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3 years ago

Suppose that Biuret reagent turns purple when it is added to an unknown substance. What can you conclude about the substance?

Chemistry

1 answer:

Oksi-84 [34.3K]3 years ago

6 0

Answer:

the unknown substance is a protein

Explanation:

The biuret test is one of the tests for proteins. It can be used to detect peptide linkages. The biuret test is carried out in an alkaline solution. A coordination complex is formed leading to the appearance of a violet color.

Summarily, the biuret method is a colorimetric technique used to test for proteins and peptides. It involves the formation of a purple (violet) complex of Copper salts in alkaline solution.

Hence when the biuret reagent is added to an unknown substance and it turns purple, the unknown substance is a protein

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A student is given a sample of a blue copper sulfate hydrate. He weighs the sample in a dry covered porcelain crucible and got a

Nata [24]

Answer:

There are present 5,5668 moles of water per mole of CuSO₄.

Explanation:

The mass of CuSO₄ anhydrous is:

23,403g - 22,652g = 0,751g.

mass of crucible+lid+CuSO₄ - mass of crucible+lid

As molar mass of CuSO₄ is 159,609g/mol. The moles are:

0,751g × $\frac{1mol}{159,609g}$ = 4,7052x10⁻³ moles CuSO₄

Now, the mass of water present in the initial sample is:

23,875g - 0,751g - 22,652g = 0,472g.

mass of crucible+lid+CuSO₄hydrate - CuSO₄ - mass of crucible+lid

As molar mass of H₂O is 18,02g/mol. The moles are:

0,472g × $\frac{1mol}{18,02g}$ = 2,6193x10⁻² moles H₂O

The ratio of moles H₂O:CuSO₄ is:

2,6193x10⁻² moles H₂O / 4,7052x10⁻³ moles CuSO₄ = 5,5668

That means that you have 5,5668 moles of water per mole of CuSO₄.

I hope it helps!

5 0

3 years ago

In which environment would a forensic scientist not be found?

mrs_skeptik [129]

The correct answer is D. In a police interrogation room, questioning the suspect.

Explanation:

Forensic scientists are experts who use science as part of criminal investigations. Indeed, the main role of these experts is to deal with the evidence related to the crime to help authorities understand how the crime occurred and who was involved in this.

Because of this, the forensic scientist's role includes collecting evidence, analyzing samples, participating as witnesses in trials, and in some cases teach other experts about techniques. However, forensic scientists cannot interrogate suspects as they only deal with evidence and this process is in charge of the police.

6 0

3 years ago

Name one manufactured device or natural phenomenon that emits electromagnetic radiation in each of the following wavelengths: ra

Bas_tet [7]

Radio - Radio station transmits radio wavelength which is received by the
Radio.

Microwaves - Microwave Oven to heat up foods. 

IR (infrared) - TV remote Control, to transmit IR light to a sensor in the TV so it can do some functions like increasing the volume, changing the channel etc. 

Visible light - Sunlight or Light Bulbs 

Ultraviolet - UV Lamps for sun tan, for detecting forged money 

X-rays - Chest X-ray machines, Backscatter Xray (body scanner in airport security)

Gamma rays - Gamma rays Medical Equipment which are used to kill cancer cells, to sterilize medical equipment

7 0

3 years ago

Can someone check if i did this right. thank you !!

Tasya [4]

Answer:

noo

Explanation:

its basic

....................

6 0

3 years ago

Read 2 more answers

A sample of hydrogen gas occupies

Brums [2.3K]

Answer:

look it up and it gives you the answer in one of the slides ;]

Explanation:

3 0

2 years ago