Answer:
a. A buffer solution reacts with basic solutions.
c. A buffer solution reacts with acidic solutions.
e. A buffer solution resists small changes in pH
Explanation:
1. Buffer questions
a, c, and e are TRUE. A buffer resists a change in the pH when small amounts of a strong acid or base are added to it.
b is wrong. A buffer can have a pH of 7, but it can also have many other pH values.
d is wrong. Most buffers are colourless, and they resist a change in pH.
2. Titration curves
The solution is the best buffer at the mid-point of the titration curve.
In the figure below, the equivalence point is at 13 mL, so the mid-point is at 6.5 mL.
The solution is buffered at pH 3.2.
However, the solution is a buffer at any point in the range pH = 3.2 ± 1.
That would be in the range of 1 mL to 12 mL.
The buffering ability becomes worse the further you are from the mid-point of the titration.
I believe that it is all of the above.
"A Scientific Hypothesis Must Be "Falsifiable". A scientific hypothesis must be testable, but there is a much stronger requirement that a testable hypothesis must meet before it can really be considered scientific."
I hope this helped, have a nice day!
Answer:
physical change because even though gas formation was observed the water was undergoing a state change which means that it's original properties are preserved
6.52 × 10⁴ L. (3 sig. fig.)
<h3>Explanation</h3>
Helium is a noble gas. The interaction between two helium molecules is rather weak, which makes the gas rather "ideal."
Consider the ideal gas law:
,
where
is the pressure of the gas,
is the volume of the gas, 
is the number of gas particles in the gas, 
is the ideal gas constant, and
is the absolute temperature of the gas in degrees Kelvins.
The question is asking for the final volume of the gas. Rearrange the ideal gas equation for volume:
.
Both the temperature of the gas, , and the pressure on the gas changed in this process. To find the new volume of the gas, change one variable at a time.
Start with the absolute temperature of the gas:
,
.
The volume of the gas is proportional to its temperature if both and stay constant.
- won't change unless the balloon leaks, and
- consider to be constant, for calculations that include .
.
Now, keep the temperature at 
and change the pressure on the gas:
,
.
The volume of the gas is proportional to the reciprocal of its absolute temperature 
if both and stays constant. In other words,
(3 sig. fig. as in the question.).
See if you get the same result if you hold constant, change , and then move on to change .
