Answer:
It is necessary because Trans-cinnamic is a limiting reagent in the mixture reaction while Bromine is the excess reagent
Explanation:
It is necessary to maintain excess bromine in the reaction mixture because Bromine is the excess reagent in the reaction mixture and if it's quantity is less it would consume the limiting reagent ( Trans-cinnamic ) completely . hence Bromine should maintain excess quantity in the reaction mixture
Answer:- 71.7 calories
Solution:- it is a unit conversion problem where we need to convert joules into calories.
The unit conversion for these energy units is:
1 calorie = 4.184 joule
The given energy is 300 joules and has to be converted to calories. We will show the set up using dimensional analysis.
= 71.7 calories
So, the energy in calories is 71.7.
Answer:
Hydrogen
Explanation:
Balloons are filled with light gases in order to make them float. Helium and Hydrogen are both light gases.
Helium is quite a lot lighter than air: it's about an eighth of the density of air. Hydrogen is about a sixteenth the density of air, so it'll float in air and will in fact float upwards.
Hydrogen however is twice as heavy as helium, but that doesn't mean the amount of lift off of the balloon is twice as much. The amount of lift is determined by the difference in density with respect to air.
Hydrogen is calculated to be less dense than helium, that explains why hydrogen filled balloons would go up higher.
Helium filled balloons are used because of the safety implications. The problem is that hydrogen is explosive may have some health and safety implications! Helium is much more safe to use.
The correct is this because they said
Answer:
Mole fraction of Nacl is 0.173
Explanation:
we know that
where,
P
sol - the vapor pressure of the solution
χ solvent - the mole fraction of the solvent
P
∘
solvent - the vapor pressure of the pure solvent
This means that in order to be able to calculate the mole fraction of sodium chloride, you need to know what the vapor pressure of pure water is at
25
°
C You can use an online calculator to find that the vapor pressure of pure water at 25 C is equal to about 23.8 torr
.
=0.827
Also we know that
This means that the mole fraction of sodium chloride is
χ_{Nacl}= 1-Χ_{water}
= 1-0.827 =0.173
