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rosijanka [135]
2 years ago
13

How many variables are you allowed to change a purpose in a experiment

Chemistry
1 answer:
evablogger [386]2 years ago
4 0
Only one. variable to get a reliable results you only have to change one.
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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
Compute diffusion coefficients for the interdiffusion of carbon in both (a) α-iron (BCC) and (b) γ-iron (FCC) at 800.˚C. Assume
Ne4ueva [31]

Answer:

a)1.404 E-10 m^2/s

b)1.438 E-12 m^2/s

Explanation:

Diffusion Coefficients can be calculated at different temperatures taking into account the energy of the diffusive process, remember that this process takes place in the interstices of the solid, and gets with higher temperatures due to the higher kinetic energy of the particles.

D=D_{o} *exp(-Q/RT)

a) For α-iron (BCC)

D=1.10*10^{-6} m^{2}/s *exp(-80.0kJ/mol/8.314*10^{-3}kJ/mol*k*1073.15K)= 1.404*10^{-10} m^{2}/s

b) For γ-iron (FCC)

D=2.30*10^{-5} m^{2}/s *exp(-148.0kJ/mol/8.314*10^{-3}kJ/mol*k*1073.15K)= 1.438*10^{-12} m^{2}/s

5 0
3 years ago
Why do boys my age not like me ?
enyata [817]

Answer:

Because boys are overrated

Explanation:

8 0
3 years ago
Read 2 more answers
GIVE THE DEFINITION OF EACH WORD.
KATRIN_1 [288]

1. a group of resources treated as a single entity that accepts a combination of materials and instructions to add value through a series of operations; may be either automated or manual.

2. a group of cells that have similar structure and that function together as a unit. A nonliving material, called the intercellular matrix, fills the spaces between the cells.

3. a differentiated structure (such as a heart, kidney, leaf, or stem) consisting of cells and tissues and performing some specific function in an organism.

4. a group of organs that work together to perform a certain function in an organism's body.

5.  complex systems of chemical compounds that, through interaction and environment, play a wide variety of roles. Organisms are semi-closed chemical systems. Although they are individual units of life (as the definition requires), they are not closed to the environment around them.

6. the significance of the charge hosted by a particular atom in a molecule becomes obvious

7. an interacting group of various species in a common location

8. an ecological community comprised of biological, physical, and chemical components

9. the variety of life found in a place on Earth

7 0
2 years ago
Which of the following do you expect to have soil with the highest fertility
Andrej [43]
It would help if I could see the specific answer choices, but an environment that would have lots of oxygen, water, decaying organisms and sunlight would be the answer (ex. the forest or riverbed)
7 0
3 years ago
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