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vredina [299]
4 years ago
10

What structure do insects have for breathing (A) gills (B) tracheae (C) skin (D) lungs

Chemistry
1 answer:
den301095 [7]4 years ago
7 0
I believe tracheae!!!!
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Complete the equations showing how 2−phenylethanol (c6h5ch2ch2oh) could be prepared from 2−phenylethanoic acid (c6h5ch2co2h) as
avanturin [10]
We are asked to provide an equation for the transformation of 2-phenylethanoic acid to 2-phenylethanol. This type of a reaction is converting a carboxylic acid to an alcohol, which is classified as a reduction reaction since we are decreasing the number of bonds to oxygen in the molecule. In order to reduce a carbonyl to an alcohol, we need a source of hydride, H⁻. Reducing the carboxylic acid once will convert it to the aldehyde. However, we need to reduce the functional group all the way down to an alcohol, which is another reduction step after aldehyde formation. Therefore, the hydride source of choice is lithium aluminum hydride, LiAlH₄.

A reaction scheme is provided to show the reaction of the reduction of carboxylic acid to alcohol. The first step is addition of lithium aluminum hydride which does the reduction, and the second step is a work-up of acid which protonates the alcohol to get the final product.

7 0
3 years ago
Question 25 of 25
mrs_skeptik [129]

Answer:

D. 37 reports

Explanation:

Last month, he wrote 9 reports, and this month he wrote 28 reports. To find how many he wrote over the past two months, add his reports from last month and this month.

last month + this month

9 reports +28 reports

37 reports

So, he wrote 37 reports, or choice D

5 0
3 years ago
when 42.66 grams of PCl5 react with excess P4O10 the amount of product formed is 47.22 grams of POCl3. What is the percent yield
icang [17]

Percent yield or yield is mathematically defined as:

Yield = Actual amount / Theoretical amount

So to solve the yield, let us first calculate the theoretical amount of POCl3 produced. The balanced chemical reaction for this is:

6 PCl5 + P4O10  --->  10 POCl3

Since P4O10 is stated to be supplied in large amount, then PCl5 becomes the limiting reactant.

So we calculate for POCl3 based on PCl5. To do this let us convert the amount into moles: (molar mass PCl5 = 208.24 g/mol)

n PCl5 = 42.66 grams / (208.24 g/mol)

n PCl5 = 0.205 mol

 

Now based on the stoichiometric ratio of the reaction:

<span>n POCl3 = 0.205 mol (10 POCl3 / 6 PCl5)
n POCl3 = 0.3414 mol POCl3</span>

Converting to mass (molar mass POCl3 = 153.33 g/mol)

m POCl3 = 0.3414 mol (153.33 g/mol)

m POCl3 = 52.35 g

 

Calculating for yield:

Yield = 47.22 g/ 52.35 g

Yield = 0.902

<span>%Yield = 90.2 %                      (ANSWER)</span>

6 0
3 years ago
A sample of vinegar was found to have an acetic acid concentration of 0.8846 m. What is the acetic acid % by mass? Assume the de
jenyasd209 [6]

Answer:

5.3%

Explanation:

Let the volume be 1 L

volume , V = 1 L

use:

number of mol,

n = Molarity * Volume

= 0.8846*1

= 0.8846 mol

Molar mass of CH3COOH,

MM = 2*MM(C) + 4*MM(H) + 2*MM(O)

= 2*12.01 + 4*1.008 + 2*16.0

= 60.052 g/mol

use:

mass of CH3COOH,

m = number of mol * molar mass

= 0.8846 mol * 60.05 g/mol

= 53.12 g

volume of solution = 1 L = 1000 mL

density of solution = 1.00 g/mL

Use:

mass of solution = density * volume

= 1.00 g/mL * 1000 mL

= 1000 g

Now use:

mass % of acetic acid = mass of acetic acid * 100 / mass of solution

= 53.12 * 100 / 1000

= 5.312 %

≅ 5.3%

3 0
4 years ago
In a chemical reaction, when particle size is reduced, the rate of reaction increases because of increased surface area of the
Nutka1998 [239]

Answer:

option A

for more information, refer to brainly.com/question/13441946

3 0
2 years ago
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