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# 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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### How to find amount of substance of a solute given molarity and volume of solution? [closed]

We know $\pu{1 M}$ is mole of solute per liter of solvent, and I have $\pu{500 mL}$ solution of $\ce{NaOH}$ which is half a liter of $\pu{1 M}$ $\ce{NaOH}$, does that mean I have $3.01\times 10^{23}$ ...
41 views

### Estimation of Sodium Hydroxide

Why is estimation of sodium hydroxide more accurate with oxalic acid rather than with sulfuric acid or any other strong acid?
24 views

### How and why do concentrated solutions react faster? [closed]

It seems intuitive that concentrated solutions would react faster, but, when I stopped and thought about it, I got confused. Wouldn't concentrated acids and bases be in contact with less water than ...
69 views

### How do we weigh one C atom? [closed]

As far as I get it, we did weigh one carbon (12,6-isotope) atom. Then we said that electrons have nearly zero weight and protons weight nearly the same as neutrons. Hence we took the weight of that ...
34 views

### Up to which dilution can one assume that 1 mg/l = 1 ppm?

For aqueous solutions it is often assumed that 1 milligram per liter equals 1 ppm. Are there any guidelines up to which concentration this shortcut is admissible? Are there any formulas which ...
45 views

### Why does the electrical conductivity increase as the temperature decreases?

I am measuring the dependence of electrical conductivity of ( NaCl and $\ce{CH3COONa}$ solutions with concentration 9g/L) with temperature using conductivity meter. Theoretically the conductivity ...
476 views

### Can I express the rate of a reaction as percent per second (%/s)?

Rate is calculated as change in concentration over change in time, so usually $\pu{M/s}$ $(\pu{mol L-1 s-1}).$ Say, I'm calculating it for $20\%$ solution of ammonium hydroxide, so my final rate is ...
19 views

### Calculating concentration of a powder in a liquid

I'm trying to determine how to calculate proper measurements for a 5% concentration of a vitamin C ester powder (ascorbyl palmitate) mixed in a 50/50 carrier oil mixture (jojoba oil/squalane oil) with ...
37 views

How many moles of $\ce{Na2SO4}$ we have to add into a saturated $\pu{0.5 L}$ solution of $\ce{Ag2SO4}$ so that the concentration of $\ce{Ag}$ is $\pu{4.0 \times 10^-3 M}$? ($K_\mathrm{sp} = 1.4 \times ... 3answers 152 views ### I have a solution of citric acid, tartaric acid, water and glucose. How do I find the concentration of the citric acid present in the solution? If I try to find the concentration of citric acid through back titration or reverse titration, the base I would use, like NaOH, would react with both acids to form sodium citrate and sodium tartrate, ... 1answer 30 views ### What formula allows adjusting balance of (Ethyl Alcohol / Water / Caffeine powder) to know concentration for the Caffeine solution? I am experimenting with different levels of concentrated caffeine solution. The solution has a small percentage of ethyl alcohol, in the$\ce{H2O}. Problems encountered too much ethyl alcohol ... 3answers 76 views ### Electrochemistry conditions for voltage to increase in a galvanic cell I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always? Consider a standard cell of ... 1answer 39 views ### An exception to the IUPAC convention for italicisation (typography) According to IUPAC, only physical quantities and variables must be italicised. Section 8 Use of Italic and Roman Fonts for Symbols in Scientific Text of ICTNS Guidelines for Drafting IUPAC Technical ... 2answers 1k views ### What is the difference between chemical equilibrium and dynamic equilibrium? Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant. Dynamic equilibrium from ... 1answer 57 views ### Does the volume change when the reactions occur? [closed] I have this reaction (all substances are gaseous): \begin{align} \ce{A + 4.5 B &→ C + 2 D + 2 E}\tag{R1}\\ \ce{C + 7.5 B &→ 8 D + 2 E}\tag{R2} \end{align} Does the volume change when ... 1answer 175 views ### How to dispose of NaOH solution? [closed] I have a range of sodium hydroxide solutions with different concentrations. (from 1.0 mol dm^-3 to 0.5 mol dm^-3). The max volume of each is 100ml. How can you easily dispose of these? Can I pour them ... 1answer 74 views ### How to calculate the number of protons in a sphere given the volume and the pH? The spherical radius of a nano-droplet of a solution (\mathrm{pH}$of which is$6$) is given as$\pu{20nm}$. I can find the molar concentration of$\ce{H+}$and subsequently the number of$\ce{H+}$... 1answer 47 views ### Calculating the Ionic strength of sodium acetylsalicylate With the addition of aqueous NaOH to an aspirin solutions in water the reaction will yield products of sodium acetylsalicylate and water. I would like to measure the amount of sodium apsirin formed ... 1answer 74 views ### Meaning of mass concentration “units” % m/v [closed] In a saline solution that is 5.750% (m/v) potassium iodide$(\ce{KI}),$there are: a) 5.750 mL$\ce{KI}$per 100.0 mL$\ce{H2O}$b) 575.0 mg$\ce{KI}$per 10.00 mL of$\ce{KI}$solution c) 5.... 0answers 37 views ### Angels Share seems bogus What is the explanation of barreled spirits (at 62.5% ethanol) that undergo changes in concentration of ethanol. Whereas the volume after aging is typically reduced, the proof varies between low 100 ... 2answers 109 views ### Shouldn't mineral NPK fertilizer ingredients add up to 100%? I use a mineral based fertilizer in powder form which - according to the label - should not contain any fiber and is fully soluble in water (I dissolved 2 times the recommended dosage and found no ... 2answers 62 views ### Ratio of Water to Isopropyl Alcohol? [closed] I am looking for a very simple formula to calculate the ratio of water to 99% isopropyl alcohol that I need to prepare a solution with a density of 0.925 g/cm3. I am assuming there is one. 1answer 45 views ### Determining the hydrogen peroxide content in acetic acid [closed] For a project I have to determine the peroxide content in some samples, for which we plan to use glacial acetic acid. Unfortunately, I don't know the peroxide content of my acetic acid and because we ... 1answer 43 views ### How to find osmolarity of a solution contatining salt and glucose? What is the osmolarity of a solution that contains$4.00\%$(m/v)$\ce{NaCl}(M = \pu{58.44 g mol-1})$and$3.00\%$(m/v) glucose$(M = \pu{180.18 g mol-1})?$I know you have to convert percentages ... 2answers 74 views ### Can the rate of reaction of a Voltaic/Galvanic cell be determined theoretically? I am conducting a chemistry practical in which I measure the voltage of a Zn-Cu Voltaic cell over time. Assuming that the surface area of the electrodes are known, concentration of reactants are ... 1answer 112 views ### Calculation of VOCs concentration (ppm) in the headspace of a bottle What is the right way to calculate the concentration of volatile compounds in the air in a closed container? Suppose we have a$\pu{50 mL}$bottle with$\pu{25 mL}$of$100\%$ethanol$(\ce{EtOH})$... 2answers 658 views ### How to convert P2O5 concentration to H3PO4 concentration? Why are some elements such as phosphorus reported as$\ce{P2O5}$concentrations when the materials have no$\ce{P2O5}$in them. I would like an explanation of how the conversion is done between real ... 1answer 76 views ### 10 g of NaCl is dissolved in 250 g of water. The mass fraction and molality of the solution is 10 g of NaCl is dissolved in 250 g of water. The mass fraction and molality of the solution is For calculating mass fraction, simply divided$10/250$to get$0.04$. My book says it’s wrong. Is mine ... 1answer 62 views ### Bracketing Standards and dilutions You are running an ICP-MS (Inductively coupled plasma mass spectrometry), with bracketing standards of 10 ppm(mg/L) K+ and 100 ppm K+ and sample of 500 ppm, prepared 5 mL diluted to 100 mL. Shouldn’t ... 1answer 48 views ### Constant concentrations in solution I'm a high school student considering the concentration of solutions, and whether the concentration is constant at the bottom or towards the surface. Even then, how would I know that the solution is ... 0answers 19 views ### Removing potash from water using poly-aluminum chloride I have been conducting an experiment for a school project, (removing metals from water)I added 50 grams of sulphate of potash to 2 litres of water, then allowed it to dissolve for a 24hrs. On two ... 1answer 38 views ### Numerical simulation and calculations of pH a. Reaction of$\ce{CO2}$addition in water is as follows:$\ce{CO2}$+$\ce{H2O}\ce{->}\ce{H2CO3}$b. Then, pH of$\ce{H2CO3}$solution is increased to 12 by addition of 1M$\ce{NaOH}$. ... 1answer 52 views ### Is the density of solute same as the density of solution? [closed] This problem came up while solving some problems on mass percentage and mole concept. Essentially, our teacher said that the$w/w\%$and the$v/v\%$for a given solution will be the same, because in ... 1answer 267 views ### One mole of solute (NaCl) is dissolved in 1 litre water. The molarity of solution is [closed] One mole of solute ($\ce{NaCl}$) is dissolved in$\pu{1 L}$of water. The molarity of the solution is: A)$\pu{<1M}$B)$\pu{>1M}$C)$\pu{=1M}$D)$\pu{=2M}$My answer: It’... 1answer 60 views ### How would I find the molarity/concentration of a gas using pV = nRT? The problem I'm working on is: At$\pu{1100 K}$and a total pressure of$\pu{1 atm}$,$\ce{SO3}$is$75.0\%$dissociated. $$\ce{2SO3(g) <=> 2SO2(g) + O2(g)}$$ Assume$\pu{1.00 mol}$... 0answers 18 views ### Viscosity and concentration of solutions I will need a fluid around a specific viscosity, using a mixture of water and something like sugar. Is there a way to calculate viscosity based on concentration? 1answer 81 views ### How to distinguish mass concentration and density? I am writing a proof where I have to mention both with density and of a material and mass concentration (mass/volume) of a material. I am using the letter$\rho$to represent density, and I didn't ... 1answer 64 views ### What does pH of NH3 solution refers to? I was introduced with an exercise which asks to find$K_\mathrm{b}$of$\ce{NH3}$when the$\mathrm{pH}$of$\ce{NH3}$solution with concentration$M_1$. Well, in order to solve it, I used the fact ... 1answer 20 views ### How do I calculate the correct sample concentration for my measurements? I will measure absorbance for measurement of protein concentration. The sample solutions are prepare in serial dilutions to the volume of 100 uL to obtain a certain concentration of the protein in ... 0answers 23 views ### What is the equation that describes the variation in concentration of an inhibitor in an heterogeneous catalysis? I find myself in quite a pinch: I have to sustain a Chemical Physics exam, and I know for a fact that the professor often asks this particular question: Suppose that we have both a reacting species ... 2answers 111 views ### Density and concentration of hydroiodic acid [closed] I weighted my hydroiodic acid sample: 25 ml weight 34.1 g, so the density is about 1.364 g/ml. I want to know its concentration based on density. Does anyone have the corresponding density chart? 0answers 36 views ### Arrhenius equation using concentration I've been conducting some experiments to determine the temperature dependence of a reaction. To do this, I've been conducting the experiments at different temperatures and generated a graph of$\ln{[\...
The irreversible liquid reaction $$\ce{A + B -> C + D}$$ follows an elementary rate law and is carried out isothermally in a plug flow reactor (PFR). The volume of the PFR is 500 litres....