Answer:
The percent by mass of copper in the mixture was 32%
Explanation:
The ammount of HNO₃ used is:
mol HNO₃ = volume * concentration
mol HNO₃ = 0.015 l * 15.8 mol/l
mol HNO₃ = 0.237 mol
According to the reaction, 4 mol HNO₃ will react with 1 mol Cu and produce 1 mol Cu²⁺. Since we have 0.237 mol HNO₃, the amount of Cu that could react would be (0.237 mol HNO₃ * 1 mol Cu / 4 mol HNO₃) 0.06 mol. This reaction would produce 0.060 mol Cu²⁺, however, only 0.010 mol Cu²⁺ were obtained, indicating that only 0.010 mol Cu were present in the mixture. This means that the acid was in excess, so we can assume that all copper present in the mixture has reacted.
Since 0.010 mol of Cu²⁺ were produced, the amount of Cu was 0.01 mol.
1 mol of Cu has a mass of 63.5 g, then 0.01 mol has a mass of:
0.01 mol Cu * 63.5 g / 1 mol = 0.635 g.
Since this amount was present in 2.00 g mixture, the amount of copper in 100 g of the mixture will be:
100 g(mixture) * 0.635 g Cu / 2 g(mixture) = 32 g
Then, the percent by mass of Cu (which is the mass of Cu in 100 g mixture) is 32%
Answer:
It allows the completion of the metamorphosis of the silkworm to its moth stage, whereas most silk harvesting requires the silkworms to be killed in their cocoon stage. No animals suffer or die for the silk to be produced, making it a favorable alternative to normal silk for those who do not believe in harming animals.
Answer:
15.5g
Explanation:
"The total mass of both chemicals and the containers they are in is 15.5 g." After a chemical reaction, by conservation of mass, the total mass of the products and the two containers after reaction is the same at 15.5g.
Clockwise from the carbon connected to three H atoms:
- C: sp³
- N: sp³
- C: sp³
- C: sp²
- N: sp².
<h3>Explanation</h3>
Start by finding the number of electron domains on each C and N atom. Why the number of electron domains? The number of electron domains of an atom indicates it hybridization. For atoms in period two (which includes both C and N):
- An atom with four electron domains is sp³ hybridized.
- An atom with three electron domains is sp² hybridized.
- An atom with two electron domains is sp hybridized.
How many electron domains on each of the atoms?
For each atom:
- Each atom that the atom in question is connected to (via covalent bonds, for sure) counts towards one electron domain. This rule shall hold for bonds of all orders. (i.e., No matter if the the two atoms are connected via a Single bond, a double bond, or a triple bond.) In other words, each C-C or C-N single bond counts towards one electron domain. Each C=N double bond also counts towards one electron domain.
- Each lone pair on the atom in question counts towards one electron domain. Keep in mind that there are two electrons in one lone pair. (Hence the name "pair".)
For example:
- The carbon atom at the bottom of the graph is connected to four other atoms- three Hs and one N. There's no lone pair on that atom. That C atom contains four electron domains, which implies that the atom is sp³ hybridized.
- The nitrogen atom near the right end of the molecule is connected to two other atoms- one C and one H. There's one lone pair on that molecule. 2 + 1 = 3. That N atom contains three electron domains, which implies that the atom is sp² hybridized.
Try to figure out the number of electron domains on the rest of the atoms. Then determine their hybridization. In conclusion, clockwise from the carbon connected to three H atoms:
- C: sp³
- N: sp³
- C: sp³
- C: sp²
- N: sp².