Duralin is an alloy of aluminium containing

4.5% manganese, 3.5% copper, and 0.45%
magnesium. How much magnesium is present
in a 90 g sample of this alloy?
Answer in units of mol

What is .0045*90? then because that is in grams, divide that by the atomic mass of Mg.

6555

To find the amount of magnesium present in a 90 g sample of the Duralin alloy, we need to first understand the composition of the alloy.

The composition states that Duralin contains 0.45% magnesium. This means that for every 100 grams of Duralin alloy, there is 0.45 grams of magnesium.

To convert the mass of magnesium from grams to moles, we need to know the molar mass of magnesium. The molar mass of magnesium is approximately 24.31 g/mol.

Now we can calculate the amount of magnesium in moles:

1. Calculate the mass of magnesium in the 90 g sample of Duralin alloy:
Mass of magnesium = (0.45 g / 100 g) * 90 g = 0.405 g

2. Convert the mass of magnesium to moles using the molar mass of magnesium:
Moles of magnesium = Mass / Molar mass = 0.405 g / 24.31 g/mol ≈ 0.0167 mol

Therefore, there is approximately 0.0167 mol of magnesium present in a 90 g sample of the Duralin alloy.