<span>Helium = 1
Carbon = 8
Nitrogen = 8
Strontium = 52
Tellurium = 71
If you look on a periodic table, on each element there is a number on
the top left. This represents the number of protons in an atom. Protons
have a mass of 1 (in relative to Carbon-13)
If we take nitrogen-15 for example; The number 15 tells you that the
isotope has a mass of 15. Now if you look on the periodic table,
Nitrogen has a proton number of 7. Only protons and neutrons have a
mass, electrons are considered to be negligable. Therefore the number of
neutrons Nitrogen-15 contains is 15 - 7 = 8 </span>
Elements and compounds are both examples of pure substances. Compounds are substances that are made up of more than one type of atom. Elements are the simplest substances made up of only one type of atom. i hope that helps:)
Answer:
For instance equation C6H5C2H5 + O2 = C6H5OH + CO2 + H2O will not be balanced, but PhC2H5 + O2 = PhOH + CO2 + H2O will; Compound states [like (s) (aq) or (g)] are not required. If you do not know what products are enter reagents only and click 'Balance'. In many cases a complete equation will be suggested.
Explanation:
L
mol/dm³ is measure for molarity
