One student calibrated a 50-mL burette by using the mass of water delivered. The student used an analytical balance which was previously calibrated by STEEL (density = 7.8 g/mL). During calibration, the temperature of water was found to be 19.0oC. The density of water at this temperature is 0.9984 g/mL. The results of the calibration by the student is shown in the table below:
A B C D E
Apparent burette reading, mL 10.05 20.04 30.08 40.07 49.98
Weight H2O delivered, g 10.03 20.09 30.05 40.02 49.83
Questions:
What is the true mass of water delivered in A?
A) 10.03 B) 10.04 C) 10.05 D) 10.06 E) 10.07
What is the true mass of water delivered in B?
A) 20.12 B) 20.13 C) 20.14 D) 20.15 E) 20.16
What is the true mass of water delivered in C?
A) 30.13 B) 30.11 C) 30.10 D) 30.09 E) 30.08
What is the true mass of water delivered in D?
A) 40.09 B) 40.08 C) 40.07 D) 40.06 E) 40.05
What is the true volume of water delivered in A?
A) 10.00 B) 10.02 C) 10.04 D) 10.06 E) 10.08
What is the true volume of water delivered in B?
A) 20.12 B) 20.14 C) 20.16 D) 20.18 E) 20.20
What is the true volume of water delivered in D?
A) 40.11 B) 40.12 C) 40.13 D) 40.14 E) 40.15
What is the true volume of water delivered in E?
A) 50.00 B) 49.98 C) 49.96 D) 49.94 E) 49.92
What is the correction volume of water delivered in C?
A) 0.04 B) 0.08 C) 0.00 D) -0.04 E) -0.08
What is the true volume of water delivered in D?
A) 0.11 B) 0.12 C) 0.13 D) 0.14 E) 0.15
Yes, Anonymous there are old people in this world. I took that course in 1955---uh---sorry, that's only 65 year ago AND that was in graduate school and I was in my mid-20s by then. That's 91+ by my arithmetic now and counting. As Bob Pursley says, "I'm older than dirt."
I used the formula Mass = Density x Volume, but the answers on the other numbers are not the same
This question has been posted numerous times over the last week or so. I have asked question about it but never received an answer. I'll try one more time.
Two questions:
1. For the Apparent burette reading of 10.05 and the others. I don't get it. What does "apparent burette reading" mean? How can 10.05, for example, be an apparent reading. It either read 10.05 or it didn't.
2. This looks like a question I dealt with in while in school about 70 years ago. It was all about air bouancy and how to calibrate a balance. We had to make corrections depending upon the weights; i.e., were they stainless, aluminum, bronze, etc. So what can you tell me about your class, the subject, what you are studying. what level, etc.
To find the true mass of water delivered, we need to calculate the difference between the apparent burette reading and the weight of water delivered.
To find the true volume of water delivered, we need to convert the true mass of water into volume using the density of water at the given temperature.
Now let's go through each question and find the answers step by step:
1. What is the true mass of water delivered in A?
First, subtract the apparent burette reading from the weight of water delivered:
True mass = Weight of water - Apparent burette reading
True mass = 10.03 g - 10.05 mL
True mass = 10.03 g
Therefore, the true mass of water delivered in A is 10.03 grams. The answer is A) 10.03.
2. What is the true mass of water delivered in B?
Using the same formula:
True mass = 20.09 g - 20.04 mL
True mass = 20.05 g
Therefore, the true mass of water delivered in B is 20.05 grams. The answer is not given in the options, but it is between 20.04 g and 20.06 g.
3. What is the true mass of water delivered in C?
True mass = 30.05 g - 30.08 mL
True mass = 29.97 g
Therefore, the true mass of water delivered in C is 29.97 grams. The answer is not given exactly in the options, but it is between 30.08 g and 29.96 g.
4. What is the true mass of water delivered in D?
True mass = 40.02 g - 40.07 mL
True mass = 39.95 g
Therefore, the true mass of water delivered in D is 39.95 grams. The answer is not given in the options, but it is between 40.06 g and 39.94 g.
5. What is the true volume of water delivered in A?
To find the true volume, we use the density of water at 19.0°C, which is 0.9984 g/mL.
True volume = True mass / Density of water
True volume = 10.03 g / 0.9984 g/mL
True volume = 10.05 mL
Therefore, the true volume of water delivered in A is 10.05 mL. The answer is C) 10.05.
6. What is the true volume of water delivered in B?
Using the same formula:
True volume = 20.05 g / 0.9984 g/mL
True volume = 20.08 mL
Therefore, the true volume of water delivered in B is 20.08 mL. The answer is not given exactly in the options, but it is between 20.06 mL and 20.10 mL.
7. What is the true volume of water delivered in D?
Using the same formula:
True volume = 39.95 g / 0.9984 g/mL
True volume = 40.01 mL
Therefore, the true volume of water delivered in D is 40.01 mL. The answer is not given in the options, but it is between 40.00 mL and 40.02 mL.
8. What is the true volume of water delivered in E?
The true volume of water delivered in E is simply the same as the apparent burette reading, which is 49.98 mL. The answer is B) 49.98.
9. What is the correction volume of water delivered in C?
Correction volume = Apparent burette reading - True volume
Correction volume = 30.08 mL - 29.97 mL
Correction volume = 0.11 mL
Therefore, the correction volume of water delivered in C is 0.11 mL. The answer is not given in the options, but it is between 0.10 mL and 0.12 mL.
10. What is the true volume of water delivered in D?
The true volume of water delivered in D is 40.01 mL, as calculated in question 7. The answer is not given in the options.
Please note that some of the answers are not provided in the options, but now you have the calculations to find the correct values.
You must be exaggerating, there is no way you are that old. I would have guess 20 or 30 years ago when you were in school.
It's not clear what apparent reading or true weight are. If the answers are posted that the author believes are the correct answwer, than maybe someone can help you figure out why the answer is what it is, or help you in understanding why the answer key is incorrect.