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Help please with question number 16)

Zanzabum

Answer:

Mg²⁵ = 10.00%

Mg²⁶ = 45.04%

Mg²⁴ = 44.96%

Explanation:

Given data:

Atomic mass of Mg²⁶ = 25.983

Atomic mass of Mg²⁵ = 24.986

Atomic mass of Mg²⁴ = 23.985

Abundance of Mg²⁵ = 10.00%

Abundance of Mg²⁶ = ?

Abundance of Mg²⁴ = ?

Solution:

Average atomic weight of Mg = 25.983 + 24.986+ 23.985 / 3

Average atomic weight of Mg = 74.954/3

Average atomic weight of Mg = 24.985 amu

Abundance of

Mg²⁵ = 10.00

Mg²⁶ = x

Mg²⁴ = 100- 10 - x = 90 -x

Formula:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100

24.985 = (0.1×24.986)+(90-x×23.985) + ( x ×25.983 ) /100

24.985 = 249.86 + 2158.65 - 23.985x + 25.983x / 100

24.985 = 2408.51 + 1.998 x / 100

2498.5 = 2408.51 + 1.998 x

1.998 x = 2498.5 - 2408.51

1.998 x = 89.99

x = 89.99 /1.998

x = 45.04

Now we put the value of x:

Mg²⁵ = 10.00

Mg²⁶ = x (45.04)

Mg²⁴ = 90 -x (90 - 45.04 = 44.96)

5 0

3 years ago

Consider the nitration by electrophilic aromatic substitution of salicylamide to iodosalicylamide. Reaction scheme illustrating

kvv77 [185]

<u>Answer:</u> The percent yield of the reaction is 68.68%.

<u>Explanation:</u>

To calculate the mass of salicylamide, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of salicylamide = 1.06 g/mL

Volume of salicylamide = 3.65 mL

Putting values in above equation, we get:

$1.06g/mL=\frac{\text{Mass of salicylamide}}{3.65mL}\\\\\text{Mass of salicylamide}=(1.06g/mL\times 3.65mL)=3.869g$

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

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

Given mass of salicylamide = 3.869 g

Molar mass of salicylamide = 137.14 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylamide}=\frac{3.869g}{137.14g/mol}=0.0295mol$

The chemical equation for the conversion of salicylamide to iodo-salicylamide follows:

$\text{salicylamide }+NaI+NaOCl+EtOH\rightarrow \text{iodo-salicylamide }$

By Stoichiometry of the reaction:

1 mole of salicylamide produces 1 mole of iodo-salicylamide

So, 0.0295 moles of salicylamide will produce = $\frac{1}{1}\times 0.0295=0.0295moles$ of iodo-salicylamide

Now, calculating the mass of iodo-salicylamide from equation 1, we get:

Molar mass of iodo-salicylamide = 263 g/mol

Moles of iodo-salicylamide = 0.0295 moles

Putting values in equation 1, we get:

$0.0295mol=\frac{\text{Mass of iodo-salicylamide}}{263g/mol}\\\\\text{Mass of iodo-salicylamide}=(0.0295mol\times 263g/mol)=7.76g$

To calculate the percentage yield of iodo-salicylamide, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of iodo-salicylamide = 5.33 g

Theoretical yield of iodo-salicylamide = 7.76 g

Putting values in above equation, we get:

$\%\text{ yield of iodo-salicylamide}=\frac{5.33g}{7.76g}\times 100\\\\\% \text{yield of iodo-salicylamide}=68.68\%$

Hence, the percent yield of the reaction is 68.68%.

4 0

3 years ago

A farm is located on the edge of a river. The farmer has an insect problem and doubles the amount of pesticides used for several

lora16 [44]

Pollution would go in the form of surface runoff and into rivers and ocean and then disrupt ecosystems because some ecosystems depend on water

7 0

3 years ago

Read 2 more answers

If you have 25 pieces of bread and 9 pieces of turkey and a turkey

Varvara68 [4.7K]

The turkey limits bc you can make 9 sandwiches with 9 turkey and 12 sandwiches with 25 bread

3 0

3 years ago

7. A gas ______.

enot [183]

Answer:

C

Explanation:

A gas is a state of matter that has no fixed shape and no fixed volume gases have lower density than other states of matter such as solids and liquids.

7 0

3 years ago