I believe the answer is 11, its been awhile since i was in science
do you mean fractional distillation of crude oil ?
if you do then this is what happens:
basically, crude oil is made up of a lot of hydrocarbons so it's put into a fracitonating column to separate these compounds into fractions. the top of the fractionating column is colder whereas the bottom of the column is hotter.
gases, petrol, diesel and kerosene come out near the top of the top of the column because they are shorter chains. substances near the top of the column also have a lower boiling point (since it's cooler and there's less intermolecular forces).
the substances at the top of the column are typically useful fuels because they have a higher ease of ignition (higher up=easier to ignite, lower down = harder to ignite). Also, substances at the top have a low viscosity so they can flow easily.
substances that come out near the bottom of the fracitonating column include fuel oil and bitumen.
these are longer chains of hydrocarbons and bitumen is used for road surfacing.
these substances have a high viscosity (harder to flow) and have a high boiling point since they have more intermolecular forces which require a lot of energy to break. Also the bottom of the fractionating column is warmer and this is where these fractions are released.
Answer:
The correct choices are:
- <em>using accurate measurements</em>
- <em>using pure chemicals</em>
- <em>performing the reaction under the most ideal conditions</em>
Explanation:
The theoretical yield is the maximum amount of product that could be obtained by the chemical reaction, from a given amount of reactants. You calculate the theoretical yield using the stoichiometry coefficients of the balanced chemical equation.
The <em>percent yield </em>is the ratio of the actual yield (the actual amount obtained) of a product to the theoretical yield for the same product, expressed as a percentage (i.e. multiplied by 100).
- percent yield = actual yield × 100 / theoretical yield
As the actual yield decrease (the numerator of the ratio), the percent yield decrease.
To increase the percent yield it is important:
- using accurate measurements
- performing the reaction under the most ideal conditions
<em><u>Using accurate measurements:</u></em> if you do not add the correct amounts of each reactant, then the product obtained will not be what you can predict from the theoretical calculations and you will be wasteing one or other reactant, without reaching the maximum yield possible.
<em><u>Using pure chemicals:</u></em> if the chemicals are not pure, the amount of actual reactants will be lower than they should be, leading to a lower actual yield.
<em><u>Performing the reaction under the most ideal conditions:</u></em> the actual rate of reactions depend on the conditions: temperature and pressure are the most commons. Since, temperature and pressure may change that rate of reactions, you should find and use the most ideal conditions to get the greatest actual yield.
<em>Adding water</em>, can just dilute the reactants and would decrease the rate of reaction, which would not be helpful to increase the yield.
Answer:
it's a covalent compound
Explanation:
Two non metals are bonded to together
H H
I I
H - C - C - H
l l
H H
A Carbon can only form 4 bonds and a Hydrogen can only form 1 bond.
