Mass Relationships in Chemical Formulas  

Put the following chemical formulas into two categories Put the following chemical formulas into two categories. Be able to tell me why/how you separated them. C6H6, CH4, H2O, N2O4, C2H8, H2O2, NO2, CH  

A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance. An empirical formula shows the simplest whole-number ratio of the atoms in a substance. H2O molecular empirical H2O CH2O C6H12O6 O O3 NH2 N2H4 C2H5 C4H10 Butane

Write the empirical formulas for the following molecules: acetylene (C2H2), which is used in welding torches glucose (C6H12O6), a substance known as blood sugar nitrous oxide (N2O), a gas that is used as an anesthetic gas (“laughing gas”) and as an aerosol propellant for whipped creams.

Percent Composition and Empirical Formulas Steps: Percent to mass Mass to moles Divide by small Multiply ‘til whole **If you have a 100g sample, the percent composition is the same as the mass

Ascorbic acid (vitamin C) cures scurvy. It is composed of 40.92 percent carbon (C), 4.58 percent hydrogen (H), and 54.50 percent oxygen (O) by mass. Determine its empirical formula.

Molecular Formula Steps: Find empirical formula Determine the molar mass of the empirical formula Find multiplier (molar mass given/empirical molar mass) Multiply empirical formula subscripts by the multiplier

A sample of a compound contains 30. 46 percent nitrogen and 69 A sample of a compound contains 30.46 percent nitrogen and 69.54 percent oxygen by mass, as determined by a mass spectrometer. In a separate experiment, the molar mass of the compound is found to be between 90 g and 95 g. Determine the molecular formula and the accurate molar mass of the compound.

A compound composed of 40. 68% carbon, 5. 08% hydrogen and 54 A compound composed of 40.68% carbon, 5.08% hydrogen and 54.24% oxygen has a molar mass of 118.1 g/mol. Determine the empirical and molecular formula.

Combustion Analysis —technique used to determine elemental composition (empirical/molecular formula) of an organic compound by combusting (reacting with O2) it under conditions where the resulting products can be quantitatively analyzed. Example: Combust 11.5 g ethanol composed of: C, H, O Collect 22.0 g CO2 and 13.5 g H2O

Suppose a substance has been prepared that is composed of carbon, hydrogen and nitrogen. When 0.1156 g of this compound is reacted with oxygen, 0.1638 g of carbon dioxide and 0.1676 g of water are collected. The molar mass of the compound is 31.06 g/mol. Determine the formula of the compound.