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:
151.94 u
Explanation:
The atomic mass of Eu is the <em>weighted average</em> of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its <em>percent abundance</em>).
The atomic masses of Eu-151 and Eu-153 are 150.92 u and 152.92 u, respectively.
Set up a table for easy calculation.
0.4803 × 150.92 u = 72.472 u
0.5197 × 152.92 u = <u> 79.473 u
</u>
TOTAL = 151.94 u
So, we have:
- molecular weight
- shape
- temperature
- kinetic energy
- mass
- density
Let's rule out the different options.
- molecular weight: Say you have a molecule of H2O. H2O can be a solid, liquid, or gas, but its molecular weight never changes throughout (It's still the same molecule, no matter what phase it is in). We can rule this out.
- shape: Let's pretend we have three identical closed containers, and we fill each one halfway with water, blocks of ice cubes, and water vapor. In the container with water, you will see that the water takes the shape of the container, but doesn't fill the entire container up. The ice cubes will stay ice cubes, assuming they don't melt, so they don't take the shape of the container. The vapor will fill up the entire container. Since all three are different, I would say yes, this could be a distinguishable feature.
- temperature: In general, I would say no, because every element/molecule has different boiling points and different vaporization points. So if you have a liquid at 5°C, you could also have a different element in solid form at 5°C. But if you're comparing a single type of molecule, it would have a boiling point and a vaporization point, so you <em>would</em> be able to tell between them.
- kinetic energy: Kinetic energy refers to how much movement there is in respect to each molecule. In solids, the molecules are packed tightly together and can't move very much, so they have lower kinetic energy. In liquids, they are less packed, but still restricted. And in gases, they can fly freely, so they will have much more kinetic energy than liquids or solids. This one's a yes.
- mass: No matter what form, there are still the same amount of molecules, and each molecule has the same mass as before. It won't change.
- density: Since the molecules are more spread out in gases, it will be less dense. Liquids will be more dense, and solids will have the greatest density. So, yes.
Conclusion: shape, kinetic energy, density, (and temperature if it's talking about a single type of molecule)
Answer:
The empirical formula is the simplest form;
Given:
Oxygen O at 94.1% and
H at 5.9%
Assume 100grams.
94% = 0.941 x 100gm. = 94.1 gm x 1mole/16gm. = 5.88 moles of O
5.9% = 0.059 x 100gm. = 5.9gm. X 1moleH/1.002gm. = 5.88 moles of H
There is one mole of O for each mole of H so the empirical formula is 
and written as OH.
