Which substance has the lowest vapor pressure at 75°C?(1) water (3) propanone
(2) ethanoic acid (4) ethanol
Answers
Answer : (2) Ethanoic acid has the lowest vapor pressure at .
Explanation :
Vapor pressure is the pressure which is exerted by vapor when the vapor form is in equilibrium with the solid or liquid form.
Boiling point is the temperature in which the vapor pressure of liquid is equal to the atmospheric pressure.
Vapor pressure is related with the boiling point :
vapor pressure is inversely proportional to the boiling point. As the boiling point increases, vapor pressure decreases and as the boiling point decreases, vapor pressure increases.
The standard boiling point of given liquids water, propanone, ethanoic acid and ethanol are 100, 56, 118 and respectively.
The image of graph of vapor pressure vs temperature is attached below.
Hence, Ethanoic acid is the substance which has the lowest vapor pressure.
water: has hydrogen bonding, dispersion, and dipole forces for intermolecular attraction
ethanoic acid: a carboxylic acid has one polar end with a negative charge as CH3COOH turns to CH3COO-. Hydrogen bonding is also present in pure solutions.
Propanone: is a ketone and has an electronegative oxygen attached to a carbon, but does not exhibit hydrogen bonding since the O is not attached to a hydrogen.
Ethanol: Like water exhibits hydrogen bonding, not as strong but more dispersion forces.
Next we must understand boiling points
Water: 100˚C
Ethanoic Acid: 118˚C
Propanone: 56˚C
Ethanol: 78˚C
Given this knowledge we can order the liquids in terms of decreasing volatility or decreasing vapor pressure. We now notice that Ethanoic acid, or acetic acid will have the lowest vapor pressure at 75˚C
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The amount of energy a person can consume throughout the day without gaining weight is extremely dependent onA. hunger. B. appetite. C. culture. D. activity level.
The temperature of the balloon will decrease.
The gas atoms will strike the sides of the balloon more often.
The gas inside the balloon will change into a liquid.
Answers
Answer: The gas atoms will strike the sides of the balloon more often.
Explanation:
Kinetic energy is the energy possessed by an object by virtue of its motion.
Average kinetic energy is defined as the average of the kinetic energies of all the particles present in a system. It is determined by the equation:
K= kinetic energy
R= gas constant
T= temperature
From above, it is visible that kinetic energy is directly related to the temperature of the system.
So if average kinetic energy of the system increases , the speed of the molecules will be more and hence the gas atoms will strike the sides of the balloon more often.
Hope I helped!
b. alkaline earth metals
c. transition metals
d. halogens
e. noble or inert gases
Answers
six
eight
nine
Answers
Answer:
eight
Explanation:
In the first stage of DNA replication each DNA molecule replicates into two daughter DNA. In the second stage of DNA replication each of the two daughter DNA molecule replicates into two daughter DNA, thus forming a total of four DNA molecules. In the third stage of DNA replication each of the four daughter DNA molecule replicates into two daughter DNA, thus forming a total of eight DNA molecules.
1 --> 2 ---> 4 ---> 8
Out of these 8, 2 of them contain the parent strands. So 2/8 = 1/4 = 25%
Thus the answer is the third option, eight (8).
Answers
Answers
90 /30 = 3
3 x (CH2O) = C3H6O3
Final answer:
The molecular formula of a compound with an empirical formula of CH₂O and a molar mass of 90 g/mol is C₃H₆O₃. This is found by dividing the compound's molar mass by the molar mass of the empirical formula, and using the ratio to multiply the subscripts in the empirical formula.
Explanation:
The molecular formula of a compound can be determined using the molar mass and the empirical formula given. The empirical formula for the compound is CH₂O, which has a molar mass of approximately 30 g/mol (12 g for C, 1 g for H, and 16 g for O). If the molar mass of the compound is 90 g/mol, we can find the ratio of the molar mass of the compound to the empirical formula by dividing 90 g/mol by 30 g/mol, which gives us 3.
This means the molecular formula of this compound is three times the empirical formula. So, to obtain the molecular formula, you multiply each subscript in the empirical formula by 3. If you do this for CH₂O, you get C₃H₆O₃ which is the molecular formula of the compound.
Learn more about Molecular Formula here:
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Answers
Answer:
T₂ = 379.4 K
Explanation:
Given data:
Initial volume = 1.56 L
Initial temperature = 20°C (20+273 = 293 K)
Final volume = 2.02 L
Final temperature = ?
Solution:
The given problem will be solve through the Charles Law.
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
T₂ = V₂T₁ /V₁
T₂ = 2.02 L × 293 K / 1.56 L
T₂ = 591.86 L.K / 1.56 L
T₂ = 379.4 K