99℅ of HNO3 is? for 25 pts ...

Explain the relationship between a main-group element's lettered group number (the number of the element's column) and its valence electrons.

If all living systems, not plants, have blood; then why do blood types matter?

What mass of H₂O is formed when excess H₂ reacts with 64 g of O₂? * 2H2+O2 - ->2H2O Answer: 72g

True or False: The atomic masses of the elements are not whole values because of quarks.

Why do elements in the same group have similar properties

Altering the pressure of a system can affect the rate of a chemical reaction. true false

What does ice cream melt on a hot day which type of thermal energy transfer does this melting represents

For which purpose do biochemists insert human genes into bacteria? to find a cure for the common cold to produce insulin for diabetics to kill resistant strains of bacteria to evolve certain species of bacteria

Cracks in rocks chemical or mechanical

A large boulder falls from an underwater ledge and crashes on the floor of the ocean. A pod of dolphins is 800 meters away. Determine how long it takes for the sound of the crash to reach the dolphins. A) 0.5 sec B) 0.3 sec C) 2.3 sec D) 1.9 sec