Answer:
0.2
Explanation:
Given parameters:
Mass of helium = 0.628g
Mass of neon = 11.491g
Mass of argon = 7.613g
Unknown:
Mole fraction of neon = ?
Solution:
The mole fraction of an element is the number of moles of that element to the total number of moles in the gas mixture.
We need to calculate the number of moles of each element first;
Number of moles =
Molar mass of Helium = 4g/mol
Molar mass of Neon = 20g/mol
Molar mass of Argon = 40g/mol
Number of moles of He = = 0.16moles
Number of moles of Ne = = 0.58moles
Number of moles of Ar = = 0.19moles
Total number of moles = 0.16moles + 0.58moles + 0.19moles = 0.93moles
Mole fraction Neon = = 0.2
Answer:
See explanation
Explanation:
You see, we must cast our minds back to Charles' law. Charles' law gives the relationship between the volume of a gas and temperature of the gas.
Now, Micheal left the balloon outside at a particular temperature and volume the previous night. Overnight, the temperature dropped significantly and so must the volume of the gas in the balloon!
Remember that Charles' law states that, the volume of a given mass of gas is directly proportional to its absolute temperature at constant pressure. Since the pressure was held constant, the drop in the volume of gas in the balloon can be accounted for by the drop in temperature overnight.
Answer:
Repeated SN2 reactions occur leading to the formation of a racemic mixture
Explanation:
S-2-iodooctane is a chiral alkyl halide with an asymmetric carbon atom. The presence of an asymmetric carbon atom implies that it can rotate plane polarized light and thus lead to optical isomerism. The two configurations of the compound are R/S according to the Cahn-Prelong-Ingold system.
However, when S-2-iodooctane is treated with sodium iodide in acetone, repeated SN2 reactions occur since the iodide ion is both a good nucleophile and a good leaving group. Hence a racemic modification is formed in the system with time hence we end up with (±)- Iodooctane.
In 1869 he published a table of the elements organized by increasing atomic mass.
Mendeleev is called the "father of the modern periodic table
stated that if the atomic weight of an element caused it to be placed in the wrong group, then the weight must be wrong. (He corrected the atomic masses of Be, In, and U)
was so confident in his table that he used it to predict the physical properties of three elements that were yet unknown.
After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev's predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.
However, in spite of Mendeleev's great achievement, problems arose when new elements were discovered and more accurate atomic weights determined.
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Answer:
c. 0.1 M Ga₂(SO₄)₃
Explanation:
The boiling point increasing of a solvent due the addition of a solute follows the formula:
ΔT = K*m*i
<em>Where K is boiling point increasing constant (Depends of the solute), m is molality = molarity when solvent is water, and i is Van't Hoff factor.</em>
<em />
That means the option with the higher m*i will be the solution with the highest boiling point:
a. NaCl has i = 2 (NaCl dissociates in Na⁺ and Cl⁻ ions).
m* i = 0.20*2 = 0.4
b. CaCl₂; i = 3. 3 ions.
m*i= 0.10M * 3 = 0.3
c. Ga₂(SO₄)₃ dissolves in 5 ions. i = 5
m*i = 0.10M*55 = 0.5
d. C₆H₁₂O₆ has i = 1:
m*i = 0.2M*1 = 0.2
The solution with highest boiling point is:
<h3>
c. 0.1 M Ga₂(SO₄)₃</h3>