Introductory Courses

What burdens does China's increasing energy use put on the environment?

What burdens does China's increasing energy use put on the environment?

What burdens does China's increasing energy use put on the environment?

FezOne2   657   4 Replies

maggie L.

Mealworm Behavior virtual lab

Mealworm Behavior virtual lab

If anyone has done the Mcgraw-Hill Mealworm Behavior virtual lab please help!!

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I have the answers for #1 and 2

3.   List one instinctive human behavior and on

rje   14195   2 Replies

duddy

How to grow a Douglas-Fir tree?

How to grow a Douglas-Fir tree?

I'm trying to grow one without buying a sapling.

How would I grow one from seeds? How about from cuttings? What season?

I've looked around and it's surprisingly hard to find good information on this.

FF.SMITH   936   1 Reply

nite_n_day

What are the problems of air pollution?

What are the problems of air pollution?

What are the problems in air pollution? (Relate to vehicles)

jtrof   444   1 Reply

nite_n_day

How does air pollution change the natural balance in the ecosystem (carbon, water, and nitrogen cycles)???HELP

How does air pollution change the natural balance in the ecosystem (carbon, water, and nitrogen cycles)???HELP

How does air pollution change the natural balance in the ecosystem (carbon, water, and nitrogen cycles)???HELP

#8   826   1 Reply

_vibram_

How low ratio A260/230 can effect ligation and how can I increase it?

How low ratio A260/230 can effect ligation and how can I increase it?

probably I should add that these DNA samples were gel extracted using column, so there is absolutely impossible that they are protein contaminated...

0103325   475   1 Reply

buk280forlife

Why is it necessary to use Cold Reagents in DNA extraction? How can you confirm something extracted is DNA?

Why is it necessary to use Cold Reagents in DNA extraction? How can you confirm something extracted is DNA?

We extracted DNA from a Pea by blending it, then mixing the resulting mushy thing with pineapple juice and alcohol. Some mucus-like substance floated. How can I confirm it is DNA? Also, why use cold pineapple juice?

rikantank   428   3 Replies

jtong

What is gram posetive and gram negative bacteria?

What is gram posetive and gram negative bacteria?

What is gram posetive and gram negative bacteria?

feven   352   1 Reply

jtrieu2

What is the composition of Cresyl Violet or Nissl Stain. Which intracellular biochemicals does it stain?

What is the composition of Cresyl Violet or Nissl Stain. Which intracellular biochemicals does it stain?

What is the composition of Cresyl Violet or Nissl Stain. Which intracellular biochemicals does it stain?

jtw0019   940   1 Reply

01blu_gsr

Writing a lab report

Writing a lab report

Hi
 I'm starting University in September , and I was just wondering are there any trusted web sites that write lab reports for every student needs in science for a reasonable fee?
I found a lot of fliers on campus offering this type of

Rockangel   1064   1 Reply

savio

Need help for Exercise 11 Activity 4

Need help for Exercise 11 Activity 4

 really need help with these!!!! Please!  Huh?

 Hemoglobin Determination
1. Is the male with polycythemia (sample 4) deficient in hemoglobin? Why? ___No because it was above the normal range. ___________________ ________________

us-tnguyen   2765   4 Replies

doseofmegan

SDS-PAGE vs. 2D Electrophoresis

SDS-PAGE vs. 2D Electrophoresis

I need to perform electrophoresis on the protein pellet obtained from a bacterial culture; I believe 2D electrophoresis would be best however the apparatus to perform this is not available. Do you think SDS-PAGE would be suitable or will the high qua

micro   1036   2 Replies

micro

2D-Electrophoresis Apparatus

2D-Electrophoresis Apparatus

What apparatus / materials are required to perform 2-D electrophoresis other than IPG strips and the chamber?

micro   827   1 Reply

colleen

what is the process involved to identify an unknown microbe?

what is the process involved to identify an unknown microbe?

how do i identify my unknown microbe if only one of my cultures is growing?

lilian   1496   1 Reply

savio

Staining

Staining

hello.
sometimes acid-fast bacteria accept the spore stain and spores accept the acid-fast stain. why?

MohammadP   1199   1 Reply

duddy

Buret readings in lab?

Buret readings in lab?

A dirty buret reading was used for an analysis causing droplets of HCl solution to cling to the buret wall. If HCl droplets cling to the buret wall between the initial and the final buret readings for an analysis, will the molar solubility of Ca(OH)2

DarkTakeda   1252   1 Reply

__Aycee

I do not understand the logic of this biology lab! help!?

I do not understand the logic of this biology lab! help!?

ok, well here's what the calculations instructions are telling me:

Calculate the base line using the data for this lab by subtracting the initial burette reading  (Vi) from the final burette reading (Vf)

my Vf is 44.9 ml and my Vi is 50.0 mL

so my

darkraven2728   380   1 Reply

leeo2014

Chemistry lab question, please help?

Chemistry lab question, please help?

A student titrated the assigned unknown with a volume of 1.54 mL of 0.1000M HCl, using 25.00 mL of the unknown.  Would you consider this a relatively good result?  Explain why or why not?   If not explain how one would change the conditions of the ex

Ikkou   424   1 Reply

rinaann

Calculate the mole percent oxygen in the air Lab?

Calculate the mole percent oxygen in the air Lab?

In my chem class we are doing a lab where we must find the mole percent oxygen in air saturated with water vapor and air from which the water vapor has been removed.

First of all, what exactly is mole percent oxygen?
Secondly, If we have the initial

smiley13   632   1 Reply

darkwind

Why did my experiment kept going wrong? Titration with NaOH

Why did my experiment kept going wrong? Titration with NaOH

so i added say about 1.025 g of KHP to my flask and about 35 mL of water.
i filled up my buret to 0.00 ml of NaOH.
placed flask under buret with 3 drops of pendol.... (it has a long name lol) in the flask
now when i was doing the titration the naoh i

Rinab123   453   2 Replies

smiley

what are the laboratory tools and its uses.?

what are the laboratory tools and its uses.?

pls give all of the tools

smiley77   408   2 Replies

Nurnin

What is Good Laboratory Practice?

What is Good Laboratory Practice?

What is Good Laboratory Practice?

o2226500   414   1 Reply

Rimfrost

Chemistry Lab Final...Acid/Base pKa Calculation....Please Help!?

Chemistry Lab Final...Acid/Base pKa Calculation....Please Help!?

My chemistry lab final is asking us to calculate the molecular mass as well as the pKa values of an unknown monoprotic acid.  We ran a total of 4 titration trials which allowed us to complete the following calculations: Mass of Sample, Initial and Fi

ikilledpablo   436   1 Reply

rimrod75

Titration Lab errors...please help?!?!? it's urgent!!?

Titration Lab errors...please help?!?!? it's urgent!!?

hey
anyways my classmates and i conducted a titration lab this past friday....i really can't tell you what specifically the acid and base were, but all i know it that the acid contained 2 drops of phenolphthalein, and had a magnetic stir in it (th

o2blea   454   2 Replies

nurkasih

Please help!!!!!!!! How do I calculate the concentration of Cl- in g/L in a sample solution?

Please help!!!!!!!! How do I calculate the concentration of Cl- in g/L in a sample solution?

We determined the chloride content of a solution with Mohr's method of titration.
1) We were asked to calculate the concentration of Cl- in our sample solutions in mol/L and g/L in our lab report.
conc of AgNO3 is 0.05M, titre volume used is 16.38mL

jtwalls   432   1 Reply

tonyagodsey

Chemistry Lab Help Again!!!?

Chemistry Lab Help Again!!!?

My chemistry lab final is asking us to calculate the molecular mass as well as the pKa values of an unknown monoprotic acid. We ran a total of 4 titration trials which allowed us to complete the following calculations: Mass of Sample, Initial and Fin

Ikkou   393   2 Replies

JUAN99

Titration lab questions?

Titration lab questions?

I did an experiment in which I titrated vinegar by putting 2ml of vinegar into an erlenmeyer flask then adding approximately 25ml of distilled water and 4 drops of phenolphalein to the flask and then swirling it. I titrated the vinegar by adding fixe

nzegbuna.ify   336   1 Reply

leenamu

I need some help on this chemistry lab, please?

I need some help on this chemistry lab, please?

I obtained a calorimeter and added 10mLs of 6.00M sulfuric acid.  I  obtained a burette and added 50mLs of 6.00M sodium hydroxide.  I collected the  pH meter and titration data (This lab was done on the computer).  I Started the titration by adding N

rimrod75   337   1 Reply

jtwalls

Titration Help! (chemistry)?

Titration Help! (chemistry)?

I am working on calculations for a lab where we standardized NaOH and HCl solutions with titrations.

For the NaOH, I have the mass of KHP (the acid used) and the volume of the NaOH used to titrate to the equivalence point. How can I figure out what

FF/EMT   654   5 Replies

o2blea

Finding the unknown concentration of a CH3COOH (acetic acid)

Finding the unknown concentration of a CH3COOH (acetic acid)

we're doing a lab about acid-base titrations..
we're gonna use NaOH as our standard solution to find the unknown concentration of a CH3COOH (acetic acid) solution.

the problem is, we're given with vinegar as our solution..which is 5% acetic acid by

zuckalemon   719   2 Replies

NURGirl

Titration of HCl?

Titration of HCl?

The lab I just did was determining the concentration of a random HCl solution with a .11 M NaOH solution. Afterwards are a series of questions based on what could happen if you messed up somewhere.  These are the ones I can't figure out/unsure of.

D

Ikkou   456   1 Reply

darkspirt

degree of uncertainties?

degree of uncertainties?

which of the following has the highest degree of uncertainty in measurment?
A)Burette
B)Beaker
C)Pipette
D)Measuring Cylinder

smiley13   417   1 Reply

ff151djg

standardization of HCl by borax?

standardization of HCl by borax?

discussion about standardization of HCl by borax for lab report

nuria   1919   1 Reply

tom_andrews

What is used as a support for crucibles and funnels?

What is used as a support for crucibles and funnels?

what is used as a support for crucibles and funnels?

what is used to measure mass?

what is used to heat or hold a solution?

what is used for titration labs?

rillameister   433   1 Reply

FF.SMITH

difference b/w iodometric n iodimetric reactions??anyone!?

difference b/w iodometric n iodimetric reactions??anyone!?

my teacher hinted it has something to do with the starch test. iodine (tincture iodine the end product),its a subject of class 10 lab preparations......inorganic chemistry chemical equilibrium ...pls help spot the difference .

__Aycee   337   1 Reply

tonyagodsey

titration question? chemistry?

titration question? chemistry?

how is a titration performed and why?
i missed the titration lab and i'm so confused.

ff.marquis   420   1 Reply

smiley14

Chemistry help pleaseeeeee ?

Chemistry help pleaseeeeee ?

deionized water from a wash bottle was added to wash down the wall of the receiving flask during the titration. how does this affect the reported molar concentration of the saturated Na2s2o3 solution thiosulfate solution ?

The bleach is diluted but

Nurs-4   348   2 Replies

zues1000

TITRATION HELP, lab report!?

TITRATION HELP, lab report!?

Im writing a lab report and im stuck on how to present my results and findings ? anyone experienced in this and could give me any tips ? I have done a table with the initial burette reading, final burette reading and the volume of acid used. Im stuck

tomtom1   329   1 Reply

leemons

Find concentration of NaOH solution (lab problem)?

Find concentration of NaOH solution (lab problem)?

A 5.00-g sample of the monoprotic acid KHP (molar mass=261 g) is titrated with an unknown solution of NaOH. The endpoint of the titration is reacher after adding 55.0 ml of NaOH. Find the concentration of the NaOH solution. Also, if possible, suggest

TonyaJ98   366   1 Reply

leelo

Titration lab calculations help please?

Titration lab calculations help please?

Ok so im super confused on how to do these calculations. we need to do something called error propagation. I understand somewhat how to do the calcuations without the error but with the error im confused.

Trial 1 - initial volume = 11.41mL, final v

nzp123   373   1 Reply

o2982794@rtrt