Question 1: Define an alloy and explain how it differs from a pure metal.

Answer: An alloy is a mixture of two or more elements, at least one of which is a metal, that are combined to enhance properties like strength or corrosion resistance. Unlike pure metals, alloys have a varied composition that gives them different physical properties.

Question 2: Describe the mechanism by which metallic bonding allows metals to be malleable and ductile.

Answer: Metallic bonding involves a 'sea' of delocalized electrons around metal cations, which allows metal atoms to slide past each other without breaking bonds, making metals malleable and ductile.

Question 1: An alloy contains 70% copper and 30% zinc by mass. If a sample weighs 150 grams, how many grams of copper and zinc are in the alloy?

Answer: Copper: 105 grams; Zinc: 45 grams

Question 1: Describe a simple experiment to test the corrosion resistance of an alloy compared to pure aluminum. Include variables to be controlled and safety precautions.

Answer: The experiment involves exposing samples of alloy and pure aluminum to a corrosive environment like saltwater for a fixed period. Variables to control include temperature, exposure time, and salt concentration. Safety precautions include wearing gloves and goggles, handling corrosive solutions carefully, and disposing of waste properly.

Question 1: A forensic scientist finds a piece of metal scrap at a crime scene that, upon analysis, shows high resistance to corrosion and contains 85% iron and 15% carbon. What alloy could this be, and why is this property significant in forensic analysis?

Answer: This could be cast iron, which is an alloy of iron and carbon. Its high corrosion resistance and specific composition help forensic scientists identify the material's origin or manufacturing process.

Question 1: Explain why alloys are generally stronger than pure metals.

Answer: Alloys are stronger because the mixture of different elements creates a more complex structure that resists deformation and prevents layers from sliding past each other easily.

Question 2: Which of the following is NOT a typical property of alloys? A) Increased strength B) Reduced corrosion resistance C) Improved durability D) Enhanced appearance

Answer: B) Reduced corrosion resistance

Question 1: In forensic science, alloys are often used to identify evidence from crime scenes. Explain how the unique properties of specific alloys can help forensic investigators determine the origin or manufacturing process of metal evidence.

Answer: Alloys have unique compositions and properties such as hardness, corrosion resistance, and appearance that can be matched to specific manufacturing processes or sources. By analyzing these properties, forensic scientists can trace the origin of metal evidence, link it to particular industries or products, and build a case based on material evidence.