Why doesn't the mass number of an isotope match the atomic mass given on the periodic table?

An unknown element is found to have three naturally occurring isotopes with atomic masses of 35.9675 (0.337%), 37.9627 (0.063%) and 39.9624 (99.600%).

Why is H-H considered non-polar?

What is the formula of the compound hydrogen gas?

One difference between mixtures and pure substances is that A) mixtures can be physically separated. B) mixtures are made of one type of atom. C) pure substances have no chemical bonds. D) pure substances can be physically separated.

When the metallic element sodium combines with the nonmetallic element bromine, br2 (l), how can you determine the chemical formula of the product? how do you know whether the product is a solid, liquid, or gas at room temperature?

How many particles are in 1 mole of a substance?

Initially you dissolved all, or most, of the p-aminobenzoic acid in ethanol. then you slowly added sulfuric acid. as you did this, a large amount of white solid formed. during the course of the reaction, that white solid dissolved.

How do you know if a chemical reaction has occurred?

Why must a container or system be closed for equilibrium to be established?

What is the bond angle between the hydrogen atoms in an ammonia (NH₃) molecule?