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Determing Avogadro

Experiment 2: Avogadro and All That

Objective

  • To help you become familiar with the layout of the laboratory including safety aids and the equipment that you will be using this year.
  • To make an order-of-magnitude estimate of the size of a carbon atom and of the number of atoms in a mole of carbon, based on simple assumptions about the spreading of a thin film of stearic acid on a water surface

Grading

  • Lab Report (90%)
  • TA points (10%)

Before coming to Lab

Read the following:

  • Lab instructions
  • Background Information
  • Concepts of the experiment

Print out the lab instructions and report form.

Read and sign the equipment responsibility form and the safety rules. Email Ms. Duval, at nduval@rice.edu , to confirm completing this requirement by noon on September 14 th size 12{ {} rSup { size 8{"th"} } } {} .

Introduction

Since chemistry is an empirical (experimental) quantitative science, most of the experiments you will do involve measurement. Over the two semesters, you will measure many different types of quantities – temperature, pH, absorbance, etc. – but the most common quantity you will measure will be the amount of a substance. The amount may be measured by (1) weight or mass (grams), (2) volume (milliliters or liters), or (3) determining the number of moles. In this experiment we will review the methods of measuring mass and volume and the calculations whereby number of moles are determined.

Experimental Procedure

1. Identification of Apparatus

On the tray (in DBH 214) we have a number of different pieces of common equipment. We will, identify and sketch each - I know this may sound a trivial exercise but it is necessary so that we are all on the same page.

  1. beaker
  2. Erlenmeyer flask (conical flask)
  3. side-arm Erlenmeyer flask
  4. graduated (measuring) cylinder
  5. pipettes, both types graduated and bulb
  6. burette
  7. Bunsen burner
  8. test tubes
  9. watch glass
  10. volumetric flask

2. Balance Use

In these general chemistry laboratories, we only use electronic balances – saving you a lot of time. However, it is important that you become adept at using them.

Three aspects of a balance are important:

  1. The on/off switch. This is either on the front of the balance or on the back.
  2. The "Zero" or "Tare" button. This resets the reading to zero.
  3. CLEANLINESS . Before and after using a balance, ensure that the entire assembly is spotless. Dirt on the weighing pan can cause erroneous measurements, and chemicals inside the machine can damage it.

Balance Measurements :

  1. Turn the balance on.
  2. After the display reads zero, place a piece of weighing paper on the pan.
  3. Read and record the mass. (2)
  4. With a spatula, weigh approximately 0.2 g of a solid, common salt NaCl. The excess salt is discarded, since returning it may contaminate the rest of the salt.
  5. Record the mass (1). To determine how much solid you actually have, simply subtract the mass of the weighing paper (2) from the mass of the weighing paper and solid (1). Record this mass (3). You have just determined the mass of an "unknown amount of solid."
  6. Now place another piece of weighing paper on the balance and press the Zero or Tare button then weigh out approximately 0.2 g of the salt (4). Thus, the zero/tare button eliminates the need for subtraction.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Gen chem lab. OpenStax CNX. Oct 12, 2009 Download for free at http://cnx.org/content/col10452/1.51
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