Given the density of ethanol = 0.79
Volume of ethanol = 75.0 mL
Calculating the mass if ethanol from density and volume:

Molar mass of ethanol = (2*atomic weight of C)+(6*atomic weight of H)+(1*atomic weight of O)
=(2*12g.mol) + (6*1g/mol) + (1*16g/mol)
=46g/mol
Moles of ethanol = 
Volume of the solution = 250.0 mL
Converting the volume from mL ot L:

Molarity of ethanol in the solution = 
Answer:
The volume of the gas at given temperature is 
Explanation:
= initial pressure of gas = 1 atm
= initial temperature of gas =
= initial volume of gas =
(
, 1 mL = 0.001 L)
..[1]
= final pressure of gas = 2.1 atm
= final temperature of gas =
= final volume of gas = ?
..[2]
By dividing [1] and [2] we get combined gas equation :,

Now put all the given values in the above equation, we get:

The volume of the gas at given temperature is 
Remember that density refers to the "mass per unit volume" of an object.
So, if an object had a mass of 100 grams and a volume of 100 milliliters, the density would be 100 grams / 100 ml.
In the question, water on the surface of the scale would add weight, so the mass of the object that you're weighing would appear to be heavier than it really is. If that happens, you'll incorrectly assume that the density is GREATER than it really is
As an example, suppose that there was 5 ml of water on the surface of the scale. Water has a density of 1 gram per milliliter (1 g/ml) so the water would add 5 grams to the object's weight. If we use the example above, the mass of the object would seem to be 105 grams, rather than 100 grams. So, you would calculate:
density = mass / volume
density = 105 grams / 100 ml
density = 1.05 g/ml
The effect on density would be that it would erroneously appear to be greater
Hope this helps!
Good luck
The physical properties of alkenes and alkynes are generally similar to those of alkanes or cycloalkanes with equal numbers of carbon atoms. Alkynes have higher boiling points than alkanes or alkenes, because the electric field of an alkyne, with its increased number of weakly held π electrons, is more easily distorted, producing stronger attractive forces between molecules.
Answer:
Option B
Explanation:
Salt is a non-volatile solute and hence adding salt will increase the boiling point of water and hence reduce the vapor pressure. While on the other hand, adding more water will require more time to boil and hence produce vapor and thus the vapor pressure. Shaking will also not help in increasing the vapor pressure. Thus, only increasing the temperature of the water will create more vapors at a faster rate and hence increase the vapor pressure.
Thus, option B is the correct answer