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CHM 1025L Mole Concept 1

 Name:_____________________________________________________

Lab Partner’s Name:_____________________________________________________  

Date:___________________________

Laboratory: The Mole

Text reference: Hein and Arena, ch. 7

Introduction: One mole of anything contains 6.022 x 1023

 parts. If you have onemole of sodium, Na, an elemental substance, you have 6.022 x 10

23 atoms of Na. If you

have one mole of carbon dioxide, CO2, you have 6.022 x 1023

 molecules of CO2 whichcontains 2 moles of O atoms and 1 mole of C atoms.

In this laboratory exercise, you will obtain the masses of selectedsolid substances or the mass or volume of selected liquids. Using this information as well

as other information given, you will do calculations that pertain to moles, molecules, andatoms. Molar mass of a substance can be calculated by adding the molar masses of the

individual elements that are present in the compound from the formula. Alternatively, ifthe formula (or in the case of an elemental substance, the symbol) is not known the molar

mass can be determined by dividing the mass of the substance by the number of moles ofthe substance. (Remember that the unit of molar mass is g/mol.)

mass of substance (g) moles of substance # molecules # atoms

To convert from: a. mass to moles or moles to mass, use molar mass b. moles to molecules or molecules to moles, use Avogadro’s

number. If the substance is atomic, you will convert toatoms directly, using Avogadro’s number. 

c. to convert to number of atoms (of a molecular substance),count the number of atoms in each molecule of the

substance and multiply by that number.

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CHM 1025L Mole Concept 2

Part 1. Solids.  Obtain the mass of each of the solids. Note and deduct the massesof the flasks, which is written on the labels (includes the masses of the stopper and label.)

Show all calculation set-ups on the next page. Answers without supporting calculationswill be given zero credit. After determining the molar mass of Element A, identify it by

matching it to an elemental substance on the periodic table. Be sure to fill in all blanks

with the required information. Units should be on all data and answers need to contain thecorrect number of significant figures.

Flask A Flask B Flask C

Name cupric sulfatepentahydrate  _____________ _____________

(identify)

Formula  CuSO4  5 H2O K 2Cr2O7  _____________

or Symbol (identify) 

Total Mass  ____________ ____________ ____________

Mass of Flask   ____________ ____________ ____________

Mass of Substance  ____________ ____________ ____________

Moles of Substance  ____________ ____________ 1.25 mol

Molar Mass  ____________ ____________ ____________

(from formula) (from formula) (calculate)

# Molecules  ____________ ____________ N/A

# Atoms  ____________ ____________ ____________

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CHM 1025L Mole Concept 3

Calculations for Solids, Part 1 : show all set-ups for each calculation.

Flask A

Flask B

Flask C

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CHM 1025L Mole Concept 4

Part 2 Pure liquids. For this part, you will need to obtain either the mass or the volumeof the liquid as noted, then, determine the other using density. Note and deduct the

masses of the cylinders, which is written on the labels (includes the masses of the stopperand label.) Show all calculation set-ups on the next page. Answers without supporting

calculations will be given zero credit. Units should be on all data and answers need to

contain the correct number of significant figures.

Substance Cylinder C Cylinder D Cylinder E

Name  Trichloroethane Acetone Unknown 

Formula CH3CCl3  CH3COCH3  N/A

Total Mass  N/A  ____________ ____________

Mass of Cylinder  N/A  ____________ ____________

Mass of Substance  ____________ ____________ ____________

(calculate)

Volume of Sub.  ____________ ____________ ____________

(read) (calculate) (calculate)

Density of Sub. 1.349 g/mL  0.7908 g/mL  0.9982 g/mL 

Moles of Substance  ____________ ____________ 1.75 mol

Molar Mass  ____________ ____________ ____________

(from formula) (from formula)

# Molecules  ____________ ____________ ___________

# Atoms  ____________ ____________ unknown

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CHM 1025L Mole Concept 5

Calculations for Pure Liquids, Part 2.

Cylinder C

Cylinder D

Cylinder E