HS IB Science teacher. IB Chemistry on Mole Concept. Research question and IA Assessment rubric. Stoichiometric Calculations. Related Books Free with a 30 day trial from Scribd. Dry: A Memoir Augusten Burroughs.
Related Audiobooks Free with a 30 day trial from Scribd. Empath Up! Cal vol in dm3 of 0. Cal its molarity. Cal molarity of KOH when cm3 water added to cm3 , 0. Prepare cm3 , 0. What vol of conc acid must be diluted. Shelby Green Dec. LindaWilson69 Sep. MayursinhGohil1 Aug. Sandeep Dixit May. Show More.
Total views. You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips. Visibility Others can see my Clipboard. Cancel Save. Very often you will need to make a specific volume of known concentration from stock solutions, or perhaps due to limited availability of liquid materials some chemicals are very expensive and are only sold and used in small quantities, e.
The formula below is a quick approach to calculating such dilutions where:. You need to know what volume V 1 of the stock to use as part of the ul total volume needed. This is your unknown. So, you would take 0. Remember that the amount of solvent used is based upon the final volume needed, so you have to subtract the starting volume form the final to calculate it.
Sometimes it may be more efficient to use molarity when expressing chemical concentrations. A mole is defined as exactly 6. The mass of one mole of an element is its atomic mass g and is noted for each element in the periodic table.
Molecular weight is the mass g of a substance based on the summed atomic masses of the elements in the chemical formula. The formula weight of 1 mole NaCl would therefore be the sum of 1 atomic mass of each ion. The molecular weight or FW is provided as part of the information on the label of a chemical bottle. The number of moles in an arbitrary mass of an element or compound can be calculated as:. By this definition, a 1. Example 1: To prepare a liter of a molar solution from a dry reagent.
Multiply the molecular weight or FW by the desired molarity to determine how many grams of reagent to use:. You would dissolve the specified mass of reagent in a fraction of the total volume of solvent at STP and then raise the volume to exactly one liter by adding additional solvent and mixing thoroughly.
Example 2 : To prepare a specific volume of a specific molar solution from a dry reagent. How many grams of the chemical are needed to make this solution?
Complex solutions such as buffers, salines, fixatives, etc. In preparation of these solutions, each reagent is dealt with separately in determining how much to use to make the final solution. For each, the volume used in the calculations is the final volume of solution needed. More examples of worked problems: About. Top of page. When preparing solutions from dry reagents, the same mass of any reagent is used to make a given percent concentration although the molar concentrations would be different.
Example 1 : Convert a 6. To convert from molarity to percent solution , multiply the molarity by the FW and divide by
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