How do you calculate the percent by mass of an element in a compound?

What happens to the rate of reaction when you decrease the temperature of a chemical reaction?

2000 joules are required to heat 125 grams of an unknown substance from 10 c to 28 c. What is the specific heat of the substance?

Facts about the outer core

The ksp of pbbr2 is 6.60 * 10-6. what is the molar solubility of pbbr2 in 0.500 m kbr solution

Which of the following elements has two valence electrons? a. Sr b. Na c. Al d. B

For what reasons would modern scientists accept dalton's atomic theory but not the idea of an atom proposed by the greek philosophers?

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?