Hello. This question is incomplete. The full question is:
A chemist must prepare 500.0mL of hydrobromic acid solution with a pH of 0.50 at 25°C. He will do this in three steps: Fill a 500.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (5.0M) stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to significant digits.
Answer:
31.62 mL
Explanation:
To achieve this result, you must start by calculating the H + concentration. You will do this using the following formula:
pH = -log [H +]
0.50 = -log [H +]
[H +] = 10 ^ -0.50
[H +] = 0.31623 mol / L
After that you must consider that hydrobromic acid will have a weak capacity to disassociate, since it has a strong nature. In this case, we can consider that [HBr] = [H +] = 0.31623 mol / L.
After reaching this reason, it is necessary that you dilute the stock solution, using the formula:
C1V1 = C2V2
5.0 * V1 = 0.31623 * 500.0
V1 = 31.62 mL
And so you finish the answer.
Answer:
Heated copper metal reacts with oxygen to form the black copper oxide. The copper oxide can then react with the hydrogen gas to form the copper metal and water.
Answer:
Explanation:
Because the image of the graduated cylinder in your question was not attached when sending it in, I have attached one which I would use to explain the answer given.
In taking readings of liquids from a measuring cylinder, you must be at eye level from the apparatus, after which you are to take reading from below the meniscus (the lower curve) of the water.
From the image I attached, that would be 24ml.
Please apply the following to your image. I hope this was helpful.
Answer:
The boiling and freezing temperatures of krypton at absolute scale are 119.95 K and 116.05 K, respectively.
Explanation:
The absolute temperature on SI units corresponds to Kelvin scale, whose conversion formula in terms of the Celsius scale is:

Where:
- Absolute temperature, measured in Kelvins.
- Relative temperature, measured in Celsius.
Finally, freezing and boiling temperatures are converted into absolute scale:
Boiling temperature


Freezing temperature


The boiling and freezing temperatures of krypton at absolute scale are 119.95 K and 116.05 K, respectively.