What is a substance combination of different atoms?

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

Click the button that shows the correct relationship of the electron affinities of the elements sodium and phosphorus. sodium’s electron affinity value is more negative than the electron affinity value of phosphorus. phosphorus’ electron affinity value is more negative than the electron affinity value of sodium. this information cannot be determined using the periodic table. answer is b on e2020.

How does kepler second law of planetary motion overthrow one of the basic beliefs of classical astronomy