How many electrons are needed to completely fill the second level energy? The third? The fourth?

Which statements describe how globes represent Earth's surface? Check all that apply. They are created to scale. They model all or part of Earth's surface. They are spherical and three-dimensional. They represent surface features using symbols.

Give three exaples of passive transport

Which is the smallest particle into which a compound can be broken down and still remain the same compound? A. atom B. mixture C. element D. molecule

What happens when an acid reacts with a metal such as magnesium?

What are four factors that affect the rate of a chemical reaction

Which physical method can be used for obtaining a sample of salt from a small beaker of salt water? boiling freezing chromatography sorting

Science is a unique field of thought because it relies on to describe the world. •Observations and experim •Teachers and students •Books and writings •Scientists and statements

Hemoglobin, a protein in red blood cells, carries o2 from the lungs to the body's cells. iron (as ferrous ion, fe2+) makes up 0.33 mass % of hemoglobin. if the molar mass of hemoglobin is 6.8 Ã 104 g/mol, how many fe2 + ions are in one molecule?

What could you predict about a methane molecule that would most likely be made by using both the quantum model of the atom and John Dalton's model?

What is the molar mass of an unknown hydrocarbon whose density is measured to be 1.97 g/l at stp?