Ask question

Ask question

All categories

3 years ago

12

What is the molarity of a solution made by dissolving 21.2 g of sodium hydroxide (NaOH) in enough water to make 7.92 L of soluti

on?
Molar Mass Na: 22.99 g/mol
Molar Mass O: 16.00 g/mol
Molar Mass H: 1.008 g/mol

2 answers:

g100num [7]3 years ago

6 0

M = mol/L so add all molar masses together then divide 21.2g/(molar mass) then divide by Litres

Triss [41]3 years ago

5 0

Hey there!

Attached resolution .

You might be interested in

Which of the following ions is in the lowest oxidation state?

bulgar [2K]

Answer:

I believe it is a hope this helps

5 0

3 years ago

Read 2 more answers

Calculate the feed ratio of adipic acid and hexamethylene diamine that should be employed to obtain a polyamide of approximately

artcher [175]

Answer:

r= 0.9949 (For 15,000)

r=0.995 (For 19,000)

Explanation:

We know that

Molecular weight of hexamethylene diamine = 116.21 g/mol

Molecular weight of adipic acid = 146.14 g/mol

Molecular weight of water = 18.016 g/mol

As we know that when adipic acid and hexamethylene diamine react then nylon 6, 6 comes out as the final product and release 2 molecule of water.

So

$M_{repeat}=146.14+166.21-2\times 18.106\ g/mol$

$M_{repeat}=226.32\ g/mol$

So

Mo= 226.32/2 =113.16 g/mol

$M_n=X_nM_o$

Given that

Mn= 15,000 g/mol

So

15,000 = Xn x 113.16

Xn = 132.55

Now by using Carothers equation we know that

$X_n=\dfrac{1+r}{1+r-2rp}$

$132.55=\dfrac{1+r}{1+r-2\times 0.99r}$

By calculating we get

r= 0.9949

For 19,000

19,000 = Xn x 113.16

Xn = 167.99

By calculating in same process given above we get

r=0.995

3 0

3 years ago

What is the vapor pressure of the solution if 35.0 g of water is dissolved in 100.0 g of ethyl alcohol at 25 ∘C? The vapor press

masya89 [10]

<u>Answer:</u> The vapor pressure of the solution is 43.55 mmHg

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

<u>For water:</u>

Given mass of water = 35.0 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{35.0g}{18g/mol}=1.944mol$

<u>For ethyl alcohol:</u>

Given mass of ethyl alcohol = 100.0 g

Molar mass of ethyl alcohol = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of ethyl alcohol}=\frac{100.0g}{46g/mol}=2.174mol$

Total moles of solution = [1.944 = 2.174] moles = 4.118 moles

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

<u>For water:</u>

$\chi_{\text{water}}=\frac{n_{\text{water}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{water}=\frac{1.944}{4.118}=0.472$

<u>For ethyl alcohol:</u>

$\chi_{\text{ethyl alcohol}}=\frac{n_{\text{ethyl alcohol}}}{n_{\text{water}}+n_{\text{ethyl alcohol}}}$

$\chi_{\text{ethyl alcohol}}=\frac{2.174}{4.118}=0.528$

Dalton's law of partial pressure states that the total pressure of the system is equal to the sum of partial pressure of each component present in it.

To calculate the vapor pressure of the solution, we use the law given by Dalton, which is:

$P_T=\sum_{i=1}^n (p_i\times \chi_i)$

Or,

$P_T=[(p_{\text{water}}\times \chi_{\text{water}})+(p_{\text{ethyl alcohol}}\times \chi_{\text{ethyl alcohol}}$

We are given:

Vapor pressure of water = 23.8 mmHg

Vapor pressure of ethyl alcohol = 61.2 mmHg

Putting values in above equation, we get:

$p_T=[(23.8\times 0.472)+(61.2\times 0.528)]\\\\p_T=43.55mmHg$

Hence, the vapor pressure of the solution is 43.55 mmHg

4 0

3 years ago

What are the masses of the four different BrClBrCl molecules? Express the masses in atomic mass units using six significant figu

Sliva [168]

Answer ; The question is missing in some details, but here are he details ;

The two naturally occurring isotopes of bromine are

81Br (80.916 amu, 49.31%) and

79Br (78.918 amu, 50.69%).

The two naturally occurring isotopes of chlorine are

37Cl (36.966 amu, 24.23%) and

35Cl (34.969 amu, 75.77%).

Bromine and chlorine combine to form bromine monochloride, BrCl.

Explanation:

The detaile calculation is as shown in the attachment.

6 0

3 years ago

Who created the planetary model of the atom?

shtirl [24]

The answer is Rutherford.

4 0

2 years ago