A couple questions here:
1. How do you expect nitriding to change the properties of iron?
a) Nitriding makes iron stronger.
b) Nitriding makes iron weaker.
c) Nitriding makes iron more electrically conductive.
d) Nitriding makes iron less electrically conductive.
2. Calculate the relative number of atoms of each element contained in each of the following alloys. (Assume the amounts per 100 g of the alloy.)
(a) Wood's metal, which is a low-melting-point alloy used to trigger automatic sprinkler systems and is 12.5% tin, 12.5% cadmium, and 24% lead by mass in bismuth
Bi :
Cd :
Pb :
Sn
(b) a stainless steel that is 13% chromium in iron
Fe :
Cr
I have some thoughts on #1 but I can't confirm them so I'll leave that one alone.
#2 a and #2 b are the same kind of problem. Here is how you do #2a.
Take a 100 g sample.
12.5 g Sn
12.5 g Cd
24 g Pb
100 - (g Sn - g Cd - g Pb) = g Bi.
Then mols = grams/molar mass
Using mols of each, determine relative mols (in whole numbers). If you get stuck post your work and I can help you through it. All this is is finding the empirical formula for woods metal.
1. To answer this question, we need to understand what nitriding is and how it affects the properties of iron. Nitriding is a process in which nitrogen atoms are diffused into the surface of iron to form nitrides. This alters the composition and structure of the surface layer, resulting in changes in the properties of the iron.
The correct answer to this question would be:
a) Nitriding makes iron stronger.
Explanation: Nitriding introduces nitrogen into the surface of iron, forming nitrides. These nitrides are typically very hard, which increases the hardness and strength of the iron. Therefore, nitriding generally makes iron stronger.
2. To calculate the relative number of atoms of each element in the given alloys, we need to consider their mass percentages and the atomic masses of the elements involved. Here's how we can approach each alloy:
(a) Wood's metal:
- Tin (Sn): 12.5% by mass
- Cadmium (Cd): 12.5% by mass
- Lead (Pb): 24% by mass
- Bismuth (Bi): The remaining mass percentage (100% - (12.5% + 12.5% + 24%))
To calculate the relative number of atoms, we need to convert the mass percentages to moles and then use the mole ratios of the elements based on their atomic masses. The atomic masses are:
- Bi: 208.98 g/mol
- Cd: 112.41 g/mol
- Pb: 207.2 g/mol
- Sn: 118.71 g/mol
Using this information, we can calculate the relative number of atoms as follows:
Bi: (Mass percentage of Bi / Atomic mass of Bi) * 100 g
Cd: (Mass percentage of Cd / Atomic mass of Cd) * 100 g
Pb: (Mass percentage of Pb / Atomic mass of Pb) * 100 g
Sn: (Mass percentage of Sn / Atomic mass of Sn) * 100 g
(b) Stainless steel:
- Iron (Fe): 100% - 13% (complement percentage)
- Chromium (Cr): 13% by mass
To calculate the relative number of atoms, we follow a similar process as above:
Fe: (Mass percentage of Fe / Atomic mass of Fe) * 100 g
Cr: (Mass percentage of Cr / Atomic mass of Cr) * 100 g
Please let me know if you would like the specific calculations for each element, and I will be happy to provide them.