The structure of 1-methoxypropane is CH₃-CH₂-CH₂-OCH₃
I will label the carbons A-D from left to right.
A B C D
CH₃-CH₂-CH₂-OCH₃
In a proton NMR spectrum, we are looking at the chemical shifts of each unique hydrogen atom, and the splitting patterns tell us how many hydrogens are attached to the adjacent carbon. Therefore, the signal from the protons on carbon A will be split by the protons on carbon B, and the signal for protons on carbon A will have a splitting pattern equal to n+1, where n = number of hydrogens on the adjacent carbon.
Therefore, for the protons on carbon A, there are two neighbouring protons and these will give a splitting patter of 3 peaks, also known as a triplet.
Protons on carbon A: 2 adjacent protons result in a triplet signal.
Protons on carbon B: 5 adjacent protons result in a sextet signal.
Protons on carbon C: 2 adjacent protons result in a triplet signal.
Protons on carbon D: 0 adjacent protons result in a singlet signal.
Explanation:
For reacting with 8.75 grams of oxygen, 1.08 grams of hydrogen is required.
The given balanced equation has been:
\rm O_2\;+\;2\;H_2\;\rightarrow\;H_2OO2+2H2→H2O
From the equation, 1 mole of oxygen reacts with 2 mole of hydrogen to give 1 mole of water.
The mass of oxygen has been: 8.75 g,
Moles = \rm \dfrac{weight}{molecular\;weight}molecularweightweight
Moles of oxygen = \rm \dfrac{8.75}{32}328.75
Moles of oxygen = 0.27 mol
Since,
1 mole Oxygen = 2 mole hydrogen
0.21 mol oxygen = 0.54 mol hydrogen
Mass of hydrogen = moles \times× molecular weight
Mass of hydrogen = 0.54 \times× 2
Mass of hydrogen = 1.08 grams.
Thus, for reacting with 8.75 grams of oxygen, 1.08 grams of hydrogen is required.
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.
Initial volume (without silver): 25.0 mL
final volume (with silver): 54.8 mL
1 mL = 1 cm3 (you can just change the units and the numbers will be the same)
volume of silver piece:
54.8 cm3 - 25.0 cm3 = 29.8 cm3
