Material science-Specification of composition

In summary, the problem involves finding the weight% of Ge that needs to be added to Si to create an alloy with 2.43x10^21 Ge atoms per cubic centimeter. The formula used is C1=(m1/m1+m2)*100%, where C1 is the concentration in weight% of material 1 and m1 and m2 are the masses of material 1 and 2, respectively. The calculated answer using this formula is 72%, but the correct answer is 11.7%. It is suggested to try problem #4.20 first or use the equation given in #4.20. This problem is from Chapter 5 of the book "Materials Science and Engineering Intro" by William D
  • #1
mugzieee
77
0
Im given this problem:
Ge forms a substitutional solid solution with Si. find the weight% of Ge, that must be added to Si to yield an alloy that contains 2.43x10^21 Ge atoms per cubic centimetr. The densities of pure Ge and Si are 5.32 and 2.33 g/cm^3, respectively.

then I have a formula that says C1=(m1/m1+m2)*100% where C1 is the concentration in weight % of material 1 and m1 is the mass of material 1, and m2 is the mass of material 2. I use this formula, and i get 72% for Ge, but the correct answer is 11.7%. does anyone know what i am doing wrong?
 
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  • #2
Is this problem from Materials Science and Engineering Intro by William D CallisteR?

If it is then it's question # 4.22. Anyway try doing #4.20 first, or just simply use the equation that's given in # 4.20.
 
  • #3
it is that book, but it is in chapter 5, not chapter 4.
 

1. What is meant by "specification of composition" in material science?

The specification of composition in material science refers to the detailed breakdown of the chemical elements and their respective proportions that make up a material. This information is crucial for understanding the properties and behavior of a material.

2. Why is it important to specify the composition of a material?

Specifying the composition of a material is important because it allows scientists to understand the behavior and properties of the material. Different compositions can result in vastly different properties, such as strength, flexibility, and conductivity. It also helps in identifying and controlling impurities that can affect the quality and performance of the material.

3. How is the composition of a material determined?

The composition of a material is determined using various analytical techniques such as spectroscopy, chromatography, and microscopy. These techniques involve analyzing the elemental and molecular makeup of a material and determining their relative proportions.

4. Can the composition of a material be changed?

Yes, the composition of a material can be changed through various methods such as alloying, which involves mixing different elements to create a new material with desired properties. Heat treatment and surface modification techniques can also alter the composition and properties of a material.

5. How does the specification of composition affect the performance of a material?

The specification of composition has a significant impact on the performance of a material. Different compositions can result in varying physical, chemical, and mechanical properties, which can affect the material's suitability for a particular application. By understanding and controlling the composition, scientists can tailor the material to meet specific performance requirements.

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