During which stage of technological design are prototypes built

If 3.52 L of nitrogen gas and 2.75 L of hydrogen gas were allowed to react, how many litres of ammonia gas could form? Assume all gases are at the same temperature and pressure.

Which is stronger: the covalent bond that holds atoms together within a molecule or the electrical attraction between two neighboring molecules? Explain.

Why is helium trapped in the earth's crust? If it's its trapped in the earth's crust how does it get into the air that we breathe?

How much thermal energy is in 100 grams of water at 0 degrees celsius

What is the molar ratio of Li to N2 in the given reaction? 6Li + N2 → 2Li3N

Particles of matter how have both potential and kinetic energy is that true or false?

Visible light waves are part of the blank Spectrum

Why does a soccer ball stop rolling in a soccer game which newton law shows that?

What is the name of the compound PbS2 • 4H2O?

Why doesn't gravity pull water all the way to the center of the Earth?