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ipn [44]
3 years ago
14

sodium-25 was to be used in an experiment but it took 3.0 minutes to get the sodium from the reactor to the laboratory if 5.0 mg

of sodium-25 was removed from the reactor how many mg of sodium-25 were placed in the reaction vessel 3.0 minutes later if the half-life of sodium-25 is 60 seconds
Chemistry
1 answer:
Hoochie [10]3 years ago
7 0
3 half lives later... 5/2 = 2.5mg, then 2.5/2 = 1.25 mg, then 1.25/2 = .625 mg left
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To calculate the number of moles of gas remaining in his after he exhale, we'll have to use Avogadro's law which states that the volume of a given mass of gas is directly proportional to its number of moles provided that temperature and pressure are kept constant. Mathematically,

V = kN, k = V / N

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From the above equation,

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The number of moles of gas in his lungs when he exhale is 0.053 moles

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We need to measure 20.0 grams of CaCl₂ to prepare 500 mL of 0.360 M solution.

First, we need to determine the required moles of CaCl₂. We have 500 mL (0.500 L) of a 0.360 M solution (0.360 moles of CaCl₂ per liter of solution).

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Then, we will convert 0.180 moles to grams using the molar mass of CaCl₂ (110.98 g/mol).

0.180 mol \times \frac{110.98g}{mol} = 20.0 g

To prepare the solution, we weigh 20.0 g of CaCl₂ and add it to a beaker with enough distilled water to dissolve it. We stir it, heat it if necessary, and when we have a solution, we transfer it to a 500 mL flask and complete it to the mark with distilled water.

We need to measure 20.0 grams of CaCl₂ to prepare 500 mL of 0.360 M solution.

You can learn more about solutions here: brainly.com/question/2412491

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