After Dalton's proposed atomic theory, several atomic models were developed. Which model was the first propose the existence of

Chemistry

1 answer:

Lostsunrise [7]3 years ago

7 0

Answer: Rutherford's model was the first propose of the existence of small, dense nucleus's.

Explanation: The atom, as described by Ernest Rutherford, has a tiny, massive core called the nucleus. The nucleus has a positive charge. Electrons are particles with a negative charge. Electrons orbit the nucleus. The empty space between the nucleus and the electrons takes up most of the volume of the atom.

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Draw the product that valine forms when it reacts with excess CH3CH2OH and HCl followed by a wash with aqueous base.

-BARSIC- [3]

Answer:

Product: ethyl L-valinate

Explanation:

If we want to understand what it is the molecule produced we have to analyze the reagents. We have valine an amino acid, in this kind of compounds we have an amine group ( $NH_2$ ) and a carboxylic acid group ( $COOH$ ). Additionally, we have an alcohol ( $CH_3CH_2OH$ ) in the presence of HCl (a strong acid) in the first step, and a base ( $OH^-$ ).

When we have an acid and an alcohol in a vessel we will have an esterification reaction. In other words, an ester is produced. As the first step, the oxygen in the C=O (in the carboxylic acid group) would be protonated. In the second step, the ethanol attacks the carbon in the C=O of the carboxylic acid group producing a new bond between the oxygen in the ethanol and the carbon in the carboxylic acid. In step 3, a proton is transferred to produce a better leaving group ( $H_2O$ ). In step 4, a water molecule leaves the main structure to produce again the double bond C=O. Finally, a base ( $OH^-$ ) removes the hydrogen from the C=O bond to produce ethyl L-valinate

See figure 1

I hope it helps!

7 0

3 years ago

How do you separate alcoh0l from water?

Xelga [282]

Answer:

Fractional distillation

Explanation:

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3 years ago

Investigate Weathering and Erosion 1. Describe at least one part of the experimental procedure that you thought was essential to

zvonat [6]

Answer:

Controlling the environment is the most key procedures for getting good results.

Explanation:

The control environment for an experiment is the essential part for getting good results. In control environment, there is no or less chances of disruption

from the external environment which can cause the results of the data more acceptable. So the scientists prefers laboratory for performing experiment as compared to outer environment. So in my opinion for getting better results, the control environment is the most necessary experimental procedure.

4 0

3 years ago

Read 2 more answers

Please help with the attached picture question 21, 22, 23

klasskru [66]

Explanation:

21. The given molecule for cracking is tetradecane.

On cracking it forms one mole of decane (C10H22) and two moles of ethene gas.

The chemical equation is shown below:

$C_1_4H_3_0->C_1_0H_2_2+2C_2H_4$