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Stainless steel is an alloy of iron containing 5 percent nickel and 0.175 percent chromium. How many atoms of nickel are present in a 84 g sample of this alloy?

Answer in units of atoms

Verified Answer :

First you need to work out what mass of 84g of stainless steel is nickel, and because there's 5% you can simply divide by 20, giving 4.2g

For this you can use the equation \(Moles= \frac{Mass}{Mr}\)

The mass, as was worked out previously, is 4.2g
The Mr, which is found on the periodic table, is 28

Moles = \(\frac{4.2}{28}\) = 0.15mol

1mol = 6.023 x \(10^{23}\) atoms

So, 0.15mol = 0.15 x 6.023 x \(10^{23}\) = 9.0345 x \(10^{22}\) atoms

First you need to work out what mass of 84g of stainless steel is nickel, and because there's 5% you can simply divide by 20, giving 4.2g

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