305 Answered Questions for the topic Chemistry Lab

01/22/17

Make 250ml of a 0.15% H2O2 solution. You will be provided a 1.875% solution of H2O2.

show all calculations and explain how I would get the answer with this information. 

01/22/17

calculate how many ml of 3.0% h2o2 to use to make 500ml of 1.0% h2o2.

Show all calculations
Chemistry Lab Biology Chemistry Vitamins

01/05/17

Is there a way to calculate yourself the content of vitamin B12 of a food?

I really need to know if it's possible to calculate the amount of B12 existent in different foods, is it possible to calculate it myself? I can't just research it on the internet. 
Chemistry Lab

12/01/16

i have a question on this

Given the true mole masses of CuSO4 (160 g) and H2O (18 g), how could you find the exact formula of the hydrate from your experimental data? That is, how could you find the value of x in the... more

11/25/16

Finding how high a column of water in meters can be with the density of water and mercury

I'm struggling to understand what the question is asking me and what concepts it is trying to test...    If the density of water is 1.00g/mL and the density of mercury is 13.6g/mL, how high a... more

11/23/16

Calculating Enthalpy in a Calorimeter Experiment

When 25.0 mL of 1.0 M H2SO4 is added to 50.0mL of 1.0M of NaOH at 25.0 degrees C in a calorimeter, the temperature of the aqueous solution increases to 33.9 degrees C. Assuming that the specific... more

balanced combustion reaction for C6H6

Equation: 2C6H6(l)+15O2(g)--> 12CO2+6H2O(l)_6542 KJ   If 5.900g of C6H6 is burned and the heat from the burning is added to 5691g of water at 21 degrees Celsius, what is the final temperature... more
Chemistry Lab Chemistry

11/17/16

Titration Calculation?? PLEASE HELP!!

Suppose our unknown acid was acetic acid, CH3COOH (Ka = 1.8 x 10-5) and that your initial aqueous solution contained 0.100 mol of acetic acid in total volume of 100 mL.To this acetic acid solution... more
Chemistry Lab

11/17/16

How do I make a buffer with buffer capacity of 35.0 mM?

I have to make a buffer with a pH of 7. The solution's buffer capacity has to be 35.0 mM. Then I have to calculate how many mL of .1 M HCl will break my buffer. The professor will come around and... more
Chemistry Lab Chemistry

11/14/16

What is heat and temperature

What Is heat and tenperature

11/14/16

Calculate the experimental specific rotation (°) of the equilibrium mixture of α- and β-lactose

Calculate the experimental specific rotation (°) of lactose at time equals zero (t = 0)=87Enter the observed rotation of the equilibrium mixture of α- and β-lactose (°)=5.2 Calculate the... more

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)

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