Calculate molar mass
Add up the atomic masses of every atom in a formula, like glucose C₆H₁₂O₆, to get grams per mole.
The molar mass of a compound is the sum of the atomic mass of each atom, counting every atom in the formula. Glucose is C₆H₁₂O₆: 6 carbons, 12 hydrogens and 6 oxygens.
With C = 12.011, H = 1.008 and O = 15.999 (g/mol): 6 × 12.011 + 12 × 1.008 + 6 × 15.999 = 72.066 + 12.096 + 95.994 = 180.156 g/mol.
- The Chemistry toolkit (Subject toolkits in the Reference library) has a Molar mass tab. Type a formula such as C6H12O6 or Ca(OH)2 and it lists each element and the total.
- The same toolkit has a periodic table tab if you need an atomic mass.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type the carbon part, 6 × 12.011, then +.
6×12.011+Type the hydrogen part, 12 × 1.008, then +, and the oxygen part 6 × 15.999.
12×1.008+6×15.999Press enter.
enter
You should see180.156
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type 6 × 12.011 + 12 × 1.008 + 6 × 15.999 in one line.
6×12.011+12×1.008+6×15.999Press = . The result shows as a fraction at first, so press S⇔D to see the decimal.
=S⇔D
You should see180.156
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Carbon: 6 ENTER 12.011 × .
6ENTER12.011×Hydrogen: 12 ENTER 1.008 × then + adds it to the running total.
12ENTER1.008×+Oxygen: 6 ENTER 15.999 × then + .
6ENTER15.999×+
You should see180.1560
Tips
- A bracket multiplies everything inside: Ca(OH)₂ has 1 Ca, 2 O and 2 H.
- Use the atomic masses your course gives you, so that your answer matches the answer key.