# Search results

1. ### Help on empirical formula

Vitamin B5 is called niacin or nicotinic acid. Its percentage composition by mass is (58.4% Carbon) (4.09% Hydrogen) (25.99% Oxygen) and (11.38% Nitrogen). What is the empirical formula of vitamin B5?
2. ### Organic Compounds Structural Formula

when drawing the structural formula for 2-methylbutane or 2,3-dichloro-2-methylbutane,does it matter which end of the chain i begin counting from?
3. ### Period 3 ionization energy

i am stuck on this question and people are giving me different answers. Ok which period 3 element has the following succesive ionization energies: 1800,3000,3600,5800,13200
4. ### Succesive Ionization Energies

The succesive ionization energies in kj/mol of an element x found in period 3 of the periodic table are: 1800,3000,3600,5800,13200. With the aid of a periodic table,what is element x?
5. ### Electronic configuration

here is my problem. Galium Nitride is an Ionic Compound. Work out the electron arrangement of the Nitrogen ion
6. ### Concenctration of a mass

Hi guys,here is my question. What is the Concentration of Na2CO3 when it dissolves in a solution and forms a volume of 100 cubic cm? Concentration= moles/volume. I found moles using mass/atomic mass of Na2+C+03. Then i used moles/volume to calculate concentration. Correct?
7. ### Mole Concept

How many Gold atoms are in Gold mass of 2.5g? 15 percent of the mass is pure Gold. So first i found 15 percent of the mass which i used to calculate the number of moles. Then i multiplied the moles by Avogadros number to give me the atoms. Anyone help