It stands for niobium which was discovered in 1801 by Charles Hatchett of Brittan. It is ussed in welding rods, air fraim systems, superconductive magnets. It gets its name from iobe, the daughter of King Tantalus of the Greek myth. Niobium was considered identical to Tantalum, named after Tantalus, until 1884. Resists corrosin due to an oxide film. It is used in aviation industry

4 0

3 years ago

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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.

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

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

Mo= 226.32/2 =113.16 g/mol

$M_n=X_nM_o$

Given that

Mn= 15,000 g/mol

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

4 years ago

what is the greatest amount of bread rolls that can be made with 6 cups of flour And 3 cups of water? If this were a chemical re

forsale [732]

Answer:

if you tell me how much is needed and how much you have then i can answer it, but there is not enough information provided to answer to that question.

Explanation:

7 0

3 years ago