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158 solutions

Molarity

Q. A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 525 mL of a solution that has a concentration of Na+ ions 1.40 M? Express your answer numerically in grams.

Solved • Feb 17, 2020

Molarity

Q. The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood. Luminol has a molecular weight of 177 g/mol. The forensic technician at a crime scene has just prepared a luminol stock solution by adding 18.0 g of luminol to H2O creating a solution with a total volume of 75.0 mL. What is the molarity of the stock solution of luminol?

Solved • Feb 17, 2020

Molarity

Q. The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood. Luminol has a molecular weight of 177 g/mol. Before investigating the scene, the technician must dilute the luminol solution to a concentration of 5.00 x 10^-2 M. The dilute solution is then placed in a spray bottle for application on the desired surfaces. How many moles of luminol are present in 2.00 L of the diluted spray?

Solved • Feb 17, 2020

Molarity

Q. Calculate the molarity of S2O82− if 2.0 mL 0.10 M K2S2O8, 3.0 mL 0.10 M K2SO4, 1.0 mL 2% starch, 2.0 mL 0.010 M Na2S2O3, and 5.0 mL 0.20 M KI are mixed.

Solved • Feb 17, 2020

Molarity

Q. A medical lab is testing a new anticancer drug on cancer cells. The drug stock solution concentration is 1.5×10−9M, and 3.00 mL of this solution will be delivered to a dish containing 2.0×105 cancer cells in 5.00 mL of aqueous fluid. What is the ratio of drug molecules to the number of cancer cells in the dish?

Solved • Feb 12, 2020

Molarity

Q. Molarity (M) is a unit of concentration which tells us how much of a substance is present in a liter of a solution. 1.0 mL of a 0.10 M solution will contain 1.0 x 10-4 moles of the substance. How much will 1.0 x 10-4 moles of each of the following compounds weigh? 1.) Barium nitrate 2.) Calcium nitrate 3.) Magnesium nitrate 4.) Strontium nitrate

Solved • Feb 7, 2020

Molarity

Q. The density of toluene (C7H8) is 0.867 g.mL, and the density of thiophene (C4H4S) is 0.065 g/mL. A solution is made by dissolving 8.10 g of thiophene in 270 mL of toluene. Assuming that the volumes of the solute and solvent are additive, what is the molarity of thiophene in the solution?

Solved • Feb 7, 2020