Answer:
Buffers are resistant to high pH changes.
Explanation:
This perfectly explains the reason why we use buffers. Buffers are substances which consist of a weak acid and its conjugate base. Buffers are resistant to significant pH changes upon addition of strong acids or bases. To illustrate this, let's say we have a buffer consisting of 0.1 mol of HF, a weak acid, and 0.1 mol of NaF (fluoride is a conjugate base of HF).
- Let's say we add some strong acid, in a general form, this acid would be represented as . In this case, conjugate base will react and neutralize it to produce some amount of HF: .
- Similarly, if we add some strong base , the acidic component will react with it to produce some amount of conjugate base: . The ratio of HF to NaF in this case is held around the same value for addition of small amounts of strong acids/bases, so pH is kept almost constant, while in neutral water, pH would drastically increase or decrease.
id say theres a good plenty!
Answer: The student observed only one liquid phase because The student removed the aqueous layer instead of the organic layer and then added organic solvent to more organic layer. Diethyl ether is less dense than water.
Explanation:
In organic chemistry, which is the chemistry of carbon atoms, liquid-liquid extraction techniques are used to separate solutes from its crude reaction mixtures. An example of liquid- liquid extraction technique used is the Separatory funnel.
The Separatory funnel extraction technique allows the separation of solutes based on their solubilities in two immiscible liquids. This appears as two phases or layers with the organic solvent on top while the aqueous solution is below the funnel. This is because the organic solvents are less dense than the aqueous solution.
From the question, the student had a dissolved organic compound in an aqueous solution and was given an organic solvent, diethyl ether for its extraction. When the first 10ml of ether was added, the dissolved organic compound mixed with it and remained in the top layer of the mixture. The student removes the lower layer after the first extraction and adds the second 10mL portion of ether to the upper layer remaining in the separatory funnel. After shaking the funnel, the student observes only one liquid phase with no interface because more organic solvent was added to the organic layer that remained after the aqueous layer was removed.
<u>Answer:</u> The for the reaction is 15 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:
The intermediate balanced chemical reaction are:
(1) ( × 2)
(2)
(3)
The expression for enthalpy of the reaction follows:
Putting values in above equation, we get:
Hence, the for the reaction is 15 kJ.
When we take a look at the periodic table of elements we can see that Fluoride has the atomic number of 9. What this means is that this atom has 9 protons and 9 electrons. Since the fluorine ion has a negative charge of one, that means that the fluorine ion has one more electron than the fluorine atom.
So, the F- ion has 9 protons and 10 electrons.