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GWHS Alloys

Last updated about 2 years ago
4 questions

Alloys

Objective:

1) Explain the difference between a pure metal, an interstitial alloy, and a substitutional alloy.
Read This!

Metals are amazing, and they are all around us. You can probably easily identify them by their shiny surfaces and tinny sound when you tap them. We use metals to run electricity through our house, manufacture our cars, and create circuits for our phones. However, most metals in their pure form are less than perfect for these jobs. Luckily, the properties of metals can be manipulated to make them more useful by adding other elements to form a mixture. These mixtures are called alloys. In this activity, you will look at two types of alloys and their properties.
Watch the video to learn about the different types of alloys! Take notes in your notebook while you watch the video.

1

Match each statement with the type of alloy that is described.

  • A mixture of iron (AR = 126 pm) and nitrogen (AR = 65 pm).
  • Are held together by metallic bonding.
  • A mixture of iron (AR = 126 pm), carbon (AR = 70 pm), and zinc (142 pm)
  • A mixture of copper (AR = 128 pm) and zinc (AR = 139 pm).
  • Similar sized atoms are substituted and take the place of the original atoms.
  • Smaller sized atoms sit in the spaces between the original atoms.
  • Substitutional alloys
  • Interstitial alloys
  • Both interstitial and substitutional alloys
1

Would substitutional alloys tend to have a density similar to, significantly greater than or significantly less than the pure metal?

1

Interstitial alloys oftentimes have a density less than the pure metal. Explain how the addition of a small, low mass atom like carbon could make the density of an interstitial alloy less than the pure metal.
Important Notes:
  • Density = mass / volume
  • Density describes how compact something is.
  • Volume measures how much space an object occupies

1

Metals are malleable because of weak bonds between atoms. This allows planes of atoms to slide past one another and into new positions. Some alloys retain their malleability while others become more rigid. Predict which type of alloy would result in a more rigid substance. Justify your reasoning.