This is an incomplete question, here is a complete question.
The conversion of cyclopropane to propene occurs with a first-order rate constant of 2.42 × 10⁻² hr⁻¹. How long will it take for the concentration of cyclopropane to decrease from an initial concentration 0.080 mol/L to 0.053 mol/L?
Answer : The time taken will be, 17.0 hr
Explanation :
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = initial concentration of the reactant = 0.080 M
a - x = concentration left = 0.053 M
Now put all the given values in above equation, we get


Therefore, the time taken will be, 17.0 hr
So we know the number of moles of each compound. If we need to know the concentration we must know the number of moles that the compounds react with...
Explanation:
When water vapour changes to liquid water then this process is known as condensation.
For example, when lid is placed in a hot water filled pan then after sometime vapours appear on the surface of lid. When temperature of water decreases then water vapours convert into liquid form.
Thus, we can conclude that in condensation water vapor changes to liquid water.
The correct answer is D. A solid has a high to very high melting point, great hardness , and poor electrical conduction, this is a covalent network solid. This is because of the large amount of energy required to break these bonds, the said properties are exhibited by these solids.