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3 years ago

Describe how the proton, electron and neutron were experimentally discovered.

1 answer:

alexandr1967 [171]3 years ago

5 0

The discovery of protons can be attributed to Rutherford. ... Given the discoveries of electrons in 1897 by Thomson, Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms. Thomson proposed the name 'positive rays'.

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Why should you prefer dry ashing to wet ashing of food sample such as cabbage

julia-pushkina [17]

Answer:

Wet ashing is primarily used in the preparation of samples for subsequent analysis of specific minerals . It breaks down and removes the organic matrix surrounding the minerals so that they are left in an aqueous solution

Explanation:

8 0

2 years ago

What do acids do in solution?

KiRa [710]

B
The answer should be B.....

3 0

2 years ago

The natural abundances of elements in the human body, expressed as percent by mass, are: oxygen (O),65 percent; carbon (C), 18 p

almond37 [142]

Answer:

The mass in grams of each element in the body of 62 Kg are

Oxygen 40300 g

Carbon 11160 g

Hydrogen 6200 g

Nitrogen 1860 g

Calcium 992 g

Phosphorus 744 g

Other elements 744 g

It is possible to check it adding all the components, the total is 62000 g.

Explanation:

Firstly, we have a total mass of 62 Kg and the composition as a percentage of each component.

Percentage ( %)

Oxygen 65.0

Carbon 18.0

Hydrogen 10.0

Nitrogen 3.0

Calcium 1.6

Phosphorus 1.2

Other elements 1.2

Taking the definition of a percentage as part of hundred total, each percentage can be expressed as a decimal number. We should divide the percentage with 100 of total. For example: Oxygen 65%, it means 65/100 = 0.65. So, Oxygen is 0.65 in decimal numbers. We do the same for each component.

Percentage ( %) Decimal number

Oxygen 65.0 65/100 = 0.65

Carbon 18.0 18/100 = 0.18

Hydrogen 10.0 10/100 = 0.10

Nitrogen 3.0 3/100 = 0.03

Calcium 1.6 1.6/100 = 0.016

Phosphorus 1.2 1.2/100 = 0.012

Other elements 1.2 1.2/100 = 0.012

Finally. We can multiply decimal number of each component taking the total. 1 Kg is equivalent to 1000 g.

So, 62 Kg = 62 * 1000 g = 62000 g

After that we get the mass in grams of each element, by multiplying 62000 g and the decimal number of each component as follows:

Percentage ( %) Decimal number Mass in grams (g)

Oxygen 65.0 65/100 = 0.65 0.65*62000=40300

Carbon 18.0 18/100 = 0.18 0.18*62000= 11160

Hydrogen 10.0 10/100 = 0.10 0.10*62000= 6200

Nitrogen 3.0 3/100 = 0.03 0.03*62000= 1860

Calcium 1.6 1.6/100 = 0.016 0.016*62000= 992

Phosphorus 1.2 1.2/100 = 0.012 0.012*62000=744

Other elements 1.2 1.2/100 = 0.012 0.012*62000=744

5 0

3 years ago

a book with a mass of 1 kg is dropped from a height of 3 m. what is the potential energy of the book when it reaches the floor?

mafiozo [28]

Well, first of all, the formula for finding potential energy is;
PE=mgh
Where; m is the mass
g is the gravitational force or acceleration due to gravity
h is the height.
Anyway, according to the question, the mass is 1kg, the acceleration due to gravity has a constant value of 10ms² . And the height is 3m. Now you just have to use all these in the formula. So;
mgh= 1 x 10 x 3. That will be 30. And the unit of potential energy is Joule. So the answer is 30 joules. Hope i helped. Have a nice day.

5 0

3 years ago

The aldol reaction is catalyzed by acid as well as base. What is the reactive nucleophile in the acid-catalyzed aldol reaction

svp [43]

Answer:

The reactive nucleophile is Ketone.

Explanation:

In organic chemistry, The process of acid - catalyzed aldol condensation starts from when ketone (or any aldehyde) is converted to an -enol, after which it attacks another ketone/aldehyde that has already been activated by parbonyl oxygen protonation.

The process of this is that first of all the ketone undergoes tautomerization to form -enol. Thereafter, the other carbonyl will undergo protonation which makes the carbon activated towards attack. Now, the nucleophilic enol will be added to the carbonyl in a [1,2]-addition reaction and we will now use deprotonation to obtain the neutral Aldol product.

Now, since only the ketone can produce an -enol, thus it is the nucleophile as aldehydes are better electrophiles

4 0

2 years ago