Which is a simple substance that cannot be broken down into any other substances?

Explain how it is possible that a problem with hormones and feedback led to Anna Garcia's untimely death.

Diamond is the hardest substance known while graphite is one of the softest. Both are made only of carbon atoms. What is the most likely reason why this is true? A. Both are bonded ionically. B. Both are bonded covalently. C.

What does a mole represent?

Which is true of any physical or chemical reaction? * ?

How did the development of the earliest idea about atoms differ from the later work of scientists? A. It was based on sound evidence. B. There were explanations for the idea. C. It was based on the thoughts of an early philosopher. D.

A population of crabs live on a light-colored sandy beach. In this environment there is a population of birds that eat the crabs. One year, there is a volcanic eruption near the beach and dark volcanic ash covers the beach.

It would take one light year to travel to the sun? True or false?

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.