Isomer Enumerator wins Rep. Summer Lee’s 2025 Congressional App Challenge in Pennsylvania’s 12th District
Rep. Summer Lee has named Jeffery Zhang of Upper Saint Clair High School as the winner of the 2025 Congressional App Challenge in Pennsylvania’s 12th District. Their app Isomer Enumerator generates and enumerates all possible linear, constitutional isomers of a molecule, promoting scientific discovery and drug development.
When asked what inspired the creation of Isomer Enumerator, Jeffery Zhang said, “Last year in AP chemistry class, my teacher explained that the number of isomers a molecule had was very difficult to count. I was surprised when this seemingly obvious problem had no solution. When I was researching computational chemistry, I came across an article by UIUC stating that a 20-atom molecule could have 10^6 different arrangements. I realized that many isomers out of the 10^6 neglected bonding rules; a lot of these molecules didn’t make sense chemically. I was inspired to write an app that generates molecules based on chemically realistic attributes.
“My mathematical background also gave me inspiration. I have always been interested in combinatorics. In middle school, our math class had worksheets called ‘Brainsweats’, which were meant to enhance our critical thinking. I remember drawing diagrams, labeling how many apples Sally could give to Adam, and how many oranges they could exchange. In high school, I furthered this through taking Concepts of Mathematics at Carnegie Mellon. I learned techniques like double counting and permutations. The spark for this project came when I saw this as a natural combinatorics and graph theory problem, as the molecule was a large graph, and atoms were different nodes and edges.”
The 2025 Congressional App Challenge marked another record-setting year for the program. A total of 394 Members of the U.S. House of Representatives hosted App Challenges in their congressional districts, the highest level of participation in the program’s history. More than 13,800 students from across the country participated, submitting over 4,600 original apps focused on real-world challenges ranging from health and accessibility to education, sustainability, and civic engagement.
The Congressional App Challenge is an official initiative of the U.S. House of Representatives that encourages middle school and high school students to learn to code, explore computer science, and build practical technology solutions for their communities. Each participating Member of Congress selects a winning app from their district, and winning teams are invited to showcase their projects to Members of Congress, staff, and industry leaders at the annual #HouseOfCode celebration on Capitol Hill.
The Challenge is proudly bipartisan and reflects a shared commitment to expanding access to STEM education and preparing the next generation of American innovators for the future workforce. The program is a public-private partnership made possible through funding from the Broadcom Foundation, AWS, Infosys Foundation USA, theCoderSchool, Apple, and others.
The 2026 Congressional App Challenge will launch in May, and eligible students can pre-register for the competition now.