Answer: The correct option is option d
Explanation - The mean deal with science is that it allows people to carry on research in an organized manner to find or make new discoveries and inventions.
The basic purpose of science is to try new things or ways to get an outcome by constant perseverance on research and negating the ways that don't work thus giving and improving knowledge of what is correct and what is not to make a new Discovery or invention.
Answer:
The answer to your question is 0.5 liters
Explanation:
Data
[CaCl₂] = 4.0 M
number of moles = 2
volume = ?
Process
To solve this problem use the formula of Molarity and solve it for volume, substitute the values and simplify.
-Formula
Molarity = moles / volume
-Solve for volume
Volume = moles / molarity
-Substitution
Volume = 2/4
-Simplification
Volume = 0.5 liters.
Answer:
Explanation:
The usefulness of a buffer is its ability to resist changes in pH when small quantities of base or acid are added to it. This ability is the consequence of having both the conjugate base and the weak acid present in solution which will consume the added base or acid.
This capacity is lost if the ratio of the concentration of conjugate base to the concentration of weak acid differ by an order of magnitude. Since buffers having ratios differing by more will have their pH driven by either the weak acid or its conjugate base .
From the Henderson-Hasselbach equation we have that
pH = pKa + log [A⁻]/[HA]
thus
0.1 ≤ [A⁻]/[HA] ≤ 10
Therefore the log of this range is -1 to 1, and the pH will have a useful range of within +/- 1 the pKa of the buffer.
Now we are equipped to answer our question:
pH range = 3.9 +/- 1 = 2.9 through 4.9
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