What organisms appeared on Earth First?

a). gastropods

b). horn corals

c). brachiopods

d). crinoids

The atomic weight of copper, CuCu, is listed as 63.546. Which of the following statements are untrue:Check all that apply. All the copper atoms have 29 protons in the nucleus. The number of electrons in the copper atoms is independent of atomic mass.

What element has 3 valance electrons and 4 energy levels

General properties of matter include all but which of the following. a. Mass b. Color c. Volume d. Denstiy

Waves interact with different surfaces in different ways. Waves often bounce off objects such as water. What is this form of wave movement called? A. refraction B. resonance C. reflection D. interference

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 20.4 g of carbon were burned in the presence of 66.2 g of oxygen, 11.8 g of oxygen remained unreacted. What mass of carbon dioxide was produced?

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.

Nuclei with too many or too few neutrons are?