Understanding Phase Diagrams and Alloy Composition

The video tutorial explains how to solve a problem involving a lead-tin alloy. Initially, the alloy is 90% lead and 10% tin, heated to 250°C in a single-phase region. The task is to achieve a 50% liquid and 50% solid state. Part A involves heating the alloy to around 290°C while keeping the composition constant. Part B requires adding tin to maintain the temperature at 250°C, using the lever rule to find the new composition and calculate the additional tin needed.

What is the initial composition of the alloy in terms of lead and tin?

• 80% lead and 20% tin

• 90% lead and 10% tin

• 95% lead and 5% tin

• 85% lead and 15% tin

At what temperature is the alloy initially heated to place it in a single-phase region?

• 300 degrees Celsius

• 250 degrees Celsius

• 350 degrees Celsius

• 200 degrees Celsius

What is the approximate temperature required to achieve a 50% liquid and 50% solid state by heating?

• 330 degrees Celsius

• 310 degrees Celsius

• 290 degrees Celsius

• 270 degrees Celsius

What is the initial weight percent of tin in the alloy?

• 5%

• 10%

• 15%

• 20%

What is the composition of the solid form at 250 degrees Celsius?

• 22% tin

• 18% tin

• 14% tin

• 10% tin

What is the composition of the liquid form at 250 degrees Celsius?

• 33% tin

• 30% tin

• 28% tin

• 36% tin

What rule is used to determine the new composition for the desired phase state?

• Dalton's Law

• Gibbs Rule

• Phase Rule

• Lever Rule

What is the new composition required to achieve a 50% solid and 50% liquid state?

• 20.5% tin

• 21.5% tin

• 22.5% tin

• 23.5% tin

How much tin was initially present in the sample?

• 0.15 kg

• 0.20 kg

• 0.10 kg

• 0.25 kg

How much additional tin needs to be added to achieve the new composition?

• 0.364 kg

• 0.164 kg

• 0.264 kg

• 0.464 kg