# Questions tagged [concentration]

The concentration characterizes the composition of a mixture with respect to the volume of the mixture. There are mass, amount, number and volume concentrations. Related and within the scope of this tag are normality, molality, mole fraction/ratio, mass fraction/ratio.

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### Electronic oxygen concentration sensor

I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer ...
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### Co49Ni21Ga30 - molar mass and density

I need to calculate the molar mass and density of the shape memory alloy $\ce{Co49Ni21Ga30}$ (I suppose the numbers indicate the mass percentage). To get the molar mass, is it correct to use the ...
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### Osmolarity and osmotic pressure

You have discovered a new strain of bacteria called Tankeromyces subtilis that has a special outer membrane that is capable of withstanding high levels of osmotic pressure. These bacteria can survive ...
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### How to calculate the concentration based on dilution of a stock solution?

One of my exam questions is about lipstick and calculating the amount of lithium in the lipstick by AAS. The determination took place by making standard solutions with known concentrations of lithium. ...
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### Why is the concentration halved at the intersection of Hg²⁺/Hg₂²⁺?

For the couple $\ce{Hg^2+}/\ce{Hg2^2+}$: $E^\circ = \pu{0.91V}$. At the border the concentration is $c = \pu{0.10 mol \cdot L-1}$ for all ions. Hence build the stability diagram of mercury. I have: ...
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### Alkaline glycine buffer molarity

Having never prepared a buffer solution before, I am hoping for a little help in understanding the process. This method I plan to use calls for a $\pu{0.1M}$ glycine buffer at pH $10.6$. Some ...
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### How to calculate an equilibrium constant from concentrations and a reaction equation [closed]

2.50 mL of 0.0150 M A, 3.50 mL of 0.0250 M B, and 4.00 mL of distilled water were added to a 50-mL beaker. At equilibrium the concentration of C is 2.05*10^-3M at 25degrees celsius. Calculate Kc for ...
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1 vote
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### What is the equation that demonstrates the relationship between molar conductivity and temperature?

Can someone please help me find the equation that defines the relation between molar conductivity and temperature. I have found some information, but it was not really that much complete.
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### NaClO Concentration

In my previous occupation the usage of bleach--$NaClO$--I found was quite staggering, and based off of the health issues that I and other coworkers were having, I wanted to see how close we were ...
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### Representing woody biomass concentration for kinetic reactions

Woody biomass is composed of cellulose, hemicellulose, and lignin components. The following diagram provides representative formulas for each component: Biomass can be represented by it's density, ...
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### Determine molecular weight of biomass based on ultimate analysis [duplicate]

The ultimate analysis (by weight percent) for beech wood is: $$\ce{C}=49.05\,\%,\; \ce{H}=5.83\,\%,\; \ce{O}=45\,\%,\; \ce{N}=0.12\,\%$$ Using the ultimate analysis values, the molar mass of each ...
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### How many moles NH4Cl must be added to NH3 to create buffer with pH=9?

How many moles of $\ce{NH4Cl}$ must be added to $\pu{2.0 L}$ of $\pu{0.10 M}$ $\ce{NH3}$ to form a buffer with $\mathrm{pH}=9$? Assume the addition does not change the volume of the solution ...
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### Experimental difficulty with the iodine clock reaction

I did the iodine clock reaction using sodium metabisulfite and potassium iodate. As I understand it, increasing concentration is supposed to speed up your reaction rate. I did 10 trials. The first 5 I ...
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### What is the minimum number of given sets of information required to complete an ICE chart for an equilibrium reaction?

I'm considering creating a program that automatically completes an ICE chart/table when the minimum given information is provided. The reason I'm posting my question here is because I need to know the ...
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### Calculate species concentration from first-order kinetic reactions

I am trying to determine the concentration of products from the kinetic reactions of wood pyrolysis. The kinetic scheme separates the wood into cellulose, hemicellulose, and lignin. For example, the ...
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### Finding new pH after NaOH added to buffer solution

I have a buffer containing 0.2 M of the acid $\ce{HA}$, and 0.15 M of its conjugate base $\ce{A-}$, with a pH of 3.35. I need to find the pH after 0.0015 mol of $\ce{NaOH}$ is added to 0.5 L of the ...
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### Determining [CO2] of a sample in ppm

I have 20mL gas samples and I need to determine the [CO2] in ppm. I have a Li-Cor 6200 with a closed loop, so essentially I will inject a volume of gas into the loop and the change in the output is ...
1 vote
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### How to calculate concentration of hydrogel nanoparticles [closed]

I have prepared hydrogel nanoparticles in aqueous solution. How to calculate concentration of hydrogel nanoparticles ?
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### Molarity vs Normality in labeling sulfuric acid

Molarity (M) is defined as moles of solute per liter of solution while Normality (N) is defined as moles of reacting units per liter of solution. Most texts use sulfuric acid as an example to ...
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### Estimating the protein concentration of an unpure protein solution

I'm confused on this problem for estimating protein concentration. Upon first glance, it looks like a simple Beer's law problem. but then there's the issue that the protein is not pure. How do I ...
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### Mass of "orange" in 25% orange juice [closed]

Hypothetical question: Knowing that orange juice has 25% concentration of orange. And knowing mass of juice which is 200g. What ...
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### How could click reaction take place at low concentration?

I have DBCO-functionalized resin, and the DBCO group is validated with FAM-azide. But I cannot use this resin to react with FAM-Azide-labled primer, which has very low concentration (20 μM, it is ...
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### Preparing CdSe electrodeposition bath

What is the best way of preparing an aqueous solution containing 5 mM $\ce{CdSO4}$, 1 mM $\ce{SeO2}$, 0.5 M $\ce{Na2SO4}$ and adjusting pH to 3 by adding 0.5 M $\ce{H2SO4}$? What is the ...
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### Heat energy of phosphoric acid evaporation

Looking at a system in which phosphoric acid is concentrated in an evaporator which uses a constant recycle stream with a heat exchanger in this stream to heat the acid so that water evaporates out of ...
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### Find amount of acid and base required to make buffer

I am wondering if it is possible to know exact amount of acid and base that we can put in together to make a buffer. I want to make a 0.05 M extraction buffer using disodium hydrogen phosphate (DHP) ...
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### Are all strong acids the same strength?

Since the six strong acids dissociate completely into their ions, and the reaction goes to completion, does this mean that acids such as $\ce{HI}$ and $\ce{HCl}$ have the same acidic strength? I know ...
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### How to interpret the instruction of the dilution of hydrogen peroxide?

I am required to prepare $\pu{120cm3}$ of hydrogen peroxide to each of one of my students tomorrow. Some material is given to me on the method of preparing the solutions. Within the method of ...
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### Does the water in hydrates affect final concentration?

Say I have a hydrate, and I am going to dissolve it in water. Does the water in the hydrate affect the final concentration? Here's an example: If I have $\pu{249.69 g}$ of $\ce{CuSO4·5H2O}$, and ...
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### Does concentration of salt increase or decrease rate of rusting?

I want to know whether increasing the concentration of salt, specifically $\ce{NaCl}$, increases or decreases the rate of rusting. There are conflicting theories that explain opposite outcomes: ...
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### How to explain the increase in current with the increase in the concentration of responsible ions?

I have conducted an experiment wherein I have used different concentrations of $\ce{H2SO4}$, $\ce{HNO3}$ and $\ce{H3PO4}$ as the electrolytes. I filled the acid in glass tube and used a 9V battery, ...
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### Molality of solution having more than one solute?

So here is my question, Question: A water sample contains 9.5% $\mathrm{MgCl_2}$ and 11.7% $\mathrm{NaCl}$ (by weight). Assuming 80% ionization of each salt. Boiling point of water will be ________....
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I am unsure how to go about solving this question. I know how to get the osmotic pressure, but where do I go from there? I can't use the gas law since the protein is not a gas. $\pu{2.38 g}$ of a ...