A student placed 12.5 g of glucose (C6H12O6) in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the 100. mL mark on the neck of the flask was reached. The flask was then shaken until the solution was uniform. A 60.0 mL sample of this glucose solution was diluted to 0.500 L. How many grams of glucose are in 100. mL of the final solution?

Express your answer to three significant figures and include the appropriate units.

# Hellllppppp, having a hard time with chemistry question!!! its simple, I just dont know what to do?

- Posted:
- 3+ months ago by badatchem
- Topics:
- water, simple, student, chemistry, question, swirling, time, glucose

## Answers (2)

1. Find the amount of glucose = 12.5/Mr of glucose. I got 0.0694mol. This is the same amount of glucose in 100ml in the flask.

2. Find the amount of glucose in 60ml = 60/100 x 0.0694. I got 0.0416mol. This is the same amount of glucose in 500ml (0.500L) diluted solution.

3. Hence in 100ml of 500ml diluted solution, there will be 100/500 x 0.0416 = 0.00832mol.

4. Find the mass = amount of glucose x Mr of glucose. 0.00832 x 180 = 1.50g.

Hoped I got the right answer tried my best to explain!

And sorry if the terms and method I used are different we probably have different education systems.

12.5g dispersed in [something]. 60% of that = 7.5g and dispersed in [something]. 1/5 of 7.5g = 1.5g <-- ANSWER

Get a ruler in your hands. Measure things until you start to understand how a ruler works. Measure some stuff and figure out where the center is. Say you measure a book and it's 7/8" thick. You look at your ruler and see that every eighth is divided into two sixteenths, so obviously half of 7/8" is going to be 7/16". If you write that out you have 1/2 x 7/8 = 7/16. And you notice that 1/2 is divided into 2/4 and then into 4/8 and so on, so you can convert anything to anything by multiplying all the numbers on top and then all the numbers on bottom.

Other rulers are divided into 10 and 100 parts. But an inch is still an inch, so anything on one ruler can be translated to the other ruler. A half inch on one ruler is 5/10 or 50/100 on the other. An eighth inch is just 12.5 marks when you have 100 marks per inch. A metric ruler divides an inch into 25.4 parts, so a half inch would be 12.7 of those parts. Pretty simple, isn't it? Practice this a bit and people will think you went to wizard school.