Answer:
Positive: a and b
Negative: c
Explanation:
The entropy (S) is the measure of the randomness of the system, and it intends to increase. The randomness can be determined by the energy of the molecules, their velocity and how distance they are between the other molecules.
When the entropy increases, ΔS is positive, when the entropy decreases, ΔS is negative. So, when gasoline mix with air in a car engine, the process intends to continue, the randomness increases and ΔS is positive. When hot air expands, the distance between the molecules increases, so ΔS is positive.
But, when humidity condenses, the molecules stay closer, so there's a decrease in the randomness, then ΔS is negative.
SI units or International System of Units is defined as basic set of measurement of seven units. The physical quantities and base units are as follows:
Length is measured in meter (m), mass in kilogram (kg), time in second (s), electric current in ampere (A), temperature in Kelvin (K), luminous intensity in candela (cd) and amount of substance in mole (mol).
Therefore, SI units of physical quantities is known as base units and other units are known as derived units because they can derived from the SI units.
Thus, the correct match will be:




From the rest of the units, degree Fahrenheit is derived unit for temperature, gram is derived unit for mass, nanosecond is derived unit for time and candela is SI unit for luminous intensity.
Molar mass of N2H4 = 32 grams/mole
<span>3.95 grams of N2H4 = 3.95/32
= 0.123 moles </span>
<span>This will produce 0.123 moles of N2 </span>
<span>Now,
From the gas law equation. </span>
<span>P.V = n x R x T </span>
<span>P = 1 atm (given)
V = </span><span>0.123</span><span> x 0.082057 x 295 </span>
<span>V = 2.97 Liters </span>
<span>Theoretical yield = 2.97 Liters.
Actual yield = 0.750 Liters </span>
percentage yield = (0.75/2.97) x 100 %
= 25.25 %