MediumChemistryHigh School (11–12)The d- and f-Block Elements › Transition Elements (d-Block)Numerical
The atomic radii are 126 pm for iron, 129 pm for chromium and 175 pm for lead…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The atomic radii are for iron, for chromium and for lead. A pair can form a substitutional alloy if the radii differ by no more than of the smaller radius. Find the difference for iron and chromium, and for iron and lead, as a percentage. Then find the largest atomic radius that can replace iron within the rule.
Need a reminder? The key ideaShow
Moles = mass in g divided by molar mass in g/mol, or concentration in mol/L times volume in litres. Take every mole ratio from the balanced equation, and follow the chain one step at a time.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Iron and chromium. . This is below 15 %, so they can alloy. Stainless steel is one example.
Step 2. Iron and lead. . This is far above 15 %, so they do not alloy.
Step 3. The limit. , which is to three figures.
Answer: , and .
Check. Chromium at is under and lead at is over it.
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