CHEMICAL and contact can severely irritate and burn the skin and eyes leading to eye damage. What is the concentration of each species present in the following aqueous solutions? A balance and a volumetric flask are used to make molar solutions. If you want to prepare, say, 500 ml then take 14.025 g of KOH. A few drops of potassium hydroxide (KOH) are mixed with the sample. Measure 100ml of distilled water and add to the powder. Direct link to Hazelle R. Dela Cruz's post Assuming that you do not . The molecular weight of KOH is 56.1. Chapter 12.1: Preparing Solutions is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts. A KOH prep test is a simple, non-invasive procedure for diagnosing fungal infections of the skin or nails. Dissolve 12 g of KI in enough water to make 500 mL of solution. Yes, Jose. Sodium hydroxide is an ionic compound that is a strong electrolyte (and a strong base) in aqueous solution: B Because each formula unit of NaOH produces one Na+ ion and one OH ion, the concentration of each ion is the same as the concentration of NaOH: [Na+] = 0.21 M and [OH] = 0.21 M. A The formula (CH3)2CHOH represents 2-propanol (isopropyl alcohol) and contains the OH group, so it is an alcohol. How molarity is used to quantify the concentration of solute, and how to calculate molarity. Direct link to Dawen's post So this isn't quite the r, Posted 7 years ago. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. We can then use the molecular weight of sodium chloride. What is the normality of 10 NaOH? Your doctor may order a KOH exam if they suspect that a fungus could be the cause of your lesion. I was just wo, Posted 7 years ago. I believe you're correct. Step 3: Calculation of mass of hydrogen gas. 1) Calculate molarity of first solution (produced by dissolving 11.0 g of glucose): MV = grams / molar mass (x) (0.100 L) = 11.0 g / 180.155 g/mol x = 0.610585 mol/L (I'll carry a few guard digits.) Diluting a stock solution is preferred because the alternative method, weighing out tiny amounts of solute, is difficult to carry out with a high degree of accuracy. Contact can irritate the nose and throat. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. 1M HCl: Add 1mol/12M = 83 ml conc. ], [Why is the volume of the solution different from the volume of the solvent? So When 56 g of KOH is dissolved in 250mL water, a 4M solution of KOH is obtained. Dilution is also used to prepare solutions from substances that are sold as concentrated aqueous solutions, such as strong acids. Titrate with the ethanolic potassium hydroxide solution until a permanent pale pink color is produced. Molarity or molar concentration is the number of moles of solute per liter of solution, which can be calculated using the following equation: Molarity is a useful concept for stoichiometric calculations involving reactions in solution, such precipitation and neutralization reactions. Explanation: In order to solve this dilution, we must use the dilution equation, which states that M 1V 1 = M 2V 2. In that case, we can rearrange the molarity equation to solve for the moles of solute. Molarity of Potassium Hydroxide: 11.677 M, Molarity of Potassium Hydroxide: 11.677 M. Good, but you accidently put HCl in one of the blue arrows in the flow chart. Also, the number of moles of solute in 258 mL of the stock solution is the same as the number of moles in 2500 mL of the more dilute solution; only the amount of solvent has changed. Molar mass is the mass of 1 mole of the solute. If the amount of a substance required for a reaction is too small to be weighed accurately, the use of a solution of the substance, in which the solute is dispersed in a much larger mass of solvent, allows chemists to measure the quantity of the substance more accurately. Molarity of 37% (w/w) Hydrochloric Acid (HCl) , Protocol Plasmid Isolation by Alkaline Lysis Method (Miniprep), Preparation of 1M Potassium hydroxide from Concentrated Stock Solution (45%, w/w) - Laboratory Notes, Ammonium Acetate [CH3COONH4] Molecular Weight Calculation, Aluminum Sulfide [Al2S3] Molecular Weight Calculation, Aluminum Oxide [Al2O3] Molecular Weight Calculation, Aluminum Fluoride [AlF3] Molecular Weight Calculation, Aluminum Bromide [AlBr3] Molecular Weight Calculation, Aluminum Sulfate [Al2(SO4)3] Molecular Weight Calculation, Aluminum Hydroxide [Al(OH)3] Molecular Weight Calculation. Pipette 20.0 ml of 0.1 M hydrochloric acid into a flask. After the solid is completely dissolved, dilute the solution to a final volume with deionized (distilled) water. Modified by Joshua Halpern, Scott Sinex and Scott Johnson. Web. ; ; What volume of a 3.00 M glucose stock solution is necessary to prepare 2500 mL of the D5W solution in Example 4? Transfer the chemical to a screw-cap bottle. This cookie is set by GDPR Cookie Consent plugin. Let's consider the differences between these two similarly named chemical concepts: molarity and molality. How do you get mold out of grout without bleach? But wow, this app is amazing and actually solves equations with ease, but, ofc some of them is hard to understand and need to figure it out myself because of the pro limit, excelente app, pero sera ms completa si al resolver el problema que ponemos en la calculadora, nos diga qu tipo de problema, tipo de funcin . First, let's take a closer look at what is the mole, so we can move on later to find what is molarity. If a solution has a Ca(OCl)2 concentration of 3.4 g per 100 mL of solution, what is the molarity of hypochlorite? Procedure: Take a watch glass, wash it with distilled water and dry it. Formula used : where, = mass of solute KOH = ? Ideally 56.11g of KOH made up to 1L. Next, weigh out the solute and add it to a mixing beaker. There was likely a typographic error in the example. Check out 12 similar stoichiometry calculators , Determining the molar concentration by titration, Convert the expressions above to obtain a molarity formula. What are various methods available for deploying a Windows application? But if, say, the Pb(NO3)2 solution was twice the strength of the KI solution then you would only need 0.1 L of each to get the same number of moles. The volumes of two HCl solution A (0.5 N) and B (0.1 N) to be mixed for preparing 2 L of 0.2 N HCl are: Q. We can use the rearranged molarity equation to calculate the moles of. For preparing 60% KOH solution, you have to just Weigh 600 g pellets of KOH and dissolve in 1000 ml of distilled water (or, 60 g KOH pellets dissolved in 100 ml distilled water. 56.1056g/molPotassium hydroxide / Molar mass. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. If someone could maybe point me to a video/article on converting between concentration units, especially molarity to ppt or ppm, that'd be great. pH = 14 pOH = 14 1.48 = 12.52. HA reacts with KOH(aq) according to the following balanced chemical equation: HA(aq)+KOH(aq) KA(aq)+ H2O(l) 1st attempt Part 1 ( If 13.15 mL of 0.655MKOH is required to titrate the unknown acid to the equivalence point, what is the . I'm verifying the pH of the solution using a Thermofisher Orion Star A2216 pH sensor with ATC (automated temperature correction).. The subscript 1 stands for the initial conditions of a solution, while the subscript 2 stands for the final condition of the solution. Potassium Hydroxide (KOH) Solutions are used in a rapid method for distinguishing fungal elements in microscopic preparations. Water has a molarity of 55.5 M. 1 liter of water weighs 1000 g, and, as molarity is the number of moles per liter; finding the molarity of water is the same as finding the number of moles of water in 1000 g. We therefore divide the weight by the molar mass to get moles, 1000 / 18.02 = 55.5 M. Molarity is a helpful measure to use when discussing concentration. Then add about 200 mL of water. Note: 45% (w/w) Potassium Hydroxide means that 100 g of Potassium Hydroxide solution contains 45 g of KOH. (0.5 mol / 1000 mL) x 500 mL = 0.25 mol Molar mass of KOH = 56.11 g/mol Amount of KOH you need to weigh out = 0.25 mol x 56.11 g/mol = 14.028 g So, weigh out 14.028 g of KOH and transfer it to a 500 mL volumetric flask. However, the term molarity, also known as molar concentration, is the most common way of expressing the concentration. What experience do you need to become a teacher? As. A certain drug label carries instructions to add 10.0 mL of sterile water, stating that each milliliter of the resulting solution will contain 0.500 g of medication. Four different kinds of cryptocurrencies you should know. It is expressed in grams per mole. in hint one how do you know there is .1L of solute? How should the KOH solution be made? Cells are obtained from the affected area, placed on a slide with a solution consisting of potassium hydroxide, and examined under a microscope to look for signs of a fungus. 7 How do you prepare a solution of potassium hydroxide? Direct link to Anson Chan's post I was told in school that, Posted 7 years ago. Calculate the molar concentration of K+ ions in the 0 M solution. Molarity has many applications. Mixing together two or more reagents in order to get the necessary concentration of a certain chemical is required in order to carry out this method of solution preparation. We hope that after reading this paragraph, you will have no doubts regarding this topic. Formula: Density = weight / volume or Volume = weight / density or If we want to extremely precise, such as when making a standard solution for an analytical chemistry experiment, we would probably mix the solute and solvent in a. Learn how to calculate titrations in the titration calculator. Figure 12.1.4 Dissolution of 1 mol of an Ionic Compound In this case, dissolving 1 mol of (NH4)2Cr2O7 produces a solution that contains 1 mol of Cr2O72 ions and 2 mol of NH4+ ions. Occasionally, the number of elements may be quite high, or sometimes quite low, but as long as there is more than one element in an object, it is a mixture. on Molarity of 453 (w/w) Potassium Hydroxide (KOH). 189. it dissociates to produce a hydroxide ion. Chemists use many different units for describing concentration. Preparation of Solution. 575 L. 72 mol = 6 molL; Example 2: How many millilitres of concentrated H 2 SO 4 (16 M) is required to prepare 250 mL of 6 M H 2 SO 4 solution? To prepare 1000 mL of a 0.1 mol/L solution of Potassium hydroxide we have to dissolve 5.6105 g of KOH (100 % purity) in deionized or distilled water. A The D5W solution in Example 4 was 0.310 M glucose. It's used to caliberate the pH of the media. What is the molarity of the solution? M K 2 SO 4. Did you know that the human body is approximately. Convert 750 mL to liters. "Regulation (EC) No 1272/2008 Classification, packaging and labelling of chemicals and their mixtures." Weigh 10g of KOH powder and transfer to a flask. Determine molar mass: MM of NaOH = 40 g/mol. 0.1 L soln x 3 moles NaOH /1 L soln x 40 g NaOH/1 mole NaOH = 12 g NaOH. (b) The measured volume of stock solution is transferred to a second volumetric flask. Fruit drink is mostly sucrose (CHO), so you can assume that the "molar mass" of fruit drink is the same as the molar mass of sucrose. I understood what molarity is quite wellbut what is normality, formality and molarity? Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. So, in this video we are going to explain . It is just weight of salt/volume of distilled water. Complete the following table for 500 mL of solution. The purpose of the potassium hydroxide test (KOH test) is to identify gram negative bacteria. But to prepare solution of a given molarity, say to prepare 1 M KOH solution, you have to dissolve 56 g KOH (mol. now take 1 L water and dissolve 28.05 g KOH, youre done! It should be KOH. Remember that diluting a given quantity of stock solution with solvent does not change the number of moles of solute present. 45% (w/w) Potassium hydroxide solution contains 45 g of KOH per 100 g of Potassium hydroxide solution. so all you need to do is to decide how much (volume) of that you need. Mixtures are not limited to just liquids though, solids and gases can both be mixtures; even biological organisms are very complex mixtures of molecules, gases, and ions dissolved in water. Happy Learning. Weigh 20 g potassium hydroxide (KOH) pellets. C2 = concentration of acid which is required to be prepared. How can I prepare 500 ml of potassium iodide solution? Direct link to FoxFace's post I understood what molarit, Posted 6 years ago. No need to consider molecular weight of salt. Learn more in the solution dilution calculator. As well as for students who are into self study! For example, 1 mole of KOH is equal to 56.11 g of KOH (molecular weight = 56.11). Add the appropriate volume of 50 wt% NaOH solution to the 1 L bottle (you calculated this for the prelaboratory assignment). Dermatophytes or yeast seen on a KOH test indicate the person has a fungal infection. Another solution commonly used for intravenous injections is normal saline, a 0.16 M solution of sodium chloride in water. Hence, a 1M solution of NaCl contains 58. Prepare 800 mL of dH2O in a suitable container. If you continue to use this site we will assume that you are happy with it. {Date of access}. An experiment required 200.0 mL of a 0.330 M solution of Na2CrO4. How would you make 120 mL of a 0.10 M solution of potassium hydroxide? Second, calculate the amount of solute needed in grams, using one of the formulas given below. 4611 g/mol. Alternatively, you could start with concentrated KOH solution which can be purchased at 11.7 molar. When the reactants (compounds) are expressed in mole units, it allows them to be written with integers in chemical reactions. This should be done by providing the empirical chemical formula of the compound involved. Recall from Section 9.1 that alcohols are covalent compounds that dissolve in water to give solutions of neutral molecules. Calculate the volume of 4 M K 2 SO 4 that is needed to prepare 600. mL of a 0 M solution of K 2 SO 4. Explanation :- Let the required mass of KOH be x g. Molar mass of Potassium (K) = 39g/mol. Add approximately 50 ml of water (remember, not tap water) and three drops of methyl red indicator. 655.2 grams will be equal to = 655.2 x 1/56.11 = 11.677 moles. The proper procedure. Molarity = moles solute/Liter solution Molarity = 0.15 moles of KMnO 4 /0.75 L of solution Molarity = 0.20 M Inhaling Potassium Hydroxide can irritate the lungs. Add 101.1 grams of KNO3 to a small volume of water in a 1-Lvolumetric flask, dissolve the KNO3, and then fill the flask up to the 1 L mark with water. Direct link to tyersome's post With any luck, like most , Posted 3 years ago. It is possible to recalculate from molarity to molality and vice versa. A solution of a desired concentration can also be prepared by diluting a small volume of a more concentrated solution with additional solvent. A Classify each compound as either a strong electrolyte or a nonelectrolyte. Concentrations are usually expressed as molarity, the number of moles of solute in 1 L of solution. (c) The measured volume in the second flask is then diluted with solvent up to the volumetric mark [(Vs)(Ms) = (Vd)(Md)]. The relationship between the volume and concentration of the stock solution and the volume and concentration of the desired diluted solution is therefore, \((V_s)(M_s) = moles\: of\: solute = (V_d)(M_d)\tag{12.1.2}\). States of matter and intermolecular forces, [Is molar concentration the same as molality? Using a funnel, transfer oxalic acid softly and carefully from the watch glass into . When examining the equation for each of the percent solutions above, it is very important to note that in all cases the denominator refers to the solution mass or volume and not just the solvent mass or volume. Transfer the prepared solution to a clean, dry storage bottle and label it. First, determine the concentration (weight percent or Molarity, see below) and amount (milliliters) of solution you need from your lab procedure. Label the bottle and mark it . A 45% (w/w) concentrated Potassium hydroxide solution is a clear colorless liquid that can be purchased from several commercial suppliers. Would you expect a 1.0 M solution of CaCl2 to be a better conductor of electricity than a 1.0 M solution of NaCl? It follows that the molar mass of carbon-12 is exactly 12 grams per mole, M(C) = 12 g/mol. 8 How can I prepare 500 ml of potassium iodide solution? A 20.0-milliliter sample of .200-molar K2CO3 solution is added to 30.0 milliliters of .400-molar. Which of the representations shown in Problem 1 best corresponds to a 1 M aqueous solution of each compound? 12.5 x 100 Volume of H SO In chemistry, there are two types of mixtures: Homogeneous mixtures Components are uniformly distributed throughout the mixture, and there is only one phase of matter observed. In the discipline of cellular and molecular biology, one of the most important skills to have is the ability to prepare solutions. To log in and use all the features of Khan Academy, please enable JavaScript in your browser. wt. If a tablet containing 100 mg of caffeine (C8H10N4O2) is dissolved in water to give 10.0 oz of solution, what is the molar concentration of caffeine in the solution? Both terms are used to express the concentration of a solution, but there is a significant difference between them. Add 50 ml distilled water, and mix until the chemical is completely dissolved, add remaining distilled water and make the volume 100 ml. Make sure that the units for the volume are the same as for the volume part of the molarity (e.g., mL and mol/mL). These hydroxide ions act as a strong nucleophile and replace the halogen atom in an alkyl halide. This cookie is set by GDPR Cookie Consent plugin. The concentration of [ OH- ] can then be used to calculate the pOH of the solution. Click hereto get an answer to your question Calculate the amount of KOH required to prepare 100 mL of 0.1 M solution. Direct link to Abigail Baricevich's post How would you find the mo, Posted 5 years ago. Calculate the mass of sodium chloride needed to prepare 250 mL of normal saline solution. 2H2O is 165.87 g/mol. Cool and then dilute . Presence of EDTA in the solution results in sequestering of Mg2+. How do you find the molarity of potassium hydroxide? This cookie is set by GDPR Cookie Consent plugin. 0 M The acid number was calculated according to Equation (1). In this example we are going to make 1234 mL of a 1.54 molar solution of NaCl (Sodium chloride). Molar mass K H : Molar mass H 2 = mass K H: mass H 2. For example, consider the precipitation reaction that occurs between, Posted 7 years ago. 1 gram of KOH will be equal to 1/56.11 moles. Best for Showers: Home Armor Instant Mold and Mildew Stain Remover. Orange juice in your glass, a cup of tea, detergents in the bathroom or milk all these substances are mixtures. D.W. Green, R.H. Perry, "Densities of Aqueous Inorganic Solutions". In this molarity vs molality table, you can find all main differences between these two terms: Amount of substance (in moles) divided by the volume (in litres) of the solution. 0.01 N KOH solution can be prepared as follows. Follow the equation : S= n/V [S=molarity, n=moles, V= volume] This process is exothermic, so add KOH slowly. Thats the only way we can improve. To prepare 2.5 N KOH, you will need to dissolve 2.5 x 56.1 gm KOH (= 140.25 gm ) in less than a liter of water. Rearranging, n = CV = 0.50 0.25 = 0.125 mol We need 0.125 mol of KOH and the molar mass of KOH is 56.1 g mol1, so 56.1 0.125 = 7.0 g. We need 7.0 g of KOH. Solutions of known concentration can be prepared either by dissolving a known mass of solute in a solvent and diluting to a desired final volume or by diluting the appropriate volume of a more concentrated solution (a stock solution) to the desired final volume. For preparing 60% KOH solution, you have to just Weigh 600 g pellets of KOH and dissolve in 1000 ml of distilled water (or, 60 g KOH pellets dissolved in 100 ml distilled water. There must have been a typo. They are also known as solutions and may occur in the solid, liquid or gaseous state. Necessary cookies are absolutely essential for the website to function properly. how do you find the volume when given the mass and M value, We know that the formula to calculate the molarity of a substance is. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. It is not possible to simply separate the mixture components, but no chemical change has occurred to any of the components. Calculate how much lemonade powder you will need to make 0.100 L of each solution. This means a. For Question 2, I believe that the substance you are using as the base is the solvent. Concentration is a measure of how many moles of a substance are dissolved in an amount of liquid, and can have any volume units. Calculate the concentration of the new solution. HCl to 1L of water or . According to the newest conventions (effective as of the 20th May 2019), the mole definition is that a mole is the amount of a chemical substance that contains exactly 6.02214076 1023 particles, such as atoms, molecules, ions etc. Step 2: Calculate how many grams of Potassium hydroxide is present in 1000 ml of Potassium Hydroxide solution. Dissolve Tris base in 800 ml deionized/Milli-Q water using a magnetic stirrer. The beach is also surrounded by houses from a small town. 2) Calculate molarity of second solution (produced by diluting the first solution): M1V1= M2V2 (0.0200 L) (0.610585 mol/L) = (0.500 L) (x) How much K 2 Cr 2 O 7 is required to prepare 1 L of 0.1 N solution in acid medium. Stir the sodium hydroxide, a little at a time, into a large volume of water and then dilute the solution to make one liter. Yes, Jose. Molarity is the mass of solute in 1 L of solution: So, you would place 12 g of KI in a 500 mL volumetric flask and add enough water to dissolve the solid. To prepare a particular volume of a solution that contains a specified concentration of a solute, we first need to calculate the number of moles of solute in the desired volume of solution using the relationship shown in Equation 12.1.1. However, you may visit "Cookie Settings" to provide a controlled consent. Dissolve it in a 1L volumetric flask. In other words, molality is the number of moles of solute (dissolved material) per kilogram of solvent (where the solute is dissolved in). HEPES buffer (1 M HEPES-NaOH, pH 7.5) Recipe Created on Mar 21, 2013 Protocol details All protocols My protocols Add new protocol More FavoriteSign in to add to favorites. Solution: [NaBr] = 0. Mixtures with uniform composition are called, Mixtures with non-uniform composition are, The chemical in the mixture that is present in the largest amount is called the, In real life, we often encounter substances that are mixtures of different elements and compounds. Answered: What is the correct way to prepare a 1 Molarity is measued in moles per liter, mol L-1 , or molar, M , which means that a 0.500-M solution will contain 0.500 moles of potassium Do my homework now If substances are mixed together in such a way that the composition is the same throughout the sample, they are called, The component of a solution that is present in the largest amount is known as the, Let's consider a solution made by dissolving. The cookie is used to store the user consent for the cookies in the category "Analytics". KOH is an important chemical compound used in the tissue culture lab. Calculate the number of grams of solute in 1.000 L of each solution. Procedure to make 100 ml of KOH 20% w/v solution: Weigh 20 g potassium hydroxide (KOH) pellets. 1 ml of 0.1 M hydrochloric acid is equivalent to 0.00561 g of KOH. 1M KOH = 14 pH. This helps to easily work with their amounts. Like other ionic compounds, it is a strong electrolyte that dissociates in aqueous solution to give hydrated NH4+ and Cr2O72 ions: \( (NH_4 )_2 Cr_2 O_7 (s) \xrightarrow {H_2 O(l)} 2NH_4^+ (aq) + Cr_2 O_7^{2-} (aq)\tag{12.1.2} \). Pour a little bit into a spray bottle and spray it onto the contaminated area. Figure 12.1.3 Preparation of a Solution of Known Concentration by Diluting a Stock Solution (a) A volume (Vs) containing the desired moles of solute (Ms) is measured from a stock solution of known concentration. Add 16.282 g of Potassium phosphate dibasic to the solution. Molarity of 45% (w/w) Potassium Hydroxide (KOH). Molar mass is the mass of 1 mole of the solute. B If the compound is a nonelectrolyte, its concentration is the same as the molarity of the solution. Transfer the prepared solution to a clean, dry storage bottle and label it. 1 Answer. Why or why not? the in situ FTIR spectra of PtBi@6.7% Pb nanoplates recorded in Ar-saturated 1 M KOH + 1 M CH 3 OH solution. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. M stands for the molarity of a solution, while V stands for the volume of a solution. 10 N KOH (solution I) to 100 ml. In the table below, you can find the list of orders of magnitude for molar concentration, with examples taken from the natural environment. Add remaining distilled water and make the volume 100 ml. Here are the top grout cleaners to leave your grout looking better than ever. Stir the sodium hydroxide, a little at a time, into a large volume of water and then dilute the solution to make one liter. Example for reduced activity: DNA polymerases require Mg2+ for their activity. Pipette 20.0 ml of standardize 0.5 M hydrochloric acid into a flask. Phenol (C6H5OH) is often used as an antiseptic in mouthwashes and throat lozenges. A We must first calculate the number of moles of glucose contained in 500 mL of a 0.310 M solution: \( 500\: \cancel{mL} \left( \dfrac{1\: \cancel{L}} {1000\: \cancel{mL}} \right) \left( \dfrac{0 .310\: mol\: glucose} {1\: \cancel{L}} \right) = 0 .155\: mol\: glucose \). In that case, you can use the 1:1 formula because one mole of HCl reacts with one mole of NaOH. For acids, the number of equivalents per mole is the number of moles of hydrogen ions (H +) contributed to the reaction per mole of acid. More importantly, the molar ratio of Pt: Ag can greatly affect the size and morphology of porous PtAg nanoflowers. Definitions of solution, solute, and solvent. A balance and a volumetric flask are used to make molar solutions. Molar volume is the volume that one mole of a substance takes up at a particular temperature and pressure.