294 Answered Questions for the topic Chemistry Lab

11/12/16

Beers Law plot

I had to constructed a Beers Law plot for my graph (absorbance vs. concentration) I'm supposed to find the molar extinction coefficient from the slope. Well the slope of the line is... more

11/12/16

Spectrophotometric lab

A test for drug use involves addition of 10.00mL of colorless reagent to 10.00 mL urine. If drug residue is present in the sample the solution turns blue(λmax = 605 nm, ε = 18,200M-1cm-1). Because... more

Why does each gas show a colour only when electricity was passed through the discharge tube

we used an apparatus containing a power source and gas discharge tubes we then looked through diffraction grating and observe the spectra produced by each gas discharge tube
Chemistry Lab Light Spectrum Chem11

11/07/16

What do the different colours in a line spectrum represent?

grade 11 chemistry lab on atomic emission spectrum

11/06/16

Percent yield & Limiting reagent

If a students adds three times as much phenanthroline than she was supposed to when attempting the red crystal synthesis how does this effect the actual, theoretical and percent yield?
Chemistry Lab

11/02/16

Of all the measurements required to determine the delta H reaction which is likely to produce the greatest error and why

The lab's topic is Hess' Law and Calorimetry and the objective is to determine the heat formation of MgO using calorimetry and Hess' Law. 
Chemistry Lab

11/01/16

I have a chem lab due and it gives the following reaction Cu(s)+4HNO3(aq)->Cu(NO3)2 (aq)+2NO2(g)+2H2O(l)

then theres a chart and it asks for the mass or volume to be used or produced (g or mL) , Molar mass(g/mol) Molarity and diluent (if a solution) and moles used or produced. IDK where to get these... more
Chemistry Lab

11/01/16

I have a lab due where it asks for the chemical reaction which is : Cu(s)+4HNO3(aq)->Cu(NO3)2(aq)+2NO2(g)+2H2O(l)

then theres a chart and it asks for the mass or volume to be used or produced (g or mL) , Molar mass(g/mol) Molarity and diluent (if a solution) and moles used or produced. IDK where to get these... more
Chemistry Lab Chemistry

10/31/16

How many double bonds?

How many double bonds does the molecule CCl4 have?
Chemistry Lab Chemistry Stochiometry

10/29/16

Stoiciometry & Limiting reagent

In the reaction A + 2B ---> 3C + D , If 93g of A and 85g of B are combined, which reactant is the limiting reagent, and what is the theoretical yield of C in grams? (MM(A)= 55g/mole, MM(B)=... more
Chemistry Lab

10/23/16

Serial dilutions. Need help with my lab

PART A    Mass of empty weighing dish=2.0795g Mass of weighing dish+NaOH=2.1808g Mass of NaOH=0.1013g Final Volume of NaOH stock solution A=50mL Concentration of NaOH stock solution = ? For that... more

10/15/16

Im trying to figure out the answer

Now consider whether this relationship holds true for a process more complex than simple gas speed: diffusion. Use the molar masses of NH3 and HCl to calculate the predicted ratio of their... more

If salt and citric acid are mixed, is it a physical or chemical change?

What about between: Salt and NaOH (Sodium Hydroxide) Potassium Chloride and Distilled Water Potassium Chloride and Citric Acid Potassium Chloride and Vegetable Oil Potassium Chloride and... more
Chemistry Lab

09/29/16

A piece of aluminum foil with mass 1.65g has the length and width dimenstions of 15.0cm and 15.0cm. Using the formulas given and the literature value for the de

density=2.6989 formula= mass/volume=mass/(l)(w)(t)
Chemistry Lab Chemistry Elements

09/28/16

Calculate the number of grams of each element...

Calculate the number of grams of each element in 100 g of phenolphthalein if the compound is 75.46% C, 4.43% H, and 20.10% O by mass. Convert each to moles.

09/22/16

Why doesn't NaCl and HCl have the same effect on an equilibrium reaction

Recently in my AP Chem class we did a simple reaction demonstrating equilibrium: [Co(H2O)6]2+(aq)(pink) + 4Cl-(aq) <--> [CoCl4]2-(aq)(blue) + 6H2O(l) (in an ethanol solution). The reaction... more

09/16/16

what state of matter would you expect fluorine to be at -200 degrees Celsius

what state of matter would you expect fluorine to be at -200 degrees Celsius?

why is the temperature constant when a pure substance melts and freezes?

why is the temperature constant when a pure substance melts and freezes?
Chemistry Lab Chemistry

09/05/16

Phenol is the active ingredient in some throat sparys.

It is a solid, soluble in water, and it naturally sublimes at room temperature.   a) What is one way you could separate phenol from salt?   b) What is one way you could separate phenol from sand?

09/05/16

Chemistry Conversion

Convert 354.2 milliliters to quarts, given 1,000 milliliters = 1 liter and 1 quart = 0.94 liter

09/05/16

Chemistry Conversions

A) Convert grams to pounds by converting grams to kilograms and then kilograms to pounds. Then solve:   35.4 g/1 X 1 kg/1000 g X 2.2 lb/1 kg     Solve:   B)1,324,000 ug/1 X 1 kg/10^6 ug

08/30/16

Intro Biology Question regarding water (chemistry related)? PLEASE HELP!

Which statements about water and 'anti-water' (something that is the opposite of water in terms of molecular properties) should be true? Select one:a. Lubricants such as engine oil must work... more
Chemistry Lab Chemistry

08/30/16

. The normal audible threshold for sound pressure is 20 micropascals. If you play the child a pure tone at 1.58 X 10^-4 bells of sound pressure,child detect so

The end of the question is will the child detect the sound?  SHOW ALL WORK!  Use the conversion factor 1Pa (Pascals)= 94 dB (decibels) 

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