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3 years ago

A mothball, composed of naphthalene (c10h8), has a mass of 1.64 g . part a how many naphthalene molecules does it contain?

1 answer:

3 0

The molar mass of Naphthalene is 128g/mol
Therefore; a mass of 1.64 g of Naphthalene contains'
= 1.64g/128 g
= 0.0128 moles
But, from the Avogadro's law 1 mole of a substance contains 6.022 × 10^23 particles
Therefore 1 mole of Naphthalene contains 6.022×10^23 molecules
Hence; 0.0128 moles × 6.022 ×10^23 molecules
= 7.716 × 10^21 molecules

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According to Bowen's reaction series, crystal settling should result in the magma being separated in lower layers rich in the ea

monitta

Answer:

quartz and olivine

Explanation:

According to my research on studies made by different geologists on Bowen's reaction series, it is known that crystal settling should result in the magma being separated in lower layers rich in the early-formed quartz and olivine minerals.

I hope this answered your question. If you have any more questions feel free to ask away at Brainly.

6 0

4 years ago

Rosa eats peanut butter sandwich for lunch. Peanut butter contains a lot of proteins, and bread is mostly starch. Rosa plan to g

Gemiola [76]

Answer:

Explanation:

This question comprises a couple of questions that are interwoven. However, the description below should suffice.

The part of the food she needs to go for the run is bread (starch) while the component of the air she requires is oxygen. This is because starch are polymers that are made of glucose monomers which are known sources of energy for the body. Air contains nitrogen, oxygen, carbon dioxide and rare gases; the oxygen from air here is necessary for many metabolic activities in the body during the race.

Her respiratory and her digestive system work together to provide her with the molecules (mainly oxygen and glucose) that she needs in her cells. The digestion of starch is a multienzyme process that is summarized as follows. The digestion of the starch (bread) begins in the mouth. The bread is acted upon by the enzyme amylase which is present in the saliva. The enzyme breaks down this starch into small glucose chains and then to dextrins and maltose (which is a disaccharide). The disaccharide is then broken down into glucose. Only a small fraction of the starch is broken down to glucose in the mouth. The broken and unbroken food substance is then taken to the stomach where little activity occur because of the acidic condition but the process continues/accelerates in the small intestine until alot of glucose is produced from the food (bread). The oxygen taken in through the respiratory system is then transported through the circulatory system to various parts of the body. The glucose molecules produced by the breakdown of starch is also diffuses into blood stream and taken up by various cells in the body.

The cells in her body convert these glucose to energy (ATP) through the process known as glycolysis (breakdown of glucose). This energy is what is released from her cells and then used to run.

3 0

3 years ago

If 500.0 ml of 0.10 m ca2+ is mixed with 500.0 ml of 0.10 m so42−, what mass of calcium sulfate will precipitate? ksp for caso4

attashe74 [19]

Answer : The mass of calcium sulfate precipitate will be, 6.12 grams

Solution :

First we have to calculate the moles of $Ca^{2+}$ and $SO_4^{2-}$ .

$\text{Moles of }Ca^{2+}=\text{Molarity of }Ca^{2+}\times \text{Volume of }Ca^{2+}=0.10mole/L\times 0.5L=0.05\text{ moles}$

$\text{Moles of }SO_4^{2-}=\text{Molarity of }SO_4^{2-}\times \text{Volume of }SO_4^{2-}=0.10mole/L\times 0.5L=0.05\text{ moles}$

As, 0.05 moles of $Ca^{2+}$ is mixed with 0.05 moles of $SO_4^{2-}$ , it gives 0.05 moles of calcium sulfate.

Now we have to calculate the solubility of calcium sulfate.

The balanced equilibrium reaction will be,

$CaSO_4\rightleftharpoons Ca^{2+}+SO_4^{2-}$

The expression for solubility constant for this reaction will be,

$K_{sp}=(s)\times (s)$

$K_{sp}=(s)^2$

Now put the value of $K_{sp}$ in this expression, we get the solubility of calcium sulfate.

$2.40\times 10^{-5}=(s)^2$

$s=4.89\times 10^{-3}M$

Now we have to calculate the moles of dissolved calcium sulfate in one liter solution.

$\text{Moles of }CaSO_4=\text{Molarity of }CaSO_4\times \text{Volume of }CaSO_4=4.89\times 10^{-3}mole/L\times 1L=4.89\times 10^{-3}\text{ moles}$

Now we have to calculate the moles of calcium sulfate that precipitated.

$\text{Moles of }CaSO_4\text{ precipitated}=\text{Moles of }CaSO_4\text{ present}-\text{Moles of }CaSO_4\text{ dissolved}$

$\text{Moles of }CaSO_4\text{ precipitated}=0.05-4.89\times 10^{-3}=0.045\text{ moles}$

Now we have to calculate the mass of calcium sulfate that precipitated.

$\text{Mass of }CaSO_4\text{ precipitated}=\text{Moles of }CaSO_4\text{ precipitated}\times \text{Molar mass of }CaSO_4$

$\text{Mass of }CaSO_4\text{ precipitated}=0.045moles\times 136g/mole=6.12g$

Therefore, the mass of calcium sulfate precipitate will be, 6.12 grams

5 0

3 years ago

Read 2 more answers

What is tins atomic symbol

qaws [65]

Tin
Chemical Element
Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Wikipedia
Symbol: Sn
Electron configuration: [Kr] 4d105s25p2
Atomic number: 50
Melting point: 449.5°F (231.9°C)
Atomic mass: 118.71 u
Boiling point: 4,717°F (2,603°C)
Electrons per shell: 2, 8, 18, 18, 4

4 0

4 years ago

Read 2 more answers

A person suspects that an unknown liquid is water. he adds 110.0 J of heat to 55.0 g of liquid. The temperature of the liquid in

Tema [17]

Explanation:

First thing first, you mistyped the specific heat of water, which should be

water

4.18

∘

Now, a substance's specific heat tells you how much heat is required to increase the temperature of

1 g

of that substance by

∘

In the case of water, you would need

4.18 J

to increase the temperature of

1 g

of water by

∘

Notice that your sample of water has a mass of

1 g

as well, which means that the only factor that will determine the amount of heat needed will be the difference in temperature.

The equation that establishes a relationshop between heat and change in temperature looks like this

⋅

, where

- heat absorbed

- the specific heat of the substance, in your case of water

- the change in temperature, defined as the difference between the final temperature and the initial temperature

Plug in your values and solve for

to get

1.00

⋅

4.18

⋅

∘

⋅

(

83.7

−

26.5

)

∘

239.096 J

Rounded to three sig figs, the answer will be

239 J

5 0

3 years ago