288 Answered Questions for the topic Chemistry Lab

02/18/18

Precipitate (Chemistry)

Given a "substance A" that reactswith a "substance B" to form aprecipitate. If you have an "unknownsolution" and add some substance Bin it, and get a precipitate, does itmean that your "unknown"... more

02/12/18

During the experiment, you recover 2.8 mg of Fe by testing 100 mg of powder.

Assume a full pill weighs 300 mg and contains 27.0 mg of Fe. What is the % recovery for your experiment? In other words, what percentage of the total Fe in the pill did you recover?

02/11/18

Order of Reaction and rate constant

The total pressure in atmospheres was recorded during the decomposition of acetaldehyde (CH3CHO(g)) at 701K for certain time intervals shown in the chart. Use the information to answer the... more

02/08/18

Brewing tea and water together

Say I have a pot of brewed tea containing only the tea and water. Is there a specific ratio of the two ingredients that prevails to actually call the compound tea?

01/29/18

how many grams of sodium hydroxide are needed to prepare 235 ml of a 5.0% (m/v) solution?

need help. please axplain and describe the work needed to get to answer if possible.

01/29/18

How many gm/mL of glucose and water are in 500mL of a 5.3% glucose solution?

This is a measurement lab for cell and molecular biology, however preparing concentrations by using w/v%, v/v, etc.

01/29/18

When a student mixed 46.1 mL of 0.100 M NaOH with 50.0 mL of 0.100 M HCl, they found that 144.5 J of energy was produced.

Based on these results, what is the molar heat of reaction in kJ per mole?

01/29/18

If you mix 45.4 mL of 1.000 M NaOH with 45.4 mL of 1.000 M HCl, what is the concentration of NaCl(aq) in the resulting solution? Report your answer to one deci

Help, I do not know where to even begin with this question! Due in less than 2 hours!

01/28/18

How do you round .47 to the ones place?

Would it be 0 since the four is less than 5? Or would the 7 round up the 4 which would then make it 1? 

01/22/18

Hi! Are Delta Hsolution and Delta Hreaction the same value in dissolution?

Hi! Are Delta Hsolution and Delta Hreaction the same value in dissolution? Please help! I know qrxn and qsolution are opposite(signs). I'm confused as to if DeltaHsolution and DeltaHreaction are... more

01/04/18

Calculate the mass of 4.5×10^ 8 molecules of nitrogen

Calculate the mass of nitrogen molecules give the molar number

12/12/17

A Zn wire and Ag/AgCl reference electrode (E° = 0.197 V) are placed into a solution of ZnSO4.

A Zn wire and Ag/AgCl reference electrode (E° = 0.197 V) are placed into a solution of ZnSO4. The Zn wire is attached to the positive terminal and the Ag/AgCl electrode is attached to the negative... more

12/11/17

A Zn wire and Ag/AgCl reference electrode (E° = 0.197 V) are placed into a solution of ZnSO4.

A Zn wire and Ag/AgCl reference electrode (E° = 0.197 V) are placed into a solution of ZnSO4. The Zn wire is attached to the positive terminal and the Ag/AgCl electrode is attached to the negative... more

12/04/17

Preparing 5 dilutions of 0.200M NiSO4?

I’m supposed to be preparing five dilutions from 50.0 mL of 0.200M NiSO4 stock solution. Instructions say that I will need standard solutions with five different concentrations and all standards... more

12/02/17

Preparing 5 dilutions of 0.200M NiSO4?

I’m supposed to be preparing five dilutions from 50.0 mL of 0.200M NiSO4 stock solution. Instructions say that I will need standard solutions with five different concentrations and all standards... more

12/02/17

Galvanization

I'm a little confused on how to find the mass of zinc consumed from the data: Mass of zinc produced: .745g Mass of Zinc electrode before 7.705g Mass of Zinc electrode after 8.450g Length of... more

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.

11/29/17

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

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?

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 

11/14/17

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

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
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