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(1.) Using Beer's Law, How will the absorbance measured for the solutions change as the concentration of aspirin in solutions in

Vesnalui [34]

Answer:

(1) The absorbance of the aspirin in solutions will increase.

(2) [ASA]f = 3.79x10⁻⁴M

(3) [ASA]i = 3.79x10⁻³M

(4) m ASA = 0.171g

Explanation:

The Beer's Law is expressed by:

$A = \epsilon \cdot l \cdot C$ (1)

where A: is the absorbance of the species, ε: is the molar attenuation coefficient, l: is the pathlength and C: is the concentration of the species

(1) From equation (1), the relation between the absorbance of the species and its concentration is directly proportional, so if the aspirin concentration in solutions increases, the absorbance of the solutions will also increase.

(2) Starting in the given expression for the relationship between absorbance and concentration of ASA, we can calculate its concentration in the solution:

$A = 1061.5 \cdot [ASA]$

$[ASA] = \frac{A}{1061.5} = 3.79 \cdot 10^{-4}M$

Therefore, the aspirin concentration in the solution is 3.79x10⁻⁴ M

(3) To calculate the stock solution concentration, we can use the next equation:

$V_{i} [ASA]_{i} = V_{f} [ASA]_{f}$

where Vi: is the stock solution volume=10mL, Vf: is the solution diluted volume=100mL, [ASA]i: is the aspirin concentration of the stock solution and [ASA]f: is the aspirin concentration of the diluted solution

$[ASA]_{i} = \frac{V_{f} \cdot [ASA]_{f}}{V_{i}} = \frac {100mL \cdot 3.79\cdot 10^{-4} M}{10mL} = 3.79 \cdot 10^{-3} M$

Hence, the concentration of the stock solution is 3.79x10⁻³M

(4) To determine the aspirin mass in the tablet, we need to use the following equation:

$m_{ASA} = \eta_{ASA} \cdot M_{ASA} = [ASA]_{i} \cdot V_{0} \cdot M_{ASA}$

where η: is the aspirin moles = [ASA]i V₀, M: is the molar mass of aspirin=180.158g/mol, V₀: is the volume of the volumetric flask=250mL and [ASA]i: is the aspirin concentration in the volumetric flask which is equal to the stock solution=3.79x10⁻³M

$m_{ASA} = 3.79 \cdot 10^{-3} \frac{mol}{L} \cdot 0.250L \cdot 180.158 \frac{g}{mol} = 0.171 g$

Then, the aspirin mass in the tablet is 0.171 g.

I hope it helps you!

5 0

3 years ago

How many liters of CO2 are in 4.76 moles? (at STP)

dem82 [27]

Answer: The volume of carbon dioxide gas at STP for given amount is 106.624 L

Explanation:

We are given:

Moles of carbon dioxide = 4.76 moles

At STP:

1 mole of a gas occupies a volume of 22.4 Liters

So, for 4.76 moles of carbon dioxide gas will occupy a volume of = $\frac{22.4L}{1mol\times 4.76mol=106.624L$

Hence, the volume of carbon dioxide gas at STP for given amount is 106.624 L

6 0

3 years ago

PLEASE HELP BEFORE 7 A.M. PACIFIC TIME SEE ATTACHED.

anastassius [24]

For i: 33mL
For ii: 87-88mL
For iii:22.3mL

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3 years ago

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Which statement about gases is true?

Whitepunk [10]

Answer:

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What is the volume of an alka seltzer tablet

Delicious77 [7]

Answer:

Explanation:

Alka Seltzer tablet contains 325 mg of aspirin (acetylsalicylic acid), 1000 mg of citric acid, and 1916 mg of sodium bicarbonate. The acids originally contained in a tablet give only 17.4 mmol of H+, which is not enough to neutralize all of the sodium bicar- bonate (22.8 mmol).

3 0

3 years ago

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