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3 years ago

What is meniscus ? why is it necessary to know about it when measuring liquids quizzlet?

Chemistry

2 answers:

love history [14]3 years ago

7 0

Answer:

Explained

Explanation:

The shape of the liquid surface when kept in a beaker or test tube, is called meniscus. A meniscus is of two types a convex or a concave meniscus. The downward bend of the surface is called convex meniscus like in mercury glass combination. Whereas the upward bend is called concave meniscus. Like in Water and glass combination. When mesuring liquids we must have an idea of meniscus to get the exact value of measurement.

AlekseyPX3 years ago

6 0

The downward or upward curve at the surface of liquid in a container is said to be the meniscus of the liquid, which occurs due to the surface tension. This curve can be concave or convex depending on how the molecules of liquid interact with surface of the container. The reading of the meniscus should always be done at the eye-level.

When the particles of the liquid are more attracted to the container than to each other then a concave meniscus occurs whereas when the particles of the liquid are more attracted to each other than to the container then a convex meniscus occurs.

The bottom of the curve will be read for a concave meniscus and for convex meniscus, the top of the curve gives the correct reading of the volume of liquid.

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3 years ago

In the Fischer esterification reaction, a carboxylic acid reacts with an excess of alcohol in acidic conditions to form an ester

Paul [167]

Answer:

See explanation and image attached

Explanation:

Esterification is a reaction of an alkanol and an alkanoic acid to yield an ester and water as products. It is analogous to inorganic neutralization reaction.

The process may be acid catalyzed. As mentioned in the question, the process of ester formation between pentanoic acid and n‑propanol first involves the carbonyl in going through an sp3 hybridized intermediate before returning to sp2 hybridized state in the product.

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4 0

3 years ago

When 100.g Mg3N2 reacts with 75.0 g H2O, what is the maximum theoretical yield of NH3?

Temka [501]

Answer : The correct option is, 23.6 g

Explanation : Given,

Mass of $Mg_3N_2$ = 100.0 g

Mass of $H_2O$ = 75.0 g

Molar mass of $Mg_3N_2$ = 101 g/mol

Molar mass of $H_2O$ = 18 g/mol

First we have to calculate the moles of $Mg_3N_2$ and $H_2O$ .

$\text{Moles of }Mg_3N_2=\frac{\text{Given mass }Mg_3N_2}{\text{Molar mass }Mg_3N_2}$

$\text{Moles of }Mg_3N_2=\frac{100.0g}{101g/mol}=0.990mol$

and,

$\text{Moles of }H_2O=\frac{\text{Given mass }H_2O}{\text{Molar mass }H_2O}$

$\text{Moles of }H_2O=\frac{75.0g}{18g/mol}=4.17mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

$Mg_3N_2(s)+6H_2O(l)\rightarrow 3Mg(OH)_2(aq)+2NH_3(g)$

From the balanced reaction we conclude that

As, 6 moles of $H_2O$ react with 1 mole of $Mg_3N_2$

So, 4.17 moles of $H_2O$ react with $\frac{4.17}{6}=0.695$ moles of $Mg_3N_2$

From this we conclude that, $Mg_3N_2$ is an excess reagent because the given moles are greater than the required moles and $H_2O$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NH_3$

From the reaction, we conclude that

As, 6 moles of $H_2O$ react to give 2 moles of $NH_3$

So, 4.17 moles of $H_2O$ react to give $\frac{2}{6}\times 4.17=1.39$ mole of $NH_3$

Now we have to calculate the mass of $NH_3$

$\text{ Mass of }NH_3=\text{ Moles of }NH_3\times \text{ Molar mass of }NH_3$

Molar mass of $NH_3$ = 17 g/mole

$\text{ Mass of }NH_3=(1.39moles)\times (17g/mole)=23.6g$

Therefore, the maximum theoretical yield of $NH_3$ is, 23.6 grams.

4 0

3 years ago

What did you have to look at it in order to correctly measure the amount of water in the graduated cylinder?

Zielflug [23.3K]

Answer:

Water sticks to the walls of the graduated cylinder, but only on the sides and not the middle. When students look at the surface, the water level is not straight.

Explanation:

meninges

meniscus

measles

metatarsle

6 0

3 years ago

Read 2 more answers

Select the most likely product for this reaction:

Jlenok [28]

Answer:

K2CO3(aq) + H2O(l)

Explanation:

Balance the equation

2KOH(aq) + CO2(g) ------ K2CO3(aq) + H2O(l)

7 0

3 years ago

Read 2 more answers