
moles of Cl2 = 1.417768 g / 70.906 g/mol = 0.020 moles
Step 3: Calculate the atomic weight of X.
The formula of the metal chloride is XCl. The molar mass of X, denoted as MX, can be calculated using the following equation:
molar mass of XCl = atomic weight of X + atomic weight of Cl
molar mass of XCl = MX + 35.453 amu
Since we know that 4.315 g of XCl forms from 0.020 moles of Cl2, we can calculate the molar mass of XCl using the formula:
molar mass of XCl = mass of XCl / moles of XCl
mass of XCl = 4.315 g
moles of XCl = 0.020 moles
molar mass of XCl = 4.315 g / 0.020 moles = 215.75 g/mol
Substituting this value into the previous equation, we have:
215.75 g/mol = MX + 35.453 amu
Solving for MX:
MX = 215.75 g/mol - 35.453 amu = 180.297 g/mol
Therefore, the atomic weight of X is approximately 180.297 g/mol.
To determine the identity of X, we can refer to the periodic table and identify an element whose atomic weight is close to 180.297 g/mol. From the periodic table, we find that the element with an atomic weight closest to 180.297 g/mol is Platinum (Pt).
Therefore, X is most likely the element Platinum (Pt).