1. When our Galaxy was forming why was the center dense?
Answer: <u>Stars are believed to originate as from gas clouds in space. Gravitational forces cause this gas to contract forming a dense center of gravitational force.Eventually this extreme pressure at the center of the star causes nuclear fusion reactions to occur.</u>
2. Why did hydrogen atoms collide in the dense center of the Galaxy?
Answer: <u>Compression would heat the gas to temperatures above 1,000 kelvins. Some hydrogen atoms would pair up in the dense, hot gas, creating trace amounts of molecular hydrogen. The hydrogen molecules would then start to cool the densest parts of the gas by emitting infrared radiation after they collide with hydrogen atoms.</u>
Balance the equation first:
2 Fe+6 HNO3→2 Fe(NO3)3+3H2
Then calculate mass of Iron :
4.5×3.0×3.5 cm3(1 mL1 cm3)(7.87 g Fe1 ml)=371.86 g Fe
Now use Stoichiometry:
371.86 g Fe×(1 mol Fe55.85 g Fe)×(6 mol HNO32 mol Fe)=19.97 mol HNO3
Convert moles of nitric acid to grams
19.97 mol HNO3×(63.01 g HNO31 mol HNO3)=1258.3 g HNO3
“Students studied the weather front that caused the recent hurricane”
