The answer to your question
b. sublimation
2. Calculate the moles of O in the sample.
Answer:
The answers are
C = 0.0895 moles
1. 0.02975 moles of N
2. 0.0299 moles O
Explanation:
Mass of sample = 2.18 g
Combustion yields 3.94 g of CO₂ and 1.89 g of H₂O
1.23 g of sample contains 0.235 g of N
3.94 g of CO₂ which contains one mole of C and two moles of O
Molar mass of CO₂ = 44 mass fraction of C = 12/44 = 0.273, Therefore mass of carbon in 2.18 g = 0.273×3.94 = 1.075 g
number of moles of C in sample = mass/(molar mass) = 1.075 g/(12.01 g/mol) = 0.0895 moles of C
(1) Mass of nitrogen, in 1.23 g of sample = 0.235
therefore mass in 2.18 g =0.235×2.18/1.23 = 0.4165 g
= 0.02975 moles of N
(2) To find the number of moles of oxygen in the sample we note that total mass of sample = 2.18 g containing only nitrogen, hydrogen, oxygen and carbon
Mass of hydrogen can be fround from 2/18×1.89 = 0.21 g
Mass of oxygen therefore = 2.18 -(0.21+0.4165+1.075) = 0.4785
number of moles = 0.475/16 = 0.0299 moles
To know the end point we use phenolphthalein as indicator. Therefore, endpoint is point in which indicator change the color, and equivalence point is point in which there is equal amount of two chemicals.
Titration is a technique by which we know the concentration of unknown solution using titration of this solution with solution whose concentration is known. To know the end point we use phenolphthalein as indicator. End point is a point where completion of reaction happen.
Endpoint is point in which indicator change the color, and equivalence point is point in which there is equal amount of two chemicals. Endpoint is after Equivalence point.
Therefore, endpoint is point in which indicator change the color, and equivalence point is point in which there is equal amount of two chemicals.
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Answer:
Endpoint is point in which indicator change the color, and equivalence point is point in which there is equal amount of two chemicals. Endpoint is after Equivalence point.
Explanation:
Answer:
The Barium flame is green because it is a difficult flame to excite, therefore for it to trigger a flame it is necessary that it be too excited for it to occur.
The reddish color of calcium is due to its high volatility and it is sometimes very difficult to differentiate it from strontium.the compression of these elements is due to being able to make them work during combustion
Explanation:
The flame test is a widely used qualitative analysis method to identify the presence of a certain chemical element in a sample. To carry it out you must have a gas burner. Usually a Bunsen burner, since the temperature of the flame is high enough to carry out the experience (a wick burner with an alcohol tank is not useful). The flame temperature of the Bunsen burner must first be adjusted until it is no longer yellowish and has a bluish hue to the body of the flame and a colorless envelope. Then the tip of a clean platinum or nichrome rod (an alloy of nickel and chromium), or failing that of glass, is impregnated with a small amount of the substance to be analyzed and, subsequently, the rod is introduced into the flame, trying to locate the tip in the least colored part of the flame.
The electrons in these will jump to higher levels from the lower levels and immediately (the time that an electron can be in higher levels is of the order of nanoseconds), they will emit energy in all directions in the form of electromagnetic radiation (light) of frequencies characteristics. This is what is called an atomic emission spectrum.
At a macroscopic level, it is observed that the sample, when heated in the flame, will provide a characteristic color to it. For example, if the tip of a rod is impregnated with a drop of Ca2 + solution (the previous notation indicates that it is the calcium ion, that is, the calcium atom that has lost two electrons), the color observed is brick red .
Answer:
The different colours produced come from the different wavelength of the spectrum of light as the excited electrons in the metals return to their original state on cooling down.
Explanation:
The flame test is an analytical procedure used to identify different metals by passing them through a flame.
The flame, which is a source of heat energy heats up the metals and excites their outermost electrons which transit to the next energy level. On cooling down, as the excited electrons return to their original state, they emit different colours corresponding to the spectrum of light. Electrons of larger atoms like Barium emit light of higher frequency and lower wavelength and hence exhibits colours closer to the ultraviolet part of the electromagnetic spectrum while smaller atoms like Calcium emit light of lower frequency and higher wavelength and emit light closer to the infrared part of the spectrum
Baruim (atomic number 56) and Calcium (atomic number 20) are both metals in group two of the periodic table.
They both have two electrons in their outermost shell and are represented by Ba²⁺ and Ca²⁺.
When both metals are passed to through the flame test, the two outermost electrons in both metals are excited.
However because the outermost electrons in Barium are farther to the nucleus than those in Calcium, it takes a lesser amount of heat energy to excite them than that of Calcium which is closer to the nucleus.
The spectrum of light which is usually represented by 'ROYGBIV' has the following colours : Red, Orange,Yellow, Green, Indigo and Violet with Red having their highest wavelength (or shortest frequency) and Violet the shortest wavelength (or highest frequency).
Barium's green colour is because it outermost electrons emit light in the range of the Green spectrum of light and calcium's red colour is because its outermost electrons emit light in the range of the Red spectrum of light
B. ^23 V
C. ^23 Mn
D. ^51 Sb
E. ^51 V
Answer:
E. ^51 V
Atomic number (number of protons in the nucleus): 23
Atomic symbol (on the periodic table of the elements): V
Atomic weight (average mass of the atom): 50.9415
Density: grams per cubic centimeter
Phase at room temperature: Solid
Melting point: 3,470 degrees Fahrenheit (1,910 degrees Celsius)
Boiling point: 6,165 F (3,407 C)
Number of isotopes (atoms of the same element with a different number of neutrons): 2; one stable V-51; one radioactive V-50
Most common isotopes: V-51 (99.75 percent natural abundance)
Note: Each number represents the sentence that comes before it in the scenario.
Answer: Sentence (4) is the correct answer.
Explanation:
Physical properties are defined as the properties that does not bring any change in chemical composition of a substance.
For example, density, volume, mass, shape, size etc are all physical properties.
So, when Sherry opens the cap of her lip balm tube then some of it drips because semi-solid state of lip balm has changed into liquid state due to absorption of heat from the car.
This means that there occurs change in only physical property of the lip balm.
Therefore, we can conclude that sentence from the scenario best shows Sherry's lack of understanding about the physical properties of her lip balm is that when she takes the cap off to apply it, some of it drips out of the tube and makes a mess all over her hands.