Scientists have hypothesized that oxygen began to build up in the Earth's atmosphere after the development of living things with the ability to

a. breathe air.

b. form tissues.

c. photosynthesize.

d. reproduce sexually.

What mass of ammonia will exert the same pressure as 12.8 mg of hydrogen sulfide (H2S) in the same container under the same conditions?

What mass of phosphoric acid (h3po4, 98.0 g/mol) is produced from the reaction of 10.0 g of p4o10 (284 g/mol) with excess water?

why polychromatic light gives continious spectrum if passes throught prism and why polychromatic light gives line spectrum when passes throught hydrogen gas what is the reason of different situation that forming continious and line spectrum

What is a property of a combustion reaction? A. Oxygen gas, O2, is a reactant. B. The products are simpler than the reactants. C. The reactants are simpler than the products. D. An uncombined element is on the reactant and product side.

Elements have a series of ionization energies for removing the first and additional electrons from the atom. Each ionization energy increases for successive electrons being removed.

A student places three ice cubes in a beaker and allows them to partially melt. if she measures the temperature of the water in the beaker, what will she most likely observe? explain your answer.

What is the metric unit for density

Is the compound CO ionic or covalent

What is the volume in ml of one pound of mercury?

How does the number of molecules in one mole of carbon dioxide compare with the number of molecules in one mole of water? A. There are four times as many molecules in one mole of carbon dioxide as there are in one mole of water. B.