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3 years ago

True or False: It is OK to use wet glassware for the aspirin synthesis without potentially affecting your yield

Chemistry

1 answer:

vesna_86 [32]3 years ago

5 0

Answer:

False

Explanation:

Laboratory synthesis of aspirin is done by the acetylation of salicylic acid with the help of acetic anhydride .

As , the acid anhydride is very sensitive to moisture , as it can hydrolyze into two molecules of acids,

Hence , the reaction involving acid anhydride are conducted in anhydrous solvents .

Hence ,

if water is present in the glassware then , some of the acetic anhydride is wasted , Which in turns reduces the yield than that expected .

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Use the following information S(s)+O2(g)→SO2(g), ΔH∘ = -296.8kJ SO2(g)+12O2(g)→SO3(g) , ΔH∘ = -98.9kJ to calculate ΔH∘f for H2SO

Irina-Kira [14]

Answer : The enthalpy of formation of $H_2SO_4$ is, -812.4 kJ/mole

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The formation of $H_2SO_4$ will be,

$S+H_2+2O_2\rightarrow H_2SO_4$ $\Delta H_{formation}=?$

The intermediate balanced chemical reaction will be,

(1) $S+O_2\rightarrow SO_2$ $\Delta H_1=-298.2$

(2) $SO_2+\frac{1}{2}O_2\rightarrow SO_3$ $\Delta H_2=-98.2$

(3) $SO_3+H_2O\rightarrow H_2SO_4$ $\Delta H_3=-130.2$

(4) $H_2+\frac{1}{2}O_2\rightarrow H_2O$ $\Delta H_4=-285.8$

Now adding all the equations, we get the expression for enthalpy of formation of $H_2SO_4$ will be,

$\Delta H_{formation}=\Delta H_1+\Delta H_2+\Delta H_3+\Delta H_4$

$\Delta H=(-298.2)+(-98.2)+(-130.2)+(-285.8)$

$\Delta H=-812.4kJ/mol$

Therefore, the enthalpy of formation of $H_2SO_4$ is, -812.4 kJ/mole

3 0

3 years ago

Graph the circle which is centered at (4,4)(4,4)left parenthesis, 4, comma, 4, right parenthesis and has a radius of 3 units.

OleMash [197]

Answer:

i dont know the answer sorry

7 0

2 years ago

What is the initial temperature (°C) of a system that has the pressure decreased by 10 times while the volume increased by 5 tim

Ede4ka [16]

Answer:

300K

Explanation:

Given pressure of the system decreased by 10 times which means $P_{2} =\frac{P_{1} }{10}$

Given the volume of the system increased by 5 times which means $V_{2} =5\times V_{1}$

Given final temperature $T_{2}=150K$

Let the initial temperature be $T_{1}$

We know that PV=nRT

As n and R are constant $\frac{PV}{T}=constant$

$\frac{P_{1}V_{1} }{T_{1}} =\frac{P_{2}V_{2}}{T_{2}}$

$T_{1} =\frac{P_1V_1}{P_2V_2} T_{2}$

$T_{1} =2\times T_{2}$

T1=300K

8 0

2 years ago

Devise a way to separate sand from a mixture of charcoal, sand, sugar, and water

madreJ [45]

A mixture of charcoal, sand, sugar, and water is a heterogeneous mixture. Sugar can easily dissolve in water. Slightly heating the mixture will ensure all of the sugar is dissolved in the water. The mixture then can be filtered to separate out sugar solution from sand and charcoal. The mixture of sand and charcoal is washed several times with water and filtered so that no traces of sugar solution remain in the mixture. To the mixture containing sand and charcoal, water is added. Charcoal being lighter floats on the surface of water, whereas sand being heavy sinks to the bottom. The charcoal floating can be removed manually. After all the charcoal is removed, the mixture of sand and water is again filtered and the sand collected on filter paper is dried. Therefore, by using the above process sand can be separated out from a mixture of charcoal, sand, sugar, and water.

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2 years ago

The stability of atomic nuclei seem to be related to the ratio of _____.

Andru [333]

<span>Neutrons to protons. Neutrons and protons are tiny particles that are within the nucleus. Neutrons and protons make up the nucleus of the cell and the ratio of neutrons determine the stability of the atomic nuclei. The nucleus will become unstable if the ratio of neutrons to protons are not within the appropriate amount.</span>

6 0

3 years ago

Read 2 more answers