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
Answer: (C)
The frequency increases as the wavelength decreases
Explanation:
The relation between the frequency and wavelength of a wave is
Frequency = 1 / Wavelength
The Frequency of electromagnetic wave is inversely proportional to the wavelength. So, as the frequency increases, the wavelength of the wave decreases and vise-versa.
The frequency of a wave is number of complete cycles passing a particular point per second. Its S.I unit is Hertz whereas the wavelength of a wave is the distance between two consecutive crest and trough in meters.
So, on increasing the frequency of a wave, there will be more number of the cycles of wave per second which will decrease the distance between the consecutive crest and trough i.e wavelength.
A. Its temperature will rise continuously until it completely melts
I don't believe that any of the other answers are correct because the ice cannot stay at a certain temperature if it is melting.
Answer:
It's better to explain it.
Explanation:
Neutrons do not affect the electron configuration, but the sum of atomic number and the number of neutrons, or neutron number, is the mass of the nucleus. You know that neutrons are found in the nucleus of an atom. Under normal conditions, protons and neutrons stick together in the nucleus. During radioactive decay, they may be knocked out of there. Neutron numbers are able to change the mass of atoms, because they weigh about as much as a proton and electron together. if your asking What is the role of a neutron in an atom? then, Neutrons are very important in providing stability for an atom. Some atoms don't "need" neutrons - The hydrogen atom does not have any neutrons. However, as the atomic number ( # of protons ) increases, the number of neutrons increases as well.
Protons don't like each other. Naturally, 'positive charges repel', so it wouldn't be possible to have more than one proton in the nucleus. Here's where the neutron comes in.
Hope this helps. :)
Answer:
- <u><em>Sodium chloride</em></u>
Explanation:
The attached graph with a green and a red arrow facilitates the understanding of this explanation.
To read the <em>solubility </em>on the <em>graph</em>, you can start with the temperature, on the x-axis.
The red vertical arrow shows how, departing from the <em>40ºC temperature</em> on the x-axis, you intersect the<em> solutibility curve </em>of sodium chloride at a height (y-axis) corresponding to <em>60 g/100cm³ of water</em> (follow the green horizontal arrow).
Hence, <em>sodium chloride is the salt that can dissolve at a concentration of about 60g/100cm³ of water at 40ºC.</em>
