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You are about to perform some intricate electrical studies on signal skeletal mu

ID: 619934 • Letter: Y

Question

You are about to perform some intricate electrical studies on signal skeletal muscle fibers from a gastronemius muscle. But first, you must prepare 6L of a 170 mM NaCL solution in which to bath the isolated muscle during your studies. How many grams of NaCL must you weigh out on the lab balance to prepare this bath solution? (html: the molecular weight of NaCL is 55.44 grams/mole). uL of 170 mM NaCL solution NaCL = 58.44 g/m g NaCL ? 170 times 10-3 = 0.17 moles 0.17 times 58.44 = 1L 0.17 times 58.44 times 6 = 59.61 grams A beaker contains 70 mL of water. How many molecules of water does this beaker comairt! (hint: the density of water is 1.0 g/mL) 70 mL of water What is the pH of solution with a hydrogen ion concentration of 9.4 times 10-7 mM? What is the hydrogen ion concentration of a solution with a pH of 8.5?

Explanation / Answer

volume=70ml 1 mole of water contains 6.023 x 10^23 molecules and since density of water is 1gram /1 ml weight of water = 70 grams

weight of 1 mole of water is 18 grams so number of molecules in 70 ml water is 70/18 x 6.023 x 10^23 = 23.422 x 10^23