How many protons does calcium have?

A volcano has erupted. What dangers are the neighboring towns at risk of?

Which of the following is made up of a coordinate covalent bond? A. sodium chloride (NaCl) B. ammonia (NH3) C. chlorine (Cl2) D. aluminium bromide (AlBr3) E. carbon monoxide (CO)

Draw the Lewis structure for 3 nitrogen-containing compounds.

Which is the most important question for deciding if a chemical reaction has occurred? Was there a change in the size? Was any heat energy given off? What is the density of the substance? What is the texture of the substance?

Energy cannot be created or destroyed. Does the statement describe a scientific law?

The definition of volume is? a) width*height b) the space occupied by mass c) the space occupied by a liquid d) the mass of liquid required to fill a container

What is the empirical formula of a substance that is 53.5% C, 15.5% H, 31.1% N?

What is the lowest layer of the atmosphere and what is its highest altitude?

An atom that has 84 protons and 86 neutrons undergoes a reaction. At the end of the reaction, it has 82 protons and 84 neutrons. What happened to the atom?

A compound of material formed by a chemical is known as?