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Laboratory Techniques
Page 4
Questions (371)
If a student extracts first with NaOH then with NaHCO3, what will be the result?
5 answers
asked by
Anonymous
404 views
For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium
2 answers
asked by
Hannah
498 views
Why is unnecessary to measure precisely 25 ml of unknown acid into the beaker?
1 answer
asked by
Veronica
374 views
For Extraction using a separatory funnel, what is poured into the funnel first the solution that is to be extracted or the
2 answers
asked by
Jasmin
827 views
If you forget to add phenolphthalein solution to a vinegar solution(after adding NaOH solution), how might you salvage the
2 answers
asked by
Robert
959 views
why must not the condensed water drip into the flask?
4 answers
asked by
felaa
1,378 views
what could be possible answers to these two questions.....1 why determine the amount of solvent by difference and not by
2 answers
asked by
Davia
474 views
We did a lab separating out the components of a mixture. One of the lab questions is "The weight of naphthalene was obtained by
3 answers
asked by
Martha
1,159 views
organic chemistry lab and why is water the first choice for recrystallization when all factors are equal?
3 answers
asked by
sharon
417 views
A student dissolved 30 mg of a crude unknown in 2 ml of 95% ethanol at room temperature. After chilling in an ice bath and
3 answers
asked by
Anonymous
466 views
how would you make 300mL of toluene and hexane in a artion of 70:30 respectively?
i don't un derstand please help
1 answer
asked by
steph
363 views
How do I prepare 30% v/v ethanol from 95% ethanol?
Thanks.
4 answers
asked by
annie
587 views
why is it necessary to use previously boiled and cooled distilled water in the dilution of your unknown carbonate mixture?
can
2 answers
asked by
tan ni
822 views
extraction lab:
suppose that aqueous and organic (diethyl ether) layers were not mixed thouroughly predict the effect that this
2 answers
asked by
jay
503 views
during the preparation of the capsule stain, the slide used to spread the India ink/bacteria mixture is discarded in the
1 answer
asked by
Liana
489 views
when trying to purify aspirin, why would i have to add hot water to the crystals that are formed, and then recool the crystals?
2 answers
asked by
chrissy
543 views
I am doing a lab on finding the molecular mass of a volatile liquid.
I first need to find the volume of water in the test tube.
2 answers
asked by
Sarah
494 views
was hoping someone can help me check if these answers make sense for a silver copper alloy lab.
3. Why don’t you have to weigh
3 answers
asked by
Dina
735 views
why is the reaction mixture extracted with sodium bicarbonate?give an equation and explain its relevance.
3 answers
asked by
priyanka
1,835 views
he forensic technician at a crime scene has just prepared a luminol stock solution by adding 12.0 g of luminol into a total
4 answers
asked by
Anonymous
1,797 views
what is the purpose of a hot filtration? when is it necessary to preform one?
1 answer
asked by
wiki
302 views
if you were not told which solvent to use in the recrystallization experiment, how would you determine a suitable
3 answers
asked by
hana
743 views
So i had trouble finding the answers to these questions on a lab:
Background: If we were using a burret/flask instead of a
2 answers
asked by
Ellan
546 views
Describe how you would prepare 250.0 mL of a 0.500 M solution of NaCl by using apparatus found in a chemistry lab.
2 answers
asked by
kim
579 views
An aspirin tablet weighing 0.400 g has been analyzed and contains 68.2 % ASA (180.16 g/mol) by mass. A student dissolved
the
4 answers
asked by
Joanne
2,036 views
When performing vacuum filtration of a solid in an unknown solvent, is it necessary to go and find out the solvent composition,
4 answers
asked by
~christina~
1,276 views
I have a question about solvent evaporation. If I had an organic layer and an aqueous layer in an unknown mixture of liquids and
5 answers
asked by
~christina~
1,192 views
What is EDTA exactly and why do we use it in lab setting? I researched but having a little hard time understanding the concept.
2 answers
asked by
Matt
598 views
Sorry, I didn't see this.
<b>Actually you have only one mixture; it happens to have two components. There is a more or less
1 answer
asked by
~christina~
464 views
Follinwing this procedure:
1. Obtain a burette. Rinse it by pouring water through it. Add 15 ml of the HCl into the burette. Hold
3 answers
asked by
RED FIRE
577 views
Experiment - Recrystallization of a solid
Purpose in this experiment acetanilide will be recrystallized from water, which serves
4 answers
asked by
SARAH
806 views
we have to do this lab tomorrow. my teacher says that we have to "indirectly measure the radius" of a marble- he will only
7 answers
asked by
Lamen
400 views
I performed a TLC of plant pigments in my lab class with a solvent of petroleum ether/ acetone (7:3) and used a silica gel
2 answers
asked by
Veronica
678 views
<b>The only reason I asked about the balance is that most analytical balances in use in schools weigh to the nearest 0.1 mg
3 answers
asked by
~christina~
486 views
You have a green solution and you are trying to read the absorbance. However, when you use the spectrophotometer at 680mm, you
1 answer
asked by
Anonymous
376 views
a compound you have prepared is reported in the literature to have a pale yellow color. when the substance is dissolved in hot
1 answer
asked by
mekonen
501 views
why is it necessary to store AgNO3 solution in an amber bottle?
Why must volhard titration be carried out in strongly acidic
3 answers
asked by
anonymous
849 views
NaCl was used to rinse a condenser after distillation of 4-methylcyclohexene to remove unreacted phosphoric acid. Why is
1 answer
asked by
Bert
380 views
Imagine that your initial absorbable reading for “low salt” fraction was too high, so you diluted your sample 4 times. When
3 answers
asked by
Nadia
45 views
This is one of those titration labs, maybe you could answer it?
Why must a buret be rinsed with NaOH solution before it is filled
3 answers
asked by
Rogers
510 views
Methods and Materials:
The starting materials for this lab were: a crucible, breakfast cereal (Kix), bun cent burner, 100 mL
7 answers
asked by
Suzy
771 views
Is it advisable or not to leave a solution in drying agent for a few days?
~I did this ..since my chem lab instructor said to but
1 answer
asked by
~christina~
396 views
Aiieeee!
Todays lab...good grief. I was supposed to dissolve 0.3g of impure sulfanilamide in enough ethyl alchohol (95%) and me
7 answers
asked by
~christina~
611 views
In lab...last one ...where I had to go and heat these brass cartileges (I really don't think that's spelled correctly) and the
1 answer
asked by
~christina~
367 views
Basically what color is yellow when they say "Yellow"?
<b>The titrations I have done are light yellow when approaching the end
1 answer
asked by
DrBob222
847 views
For the lab of Determining the % of iron in an iron ore sample
The instructions were to: 1) Weigh out btw 0.3-0.4g of iron ore 2)
2 answers
asked by
christina
1,431 views
For a wine titration my results obtained were...
0.6402%, 0.5814%,& 0.6006% the I calculated was 0.04936 according to my text
1 answer
asked by
christina
1,106 views
In general when instructions are to let a solution cool to room temp would it be incorrect to put the bottle containing the
1 answer
asked by
christina
629 views
I have a problem with my tree core samples. After graining them with a Wig-L-Bug, we noticed that some of the plastic material
1 answer
asked by
Domingo Sancho
453 views
A student loaded a mixture, dissolved in 1cm3 of dichloromethane, CH2Cl2, onto a small flash chromatography column and then
1 answer
asked by
sue
546 views
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