<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>
<span>The following is the order from lowest boiling point to highest based on the types of forces these compounds have:
CO2
CH3Br
CH3OH
RbF
CO2 is a nonpolar molecular compound. The only intermolecular force present is a relatively weak dispersion force, because of the small molar mass. CO2 will have the lowest boiling point. ď‚· CH3Br is a polar molecule. Dispersion forces (present in all matter) and dipoleâ’dipole forces will be present. This compound has the next highest boiling point. ď‚· CH3OH is a polar molecule, which can form hydrogen bonds; these are especially strong dipole-dipole attractions. Dispersion forces and hydrogen bonding are present to give this substance the next highest boiling point. ď‚· RbF is an ionic compound. Ionâ’ion attractions are much stronger than any intermolecular force. RbF has the highest boiling point</span>
The mass in grams of nitric acid that is required to react with 454g C7H8 is 932.72 grams
calculation
find the moles of C7H8 used
moles = mass/molar mass
= 454 g/92 = 4.935 moles
balanced reacting equation
C7H8 +3 HNO3 = C7H5N3O6 +3 H20
by use of mole ratio between C7H8 to HNo3 which is 1:3 the moles of HNO3 =4.935 x3 = 14.805 moles
mass of HNo3 = moles x molar mass
= 14.805 x 63 = 932.72 grams
part B
the mass of C7H5N3o6 = 2045.5 grams
calculate the moles of C7H8
= 829 g/92 g/mol = 9.011 moles
by use of mole ratio between C7H8 to C7H5N3O6 which is 1:1 the moles of C7H5N3O6 is also = 9.011 moles
mass of C7H5N3O6 is therefore = moles x molar mass
=9.011 x227 = 2045.5 grams