The Earth's atmosphere is made up of approximately

__

% nitrogen.

A. 1

B. 21

C. 78

D. none of the above

A phase is a part of a system with what type of composition? gaseous liquid different uniform

1. What is true about the atom?

Why might someone write their postcode on a tv or computer using a pen with fluorescent ink that is not visible in normal light?

Which is of these nonmetals are more reactive - bromine or krypton? Explain.

Which type of wave has a wave perpedicular to the disturbance? A: Mechanical B: Transverse C: Longitude D: Surface

A specific, electrically neutral atom of boron has 5 protons, 5 electrons, and 6 neutrons. what is the mass number of this atom of boron? 6 5 11 16

When does hail happen?

For the reaction, calculate how many moles of the product form when 0.012 mol of O2 completely reacts. Assume that there is more than enough of the other reactant. 4Al (s) + 3O2 (g) →2Al2O3 (s) Express your answer using two significant figures.

Nuclei with too many or too few neutrons are?

Be sure to answer all parts. Enter the formula for potassium dihydrogen phosphate and determine its molecular (formula) mass.