# ~christina~

Most popular questions and responses by ~christina~
1. ## graphing

Q: How could the function y=3t^2 +4 be plotted on a cartesian graph to produce a straight line? What would be the numerical values of the slope and the intercept of the line? For this it's explained in the lab book for physics as if the function is y=mx+b

2. ## Physics (When will Kathy overtake Stan if )

Kathy has a sports car that can accelerate at the rate of 4.90m/s^2. She races with Stan. Both cars start from rest but experienced Stan leaves starting line 1.00s before her. Stan moves with a constant aceleration of 3.90m/s^2 and Kathy maintains an

3. ## science(chem)

I synthesized Nylon in my lab for organic chem. I need help figuring out the theoretical yield so I can compare it to my product that I synthesized. I looked up the reaction online on Google by typing in "Synthesis of adipoyl chloride and nylon 6.6." I

4. ## science

A major motor company displays a die-cast model of its first automobile, made from 9.35kg of iron. To celebrate its one-hundreth year in business, a worker will recast the model in gold from the original dies. What mass of gold is needed to make the new

5. ## Physics but could be just Math ?????

A creature moves at a speed of 5.00 furlongs per fortnight (not a very common unit of speed). Given that 1 furlong= 220 yards and 1 fortnight= 14 days determine the speed of the creature in m/s. ~ for this question: know: 5 furlongs/ fortnight 1fortnight=

6. ## science

Do experimental measurements give the true value of a physical quantity? explain. ~I say no it doesn't. But why that is is up to debate on my part. I think that it doesn't give the true value because there is always a source of error and also varying

7. ## Physics => speed of sound variation

The speed of sound in air (m/s) depends on temperature according to aprox expression of v= 331.5 + 0.607 Tc Tc= temp in celcius In dry air, temperature decreases about 1deg celcius for every 150m rise in altitude. a) assume the change is constant up to

8. ## Significant figures

How would I go and express these numbers with 3 significant figures in normal notation? a)15.08 b)1444 c)83,909 d)0.524 e)0.0254 for d and e aren't they already with 3 significant figures and also in normal notation? for a, b, and c I can't figure out what

9. ## science (chem)

What would the best way to determine the organic layer from the aqueous layer in a extraction procedure? ~would it be to add a few drops of water to each layer and see what happens? or is there a better way since this procedure of adding a few drops of

10. ## Physics

A person can lift 45 kg ( aprox 100lb). Using specific gravity as 10.17 How many cubic meters of the metal could the person lift in a) air ? b) water ? c) in water ? Thanks

11. ## physics => really need help on 2 problems (#1)

A house has well insulated walls. It contains a vol of 100m^3 of air at 300K a) calculate the E required to increase the T of the diatomic gas by 1.00C b) If this E could be used to lift an object of mass m through a height of 2.00m what is the mass of m?

12. ## physics

The periods of oscillaton were measured down to 0.38s. How could this be done with common laboratory timers? -a given hint is : are the times exact values? I don't know how this would work b/c I've never heard of a timer or stopwatch thant can register a

13. ## Physics, Calculus(alot of stuff together)= HELP!!

A rod extending between x=0 and x= 14.0cm has a uniform cross- sectional area A= 9.00cm^2. It is made from a continuously changing alloy of metals so that along it's length it's density changes steadily from 2.70g/cm^3 to 19.3g/cm^3. a) Identify the

14. ## science(chem)

How would I make a 5% solution of sodium bisulfite? sodium bisulfite: NaHSO3 Molar mass: 104.06 g/mol is it 5% w/w or v/v or w/v b/c if it was w/w then it would be weight percent w/w= weight solute/ weight solution* 100 I need help on this Thanks

15. ## sand bath (chem)

what are disadvantages and advantages of using a sand bath to heat something in chem?

16. ## science (physics) Need to solve this today please

(a) Express the vectors A, B, and C in the figure below in terms of unit vectors. (b) Use unit vector notation to find the vectors R = A + B + C and S = C – A – B. (c) What are the magnitude and directions of vectors R and S? Well the picture goes and

17. ## chem

I had to go and do a oxidation- reduction lab where: I went oxidized borneol with sodium chloride and added 0.360g racemic borneol, 1ml acetone, and .30ml glacial acetic acid. Then I heated and added through the condenser every 4 minutes .5ml 6% sodium

18. ## science(chem)

The pKa of HEPES is 7.55 at 20C and it's MW is 238.31. Calculate the amounts of HEPES in grams and of 1.0M NaOH in ml that would be needed to make 300ml of 0.2M HEPES buffer at 7.2. I'm not sure how to go about doing this problem. Help please.

19. ## science(chem)

I did a dehydration rxn with 1.424g of 4-methylcyclohexanol with .40ml 85% H3PO4 and 6 drops of concentrated H2SO4. I have to calculate the limiting reagent even though I do suspect it to be the 4-methylcyclohexanol. I do know the ratio is 1mol H3PO4: 3mol

20. ## science(chem)

Solubility: Solubility of compounds in a)water (highly polar) b)methyl alchohol (intermediate polarity) c)Hexane (nonpolar) My guess 1. Benzophenone a) not soluble b) partially soluble c) soluble 2. Malonic acid a) soluble (since it's polar) b) soluble c)

21. ## Physics - drwls can you help me with this?

A 2.00kg block hangs from a rubber cord, being supported so that the cord is not stretched. The unstretched length of the cord is 0.500m and it's mass is 5.00g.The "spring constant" for the cord is 100N/m. Block is released and stops at lowest point. a)

22. ## Physics

Speedy Sue during is driving at 30.0m/s and enters a 1 lane tunnel. She then observes a slow moving van 155m ahead traveling at 5.0m/s. She applies the brakes but can only accelerate at -2.0m/s^2 b/c road is wet. a) will there be a collision? How do you

23. ## science(chem) Dr.Bob-> need help on this long lab

For 1 part of the lab I: prepare 4-Bromo-2-chloro-6-iodoaniline I dissolve 250mg recrystallized 4- Bromo-2-chloro-6-iodoaniline in 4ml of glacial acetic acid in 25ml erlenmyer flask and add 1ml water to the mixture. Then I prepare a solution of 250mg

24. ## Extraction

Lab..again 0.050g benzoic acid/succinic acid/sodium benzoate. -choose 1 and put 0.050g of that compound into 5ml conical vial -add 2ml methylene chloride and 2ml water -cap vial and shake until all solid is dissolved. -let solution sit until 2 layers are

25. ## Physics..an electric field

4 charged particles are at the cornedrs of a square of side a as shown. a) determine the magnitude and direction of the electric field at the location of charge q b) what is the total electric force exerted on q? basically picture is like this below It's a

26. ## American Lit => Ms.Sue (Poetry analysis help)

Poem "for rosa parks" And how was this soft-voiced woman to know that this was "No" in answer to the command to rise would signal the begining of the time of walking Soft the word like the closing of some aweful book, a too-long story with no pauses for

27. ## Plastic Moulds ==> Couldn't find anything myself

I'm proposed a way I'd synthesize plastic...polyethylene to shape into a pipe PROBLEM: not sure how or what I would use to make a mold or best method to produce a PIPE not sure what a mold should look like to produce a hollow object like a pipe. OR what

28. ## Science(chem)

This question relates to what someone posted below... It was explained to them that a reducing agent is oxidized when it reduces? I would like to get this concept straightened out in my head. I originally got this concept when I did gen chem but I have

29. ## citation of UNEP PDF online assessment/report

How would I cite a document from the UNEP website? (PDF document) APA style? I've been looking but it looks like you have to cite it a special way? Is this true? I cannot personally find the, "session" or etc. It is a document evaluating the environment,

30. ## Forced Oscillation - drwls => I need your help =)

A 2.00kg object attatched to a spring moves without friction and is driven by an external force given by F= (3.00N)sin(2pi*t) The force constant of the spring is 20N/m. Determine a) period b) amplitude of motion a)T= 2pi/omega T= 2pi/ 2pi= 1s b)A= (Fo/m)/

31. ## Dr.Bob (about finding the ml of ethanol)

~From before since the question's been bumped to the next page. Just copied and paste with added stuff. I'm confused as to what to do for the calculations for my lab. Lab: Semimicroscale crystalization-erylenmyeyerflask and Hirsch Funnel Weigh 0.30g of

32. ## science(chem)

Concerning TLC plates... 1. why should't I allow the solvent to reach the top of the plate? (I assume it's the same as using paper like I did in gen chem but I'm not sure I know why it shouldn't be allowed to reach the top... what would happen?) 2. why

33. ## science(chem)

I was told before that it takes 2 mol of fluorene to be reduced by 1mol of sodium borohydride.... How many mg of fluorenone can 0.53 mol of sodium borohydride(NaBH4) reduce? what I got... 0.53mol NaBH4 ( 2mol fluorenone/ 1mol NaBH4)(180.192g/1mol

34. ## Science ?

I was making some instant coffee and it had clumped up...I was heating up some water to go and make coffee... Then I just looked in the container and started to shake the container with the lid off a bit..that is when I knoticed the larger clumps of

35. ## science(chem)

Can someone tell me if this objective for my lab report sounds alright? The objective of this multistep lab was to ultimately synthesize 4-bromo-2-chloro-6-iodoaniline through the intermediate formation of acetanilide, 4-bromoacetanilide,

36. ## science (chem) Rf values

consider a sample that is a mixture of biphenyl, benzoic acid, and benzyl alchohol. The sample is spotted on a TLC plate and developed in a methylene chloride cyclohexane mixture. Predict the relative Rf values for the three components in the sample. For

37. ## Fluorenol (In the Merck Index or anywhere else)

what is this? (Fluorenol) I can't find it in th Merck Index or online... I'm going to be using it in organic chem and I can't find the info to use in my chemical table.. Is it a combination of fluorene and alchohol? I just looked up fluorene and it said

38. ## Physics (forgot to post this question #2)

During the compression stroke of a certain gasoline engine, the pressure increases from 1.00atm to 20.0atm. If the process is adiabatic and the fuel air mixture behaves a a diatomic ideal gas a) by what factor does the volume change b) by what factor does

39. ## Graphing interpretation

What would it mean if the line of a linear regression graph went through the origin? If it doesn't go through the origin and I make it go through the origin, what am I doing? I was looking for the answer to this and all I came up with was that if the line

40. ## science(chem) Dr.Bob Question from before

I'm doing an experiment and I'm supposed to have neutral basic and acid samples of solution. I just wanted to make sure that I knew which was which. (If I'm incorrect, please correct me) Acid: 0.7ml 10% H2SO4 + 0.7ml 10% Na2WO4(sodium tungstate) Basic:

41. ## Physics... Coulomb's law

Two small silver spheres with a mass of 10.0g, are separated by 1.00m. Calcuate the fraction of the electrons in one sphere that must be transfered to the other to produce an attractive force of 1.00x10^4 N (about 1 ton) between spheres (number of

42. ## Dr.Bob the question Ihad reposted (NOT the old one

Yes...another calculation problem. Rxn: 1ml isopentyl alcohol + 1.5ml glacial acetic acid + 3 drops sulfuric acid=> isopentyl acetate to calculate the theoretical yield.. I know that the acetic acid is in excess but how would I calculate the theoretical

43. ## science(chem)

I'm confused as to what to do for the calculations for my lab. Lab: Semimicroscale crystalization-erylenmyeyerflask and Hirsch Funnel Weigh 0.30g of impure sulfanilamide and then transfer to a 10ml Erlenmeyer flask. To a second Erlenmeyer flask add about

44. ## from pg 2...Dr.Bob.

Sorry but I have just a few more Q'sfrom what you said And something that I saw today. Actually I was talking about specific course exams. I've been out of touch for awhile so I don't know all the rules about GRE, SAT, GMAT, etc. Do you mean that I ask

45. ## chem

1.) When determining the melting point it's described in my text as recording 2 points in the melting process. a) when the first drop of liquid is seen b) when all of the compound is liquified and since I have to determine the melting point of

46. ## science(chem)

NaClO3 + H2O + HCl=> what form is the Cl in ? I know that a gas is formed but the reaction that I did also had Cl reacting with the reactants so I'm not sure in what form of Cl did my reactant react with the product of the above reaction. Thanks

47. ## science (chem)

I have a question. I'm forming Isopentyl acetate by the esterfication of acetic acid with isopentyl alcohol. The rxn is shifted so that the ester is produced by using excess acetic acid. In isolating the ester, the excess acetic acid and and isopentyl

48. ## science (chem)

consider a sample that is a mixture of biphenyl, benzoic acid, and benzyl alchohol. The sample is spotted on a TLC plate and developed in a methylene chloride cyclohexane mixture. Predict the relative Rf values for the three components in the sample. For

49. ## science (chem)

This pertains to using a pasteur pipette. I have this weird problem when I use a pasteur pipette. I go and draw the liquid into the pipette and as I'm transfering the liquid to another container it sporatically squirts the liquid in the pipette out as If I

50. ## Lab in general

I just read my syllabus for lab and I am kind of shocked at what it says. I do know that I have to write out procedures of the lab in my nbk before coming to lab but I just read that it says "You will NOT be allowed to refer to you textbook/handout during

51. ## science(chemistry) -Q for Dr.Bob

solvent layer: 1 solid precipitate: no I ran the solvent layer I got in my unknown in the GC and I had sharp peaks in the beginning but at about 4 min on the polar column, I got a broad peak that tailed off considerably. question is, Is it water? I'm not

52. ## referencing sources for chem

I'm not sure how to reference the source if I used the Merck Index. It's the 14th edition and it has the editors and publisher but I'm not sure write the format. The Merck Index An Encyclopedia of chemicals, drugs, and biologicals

53. ## science(chem)

statement from my text says: "like disolves like", This rule is most commonly applied to polar and nonpolar compounds. According to this rule, a polar solvent will dissolve polar(or ionic) compounds and non polar solven will dissolve nonpolar compounds.

54. ## Dr.Bob - Question

I'm know I'm interested in the chemistry field. The problem is that I have to further narrow down my field of interest. I was curious to know what type of chemistry did you specialize in in the past. -christina

55. ## science(chem)

If I have a graph of concentration in Absorbance at 400nm vs [micromolar]of para-nitrophenol The slope would be the extinction coefficient. (y=mx) if forced through 0 The problem is what is y? I know y is the absorbance but it's given on a paper i have as,

56. ## science(chem)

I'm making different concentrations of ethanol and I just wanted to check my calculations and method. Making ethanol concentrations of: 0.40% 0.30% 0.20% 0.10% 0.05% To make the 0.40% ethanol from stock solution using 100ml volumetric flask: (xg

not understanding how to do this. A certain storm cloud has a potential of 1.00x10^8 V relative to the tree. If during a lightning storm, 50C of a charge is transfered through this potential differnce and 1.00% of the energy is absorbed by the tree, how

Based on the question topic posted by Britney below titled:In your opinion (your answer to this reminded me of something) (I posted the same thing there but I thought it was improper to piggyback on that post so I posted this under a new topic) I don't

59. ## Physics..=> drwls - I need your help

I need help seeing if my thoughts are correct and how to do some things. Block 1 of mass 0.200 kg is sliding to the right over a frictionless elevated surface at a speed of 8.00 m / s. The block undergoes an elastic collision with stationary block 2, which

60. ## Dr.Bob => nylon question posted again.since nxt pg

new in bold (copied in normal text) 0.5g hex (1mol/116.21g)= 0.004302mol hex 0.5g adi (1mol/183.03g)= 0.002731mol adi Limiting: 0.002731mol adi(1mol nylon/1mol adi)(226.319g/1mol nylon6.6)= 0.61807 g Nylon Supposed to have theoretically: 0.61807g Nylon

2 blocks are connected by a rope of negligible mass are being dragged by a horizontal force. Suppose F= 68.0N, m1= 12.0kg, m2= 18.0kg and the coefficient of kinetic friction between each block and the surface is 0.100. a.) draw free body diagram for each

62. ## science(chem)

Indicate the correct waste container for the following compounds choices are halogenated organic, nonhalogenated organic, aqueous, and organic solid a)hexane b)methylene chloride (dichloromethane) c)magnesium sulfate d)10% NaOH e)sodium hypochlorite for

63. ## significant figures

82.453 in 3 significant figures with scientific notation. ~hm..I don't know how to do this...it sounds simple but I'm confused. Help please =)

64. ## science(chem)

CH3CHClCH2Cl vs. CH2ClCHClCH3 How would I know if : -The two formulas represent different compounds which are constitutional isomers. -The two formulas represent different compounds that are not isomeric. -The two formulas represent the same compound. ~if

65. ## science (chem)

I have a problem drawing this formula. CH3CH2CH2CH(CH3)CCCH3 The problem is the 2 c's next to each other. I don't know what that's supposed to look like since if it's 1 CH like with the bracketed CH3 it would be connected to that C but I'm confused as to

66. ## Physics => waves

It's a simple problem I think but I can't get the answers to match with the book. A particle fingering flute sounds note with frequency of 880Hz at 20 deg celcius(343m/s => sound wave speed) The flute is open at both ends. a) find the air column length b)

67. ## Some Lab Question (s)

Yes...another calculation problem. Rxn: 1ml isopentyl alcohol + 1.5ml glacial acetic acid + 3 drops sulfuric acid=> isopentyl acetate to calculate the theoretical yield.. I know that the acetic acid is in excess but how would I calculate the theoretical

68. ## SUVs and Cars (Math)

In a parking lot, the # of ordinary cars is larger than the # of sports utility vehicles. by 94.7%. The difference btwn the # of cars and the # of SUV's is 18. Find the # of SUV's. ~My thoughts and work: C= Cars # S= SUV # C-S= 18 (C/S)*100= 94.7% Can I

69. ## science (conversion)

At the time of this books printing the national debt is about \$8 trillion. (a) If payments were made at the rate of \$1000 per second, how many years would it take to pay off the debt, assuming no interest were charged? (b)A dollar bill is about 15.5cm

70. ## mistakes?

hm..I was wondering If someone (cough* me) makes mistakes in answering questions, should they bother answering anything at all? Just a thought that crosses my mind alot. =/

71. ## chemical test

I'm going to do the Baeyer test (Pottasium permanganate) Instructions say to disslove 25mg of unknown or 2 drops of liquid unknown in 2ml of 95% ethanol. Slowly add 1% aqueous solution (weight/volume) of potassium permanganate, drop by drop with shaking,

72. ## Chem drawing

how would I draw this compound? 2-bromo-6-chloro-4,4-dimethylheptane I've tried it again and again but I can't seem to get the Cl on the 6th carbon while still having a 6 carbon chain of heptane I drew it so that it was CH3 CBr CH2 CCH3CH3 CH2 Cl I just

73. ## Chemistry labs in highschool

I was curious to know whether it was standardized practice to have labs for chemistry classes in highschool. I personally have never had labs for chemistry in highschool. In my state we have the Regents. You may or may not have heard of this test, but the

74. ## science?

It wasn't answered before and I hope I don't get reprimanded for asking again...(those sites didn't help) Are bodies fully immursed in formalin (a solution of formaldehyde, water, and methanol) when preserved? And I would assume that they're internal

75. ## science(chemistry)

I have a question about TLC plate solvents. What solvents will leave stains on a plate with a TLC plate out of the ones below and why?) (n-Octane, n-Hexane, Decane, Acetone, 1-Propanol, 2-Propanol, Ethanol, Toluene, Cyclohexane, Methanol, n-Heptane,

76. ## Dr.Bob=> interesting rxn

I was looking at a few videos online. If you type in "top ten amazing chemistry videos" into google and click the first link (wired science), you'll see what I'm speaking of. Well the thing is, I'm curious about the rxn in video # 6. It was described as

77. ## Physics Archimedes buoyancy lab

In calculating the density of a heavy solid. The string holding the heavy solid will cause error. specific gravity= (mass object in air)/ (mass object in air- mass object in water) = density When does it lead to an experimental density that is too high?

78. ## science(chem)

[b]1.[/b]Is TLC a qualitative or quantitative analysis? Is there any way that it can be both? Explain. ~I say it can be both since it can be used to go and determine what exactly is in a sample of mixed compounds which would be qualitative analysis. It can

79. ## Science (chem)

How would you make 300ml of a mixture of toluene and hexane in a ratio of 70:30 respectively? ~I really don't know how I would do this...would I do this?: xT + yH= 300ml xT= 300ml- yH then plug that in? That came out funny though since I get 0 in the

80. ## Science( Physics[ Kinematic eqzns])

Can the Kinematic equations be used if the acceleration is = to zero? ~I know that they can only be used if the acceleration is constant but would zero constitute a constant? I'm not sure about this...because zero would mean that there is no acceleration

81. ## English

I have a question as to how to separate my own opinion from what I have reasearched. I seems that I have a actually blend this all together into a "harmonious" mix so to speak. I would like to learn how to separate this from personal opinion. The thing is

82. ## science(chemistry)

When performing vacuum filtration of a solid in an unknown solvent, is it necessary to go and find out the solvent composition, so that some fresh solvent can be used to wash the filtrate with?

83. ## science(chem)

My lab teacher told me to leave my sample mixture of 2-bromobutane and 2-chlorobutane in a solution 1-2ml of sodium bicarbonate. Then I asked after I had wrapped it up, whether there would be a reaction if I left it there for a whole week since that's what

84. ## polarity

hexane acetone water methanol -order from most to least polar... ~water/methanol, acetone, and hexane.. I can't decide which order does the 3 first go in... Help please...

85. ## Physics, Calculus(alot of stuff together)= HELP!!!

~it was bumped over to the next page so I recopied it and added my answer for the question and was wondering if my integration was correct since you said DrWls:I forgot t use the expression B + Cx for p, and used A + Bx instead. The method of solution is

86. ## science(chem)

If these compounds are shaken in a test tube for 10-20 sec will they form a miscible (1 layer) or immisible (form 2 layers)? a) water and ethyl alcohol miscible b)water and dimethyl ether miscible c)water and methylene chloride immisible d)water and hexane

87. ## science(chemistry)

I have a question about solvent evaporation. If I had an organic layer and an aqueous layer in an unknown mixture of liquids and wanted to obtain the solid of a compound(s) dissolved in the layers, is it reasonable to assume that I can run the compound in

88. ## science(chem)

I was wondering how does one make a saturated chemical solution? I'm supposed to make one, is there a way I can determine the ammount solute needed for a certain amount of solvent? If not, how do I make a saturated solution? Thank you

89. ## science(chem)

I was just wondering if it was necessary to remember each branch of chemistry learned. I can't really remember general chemistry and I'm sort of loosing the organinc. I mostly remember the calculations and the starting part of each course, but other than

90. ## chem-> front page report

wondering if this looks good or should I make the format some other way. Multistep Synthesis of 4-Bromo-2-Chloro-6-Iodoaniline name school Chem###sec## Multistep A,B March 13,2008 Multistep C March 20,2008 Multistep D March 27, 2008 Multistep E April 03,

book says: (4-4.00x + x^2)(6.00x10^-6C)= x^2(15.0x10^-6C) they got: 3.00x^2+ 8.00x-8= 0 I don't get how they got that quadradic equation. (I mulitplied over and then divided the 15.0x10^-6 over and I didn't get what the book got) (my problem that I'm doing

92. ## science(chem)

Hi =) I have two Q's 1. What are the 2 purposes of using a caffine standard during the HPLC process? In general not talking about HPLC I would think a standard is for a)comparing to your own results to see how good your results came out. b) seeing if you

93. ## science(chem)

Consider the following errors that could be made when running the TLC. Indicate what should be done to correct the error. a) A 2 component mixture containing 1-octene and 1,4- dimethylbenzene gave only 1 spot with and Rf value of 0.95. The solvent used was

94. ## science(chem)

For the reaction: acetic acid (2g) + Isopentyl alcohol (0.9g) => Isopently acetate(1.15g)+ H2O I'm suposed to determine the limiting reagent, theoretical yield and percent yield from this reaction but the reaction was given as a picture... I'm not sure

95. ## Science (Physics)...........F=ma and tension.

2 crates shown in the figure below are on a horizontal frictionless surface. The woman is wearing golf shoes for traction as she applies a horizontal force of F= 50.0 N to the 6.00kg crate. The ropes are of negligible mass. Smaller box weighs 4.00kg a)

96. ## Science(chem [Solubility])

This pertains to the Merck Index. I would have to say that the exact solubility is not very clear like for ex. Sodium Sulfate solubility listed is: Sol in ~3.6 parts water -I don't know what to make of this information since If I have to fill up a chart

97. ## science(chem) Dr.Bob Question from before

The only reason I asked about the balance is that most analytical balances in use in schools weigh to the nearest 0.1 mg although that may have changed since I retired. There are semi-micro balances that weigh to 5 places and micro-balances that weigh to 6

98. ## science(chem)

I'm doing an experiment and I'm supposed to have neutral basic and acid samples of solution. I just wanted to make sure that I knew which was which. (If I'm incorrect, please correct me) Acid: 0.7ml 10% H2SO4 + 0.7ml 10% Na2WO4(sodium tungstate) Basic:

99. ## science(chem)

I have a question about distillation. Or heating in general. When something says heat for 1hr or 1/2 hr do you start counting when you turn on the hotplate? Or do you start counting when the mixture is boiling? I have a feeling that this issue is affecting