2. Alloys

3. Gold 24 karat gold 18 karat gold 14 karat gold Gold Copper Silver 18 / 24 atoms Au 24 / 24 atoms Au 14 / 24 atoms Au

4. Solid Brass An alloy is a mixture of metals. Brass = Copper + Zinc Solid brass homogeneous mixture a substitutional alloy Copper Zinc

5. Brass Plated Brass = Copper + Zinc Brass plated heterogeneous mixture Only brass on outside Copper Zinc

6. Hardened Steel Iron Carbon Steel a interstitial alloy

7. Brass a substitutional alloy Copper Zinc Carbon steel an interstitial alloy Carbon Iron

8. Steel Alloys Stainless steel Tungsten hardened steel Vanadium steel We can engineer properties –Add carbon to increase strength –Too much carbon  too brittle and snaps –Too little carbon  too ductile and iron bends Tensile strength Force is added

9. Galvanized Nails and Screws Zinc coating prevents rust –Use deck screws for any outdoor project Iron will rust if untreated –Weaken and break

10. Nitinol Wire Alloy of nickel and titanium Remembers shape when heated Applications: surgery, shirts that do not need to be ironed.

11. Properties of Matter Electrical Conductivity Heat Conductivity Density Melting Point Boiling Point Malleability Ductility

12. Buried in Ice Article KeysKeys Buried In Ice ChemMatters April 1994 Questions Buried In IceBuried In Ice ChemMatters April 1994 Questions http://www.unit5.org/chemistry/Matter.html