Mole-Mass+and+Mole-Volume+Relationships

Objectives:
1. Use molar mass to convert between mass and moles of a substance

2. Use the mole to convert among measurements of mass, volume, and number of particles (kevin and HJ: i accidentally deleted your work from clicking "recover previous draft". heres a new one.)(Alex)

The mole is a measuring unit for the number of particles. each mole of any substance contains (6.02*10^23) paricles.

example problems:

how many moles of iron is (1.25*10^23) atoms of iron? (1.25*10^23)/(6.02*10^23)=(2.08*10^-1) mol Fe. explain: because 1 mole of any substance contains (6.02*10^23) number of particles, by putting (1.25*10^23) over (6.02*10^23) one would be able to obtain the number of moles of Fe of which (1.25*10^23) contains.

How many atoms are in 2.12 mol of O2? (2.12)(6.02*10^23)(2)= (2.55248*10^24) atoms explain: since each mole of O contains (6.02*10^23) and one O2 molecule contains 2 O's, one can find the # of atoms in 2.12 moles of O2 by using the above method.

3. Be able to properly use terminology such as: molar mass, standard temperature and pressure (STP), and molar volume (Alex) Molar mass - The molar mass of any substance is the mass (in grams) of one mole of the substance

Standard Temperature and pressure (STP) - As the volume of a gas varies with a change in temperature or a change in pressure, a volume of gas is usually measured at a standard temp. adn pressure (STP). the Standard temp. is 0 degrees C, the standard pressure is 101.3kPa, or 1 atm.

Molar volume - At STP, 1 mol of any gas occupies a volume of 22.4L. this quantity, 22.4L, is known as the molar volume of a gas and is measured at STP.

example problem

determine the vol., in L, of 0.7 mol SO2 gas at STP.

0.7mol*22.4L= 15.68L SO2

explain: because 1 mol of any gas at STP has a vol of 22.4L, 0.7mol would therefore be 0.7*22.4 L of gas.