What is the total amount of matter in an ecosystem doing? always changing always increasing always decreasing remaining the same

Which pair of elements would you expect to exhibit the greatest similarity in their physical and chemical properties? Sr, Te Ga, As Rb, I N, P Ti, Ne

Hydrogen is a pure substance represented by the chemical symbol h. which of the following best describes hydrogen a. hydrogen is a compound made of only one kind of atom. b. hydrogen is a compound made of two or more kinds of atoms. c.

A student collected 10grams of hydrogen and 79.4 grams of oxygen. How much water was originally invloved?

If the value for q is + 450 J, what can you conclude about a process? A) it is endothermic and the temperature increased B) it is endothermic and the temperature decreased C) it is exothermic and the temperature increased D) it is exothermic and the

How many grams of O2 are in a 5.0 mol of the element? A. 16 g B. 80 g C. 160 g

What do all of the flexible objects have in common

If you convert 4.5 grams of water to moles you would have

In an atom of argon-40 the number of protons

What statements applies to the horizontal rows or periods in the periodic table?

What can scientists measure to provide evidence that electrons can move from one energy level to another?