Short answers, pulled from the story.
Roger Chaffee died on the 27th of January, 1967, from asphyxia caused by toxic gases produced during a fire inside the Apollo 1 command module during a pre-launch test at Cape Kennedy Air Force Station. A power surge believed to have caused an electrical short ignited the fire in the pure oxygen atmosphere. Chaffee lost consciousness from lack of oxygen, which sent him into cardiac arrest; burns also contributed to his death.
Chaffee was the third-ranking pilot on Apollo 1, joining Command Pilot Virgil Grissom and Senior Pilot Ed White. His primary role during the pre-launch test was to maintain communications with the blockhouse. He was the youngest American astronaut to be assigned to a spaceflight mission at the time of his selection.
Following the Apollo 1 fire in 1967, NASA redesigned the command module extensively. The cabin atmosphere at launch was changed from pure oxygen to a sixty percent oxygen and forty percent nitrogen mixture. The astronauts' nylon spacesuits were replaced with beta cloth woven from fiberglass and coated with Teflon. Flammable cabin materials were replaced with self-extinguishing ones, and plumbing and wiring received protective insulation.
Chaffee received the Air Medal for his reconnaissance flights with Heavy Photographic Squadron 62, and was posthumously awarded a second Air Medal. He and Ed White were posthumously awarded the Congressional Space Medal of Honor in 1997. He was inducted into the International Space Hall of Fame in 1983 and the U.S. Astronaut Hall of Fame on the 4th of October, 1997, and received the NASA Ambassador of Exploration Award in 2007.
Chaffee attended the Illinois Institute of Technology briefly before transferring to Purdue University in the autumn of 1954. He graduated from Purdue in 1957 with a Bachelor of Science in aeronautical engineering, with distinction. He later pursued a Master of Science degree in reliability engineering at the U.S. Air Force Institute of Technology at Wright-Patterson Air Force Base.
Chaffee is memorialized by the Chaffee Crater on the far side of the Moon, Chaffee Hill on Mars, and the Roger B. Chaffee Planetarium and Roger B. Chaffee Boulevard in Grand Rapids, Michigan. His name appears on the Fallen Astronaut plaque left on the Moon in 1971 by the crew of Apollo 15, and on the Space Mirror Memorial dedicated in 1991. The Roger B. Chaffee scholarship has been awarded annually since 1967 to Kent Intermediate School District students pursuing math and science careers.