294 Answered Questions for the topic Chemistry Lab

Chemistry Lab Science Chemistry Lab

11/30/17

We can prepare oxygen gas by decomposing hydrogen peroxide. There are many other chemical reactions that generate gases as one of their products.

Lets consider the reaction between zinc metal and hydrochloric acid as such an example. Write a procedure that explains how you would collect the gas produced from this reaction in the laboratory.

chemistry help

Calculate the emf of the voltaic cell: Concentration of Mg+2 (anode)  is 0.00100 M and Fe+3 (cathode) is 0.100 M   unsure how to find this
Chemistry Lab Chemistry Spectrometry

11/28/17

Effects of changing concentration of a solution?

If you change the concentration of a solution, will the molar absorption coefficient change? why?
Chemistry Lab

11/25/17

indicating the total number of ions present in a solution

Chemical Formula of Salt NaI Cation Na+  Anion I- What is the total number of ions in 1.0 L of a 1.0 mol/L solution 

chemistry prelab question

Potassium permanganate (KMnO4) is the oxidizing agent and sodium oxalate (Na2C2O4) is the reducing agent.a. Manganese (Mn) is reduced.b. Carbon (C) is oxidized.   2KMnO4(aq) + 5Na2C2O4(aq) +... more
Chemistry Lab

11/04/17

Question dealing with gravimetric analysis lab.

Approximately how many mL of 5% BaCl22H2O solution would be required to precipitate all the sulfate if we assume that your samples are pure sodium sulfate? Assume that the density of the barium... more

11/01/17

Refractive Index - ORGANIC CHEMISTRY LAB

A student attempts to separate a sample of cyclohexane and ethylbenzene by distillation. After the distillation the student obtains an n 20D of 1.4355 for what should be pure cyclohexane with a... more

10/31/17

Tea contains about 3% caffeine by mass. Assuming each tea bag contained 2.25 g of tea, did you recover the expected amount of caffeine from two tea bags?

So what is the expected amount of caffeine? Is it 0.0675g or is it 0.135g?  In lab, I recovered 0.018g of caffeine
Chemistry Lab Chemistry

10/28/17

why is it that we can obtain a Raman spectrum

If vibrational transitions correspond to energies in the IR region of the electromagnetic radiation, why is it that we can obtain a Raman spectrum by using a visible wavelength laser as a light... more
Chemistry Lab

10/23/17

Data Table 4: Reaction of Rocks with Hydrochloric Acid

This is from a lab about acid rain
Chemistry Lab Forensic Scence

10/22/17

presumptive luminol test

  What role does the hydrogen peroxide play in the reaction? A: Is it the the oxidizing agent and blood in the catalyst?   How would you describe to jury about the scientific basis for this test.
Chemistry Lab Math Science Chemistry

10/20/17

How do I calculate the pressure in a 12.2L vessel that contains 2.34g CO2, 1.73g SO2, and 3.33g Ar at 42 degrees Celsius?

Can you please help me with this problem? Thanks
Chemistry Lab Science Chemistry Physics

10/20/17

I am struggling with this AP Chemistry word problem

A 255mL round-bottom flask is weighed and found to have a mass of 114.85g. A few mL of an easily vaporized liquid are added to the flask and the flask is immersed in a boiling water bath. All of... more
Chemistry Lab

10/18/17

Can Flame Test identify any unknown element?

 Explain why or why not

10/17/17

Chemistry Paper Chromatography

A chemist wishes to separate and identify a mixture of substances using paper chromatography. The diagram shows the apparatus used. The solvent is water.The solvent front is allowed to reach the... more
Chemistry Lab Chemistry

10/16/17

Ion exchange column estimate

The question is: Suppose another student attempts to do an ion exchange on a column that is already nearly saturated with Co2+ and Zn2+. Will his calculated % Co be high or low?
Chemistry Lab Organic Chemistry

10/15/17

Provide the chemical reaction being demonstrated in the experiment. it should include the starting materials, reagents, and products.

Procedure:1) Accurately weigh approximately 0.40 g of Dimethyl maleate into a 50 mL round bottom flask that possesses a ground glass joint, and record the weight.2) Dissolve the Dimethyl maleate in... more
Chemistry Lab Biology Tutor

10/12/17

volume of PCR , is this right?

Reagent stock concentration             Required final concentration                Volume10X Buffer                                                       1X                                       5... more
Chemistry Lab

10/11/17

Compare the reactions of CuCI2 and HCI with AgNO3.

 Compare the reactions of CuCI2 and HCI with AgNO3. Propose a hypothesis to account for the reaction product. Hint: What is the likely chemical formula for the product?
Chemistry Lab

10/11/17

How can this lab illustrate this fact

person is slightly denser than water. Life preservers are made of low density materials.  The average density of a person plus a life preserver is less than density of water- so together they will... more
Chemistry Lab

10/11/17

what process must be performed during clean up; filtration, distillation or chromatography? Why?

What process must be performed during clean up: filtration, distillation or chromatography? Why?

10/05/17

When compound A is partitioned between equal volumes of methylene chloride and water

When compound A is partitioned between equal volumes of methylene chloride and water one finds that the partition coefficient is equal to 1. This means that the compound happens to be equally... more
Chemistry Lab Chemisty

10/05/17

Percent Composition

Calculate the percent composition of each element, by mass, in Na2CO3*10H2O
Chemistry Lab Dna

10/02/17

where do you think the bacterium that produces HindIII is found?

The optimal working temperature for the restriction endonuclease HindIII is 37°C
Chemistry Lab

09/30/17

Molar abosrptivity

Calculate the molar absorptivity 1. Blue Dye (concentration 40mg/L) (Peak/ λmax is 630) 2.  Red Dye (concentration 60mg/L) (Peak/ λmax is 520) 2. Red Dye (concentration 70mg/L) (Peak/ λmax is... more

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