# Stoichiometry CHEMISTRY A

Stoichiometry

CHEMISTRY A

Stoichiometry
can be thought of as the math of chemistry. It involves using relationships
between reactants and/or products to determine such quantities as mass, moles,
and number of atoms. Dimensional analysis is a way to simplify stoichiometric
problem solving. In this activity, you will use dimensional analysis in
order to count the number of atoms in a given substance.

1. A sample of
gold (Au) has a mass of 35.12 g.

a. Calculate the number of moles of gold (Au) in the sample and record in
Table 1. Show your work.

35.12au
x (1mol/197g)=.18mol

b. Calculate the number of atoms of gold (Au) in the sample and record
in Table 1. Show your work.

.18mol
x (6.022 x10^23 atoms/1 mol)= 1.08 x 10^23 atoms.

2. A sample of table sugar (sucrose, C12H22O11) has a
mass of 1.202 g.

a. Calculate the number of moles of C12H22O11 contained in the sample
and record in Table 1. Show your work.

1.202g
(1mol sucrose)/(342g)=3.5 x 10^-3 mol sucrose.

b. Calculate the moles of each element in C12H22O11 and record in Table
1. Show your work.

.00296

c. Calculate the number of atoms of each type in C12H22O11 and record in
Table 1. Show your work.

C= 7.2/3 x 10^22

H= 1.32 x 10^23

O= 6.62 x 10^22

 Table 1 Au C12H22O11 Mass (grams) 35.12 g. Molar mass (g/mol) .18mol Moles of each element .00296 C: H: O: Atoms of each element C: H: O:

Check answers and fill in chart