Determining the copper oxide used

  • Thread starter Bashyboy
  • Start date
  • Tags
    Copper
In summary, by examining the ratio of copper mass to total compound mass obtained (1.21/1.51), it can be determined that the oxide used was CuO.
  • #1
Bashyboy
1,421
5

Homework Statement


Oxides of copper include CuO and Cu2O. In a crucible, you heat 1.51 g of one of these copper oxides in the absence of air and obtain 1.21 g of pure Cu. Which oxide did you have?


Homework Equations





The Attempt at a Solution


I am really quite uncertain regarding how to even begin a problem like this.
 
Physics news on Phys.org
  • #2
Bashyboy said:

Homework Statement


Oxides of copper include CuO and Cu2O. In a crucible, you heat 1.51 g of one of these copper oxides in the absence of air and obtain 1.21 g of pure Cu. Which oxide did you have?

Homework Equations


The Attempt at a Solution


I am really quite uncertain regarding how to even begin a problem like this.

Chemistry has been a while for me, but I think you do this using simple ratios. Looking up the "standard atomic weight" of Oxygen, you get approximately 16 (rounding up). For copper, it's approx. 64 (again, rounding up). Let's say you broke up a single bond in the compound CuO, giving you one copper atom and one oxygen atom. The fraction of the total mass made up by copper would then be

(atomic weight of Cu)/(atomic weight of Cu + atomic weight of O)

The trick is that this is also the fraction of the total mass of the whole sample that you would expect to be in copper (since you'd get one copper atom for every oxygen atom). In contrast, for Cu2O, you'd get 2 copper atoms for every one oxygen atom, and the fraction of the total mass made up by copper would then be
(2*atomic weight of Cu)/(2*atomic weight of Cu + atomic weight of O)

So, assuming that heating the sample in a vacuum simply breaks the chemical bonds and gives you back the individual elements (which is the part I'm unsure about because I'm no chemist), then whichever one of these equations best matches the measured ratio of copper mass to total compound mass (1.21/1.51) tells you which compound you started with.
 
  • #3
cepheid said:
Let's say you broke up a single bond in the compound CuO, giving you one copper atom and one oxygen atom.

It is not a single bond actually - there are two bonds between copper and oxygen in CuO. But apart from that your idea about mass ratios is perfectly valid,
 

1. How do you determine the type of copper oxide used?

The type of copper oxide used can be determined through various analytical methods such as X-ray diffraction, infrared spectroscopy, and thermal gravimetric analysis. These techniques allow for the identification of the specific chemical composition and crystal structure of the copper oxide.

2. What is the purpose of determining the copper oxide used?

Determining the copper oxide used is important in understanding its properties and behavior, which can have significant implications in various fields such as materials science, chemistry, and environmental science. It can also aid in quality control and troubleshooting in industrial processes.

3. Can the copper oxide be determined through visual inspection?

No, visual inspection alone is not enough to determine the type of copper oxide used. While different types of copper oxide may have distinct colors, there are also other factors such as impurities or the presence of a coating that can affect the color. Therefore, analytical techniques are necessary for accurate identification.

4. Are there any safety precautions to consider when determining copper oxide?

Yes, safety precautions should always be taken when handling and analyzing copper oxide. This includes wearing appropriate personal protective equipment and following proper laboratory protocols to avoid exposure to potentially harmful substances.

5. Can the determination of copper oxide be affected by other factors?

Yes, other factors such as the method of preparation, storage conditions, and the presence of other compounds can affect the determination of copper oxide. Therefore, it is important to carefully consider these factors and choose the most suitable analytical technique for accurate results.

Similar threads

  • Biology and Chemistry Homework Help
Replies
3
Views
3K
  • Biology and Chemistry Homework Help
Replies
7
Views
9K
  • Biology and Chemistry Homework Help
Replies
10
Views
16K
  • Biology and Chemistry Homework Help
Replies
15
Views
3K
  • Biology and Chemistry Homework Help
Replies
3
Views
3K
  • Biology and Chemistry Homework Help
Replies
1
Views
15K
  • Biology and Chemistry Homework Help
Replies
16
Views
21K
  • Biology and Chemistry Homework Help
Replies
2
Views
9K
  • Biology and Chemistry Homework Help
Replies
6
Views
5K
  • Biology and Chemistry Homework Help
Replies
28
Views
8K
Back
Top