Which is an example of a compound? sand, gold, water, iodine

S (Express your answer as an ion)

How many millions of years ago did the earliest marine reptiles evolve from land reptiles?

The ka of phosphoric acid, h3po4, is 7.6  10-3 at 25 °c. for the reaction h3po4 (aq) h2po4 - (aq) + h + (aq) ∆h° = - 14.2 kj/mol. what is the ka of h3po4 at 60 °c?

What are sig figs in chemistry.

Why do Beryllium and fluorine combine in a 1:2 ratio?

Liquids: A) must be contained to stay in one spot B) have a variable volume, but a fixed mass C) are usually more dense than solids and gases D) cannot be changed into gases

Given the following list from the activity series of metals (from most active to least active) K, Na, Al, Mn, Cr, Cd, Co, Pb, Hg which reaction would you NOT expect to occur? 1. Co²⁺ (aq) + Al (s) → Al³⁺ (aq) + Co (s) 2.

Chemical reactions that release energy A. will not occur. B. need catalysts to occur. C. will always explode. D. often occur spontaneously.

Which metal exist in liquid state and can be cut with knife?

Based on the ionization energies of the alkali metals, which alkali metal would you expect to undergo the least exothermic reaction with chlorine gas? Express your answer as a chemical symbol.