1. Elements are ordered by their properties.
2. The symbol is Si. Elemental symbols have no more than 2 letters(except for unidentified elements), and only the first letter is capitalized.
3. All atoms of an element are alike.
4. Metals are shiny and can conduct. They are found on the left side of the periodic table.
5. The most recent model is the Electron Cloud model, or the Schrödinger model.
6. Nonmetals are dull and don’t conduct.
7. MULTIPLE elements conjoin to form compounds. If all the atoms are the same, it’s still an element.
8. I can’t see the picture, sorry.
9. In order for a reaction to take place, energy must be present. This can be in the form of heat, though, but it’s not universal.
10. Enzymes are catalysts that speed up chemical reactions.
Answer:
0.59 moles
Explanation:
Data Given
oxygen = 35 g
Moles of SeO₃ = ?
Reaction Given
2Se + 3O₂ ------> 2SeO₃
Solution:
Step 1.
First to find grams of SeO₃
So, we know from reaction that 2 mole of selenium combine with 3 mole of oxygen and produces 2 mole of SeO₃
2Se + 3O₂ ------> 2SeO₃
2mol 3 mol 2 mol
If we represent mole in grams
Then,
Molar mass of Se = 79 g/mol
Molar mass of O = 16 g/mol
Molar mass of SeO₃ = 79 + 3(16)
Molar mass of SeO₃ = 127 g/mol
2Se + 3O₂ ------> 2SeO₃
2mol (79 g/mol) 3 mol (32 g/mol) 2 mol (127 g/mol)
2Se + 3O₂ ------> 2SeO₃
158 g 96 g 206 g
It is obvious from the reaction that 96 g of oxygen gives 206 g of SeO₃.
Now how many grams of SeO₃ will produce if 35 grams of oxygen react with excess of Selenium
Apply unity formula
96 g of O₂ ≅ 206 g of SeO₃
35 g of O₂ ≅ x g of SeO₃
By doing cross multiplication
g of SeO₃ = 206 x 35 / 96
g of SeO₃ = 75 g
Step 2.
Convert grams of SeO₃ to mole
Formula used
no. of moles = mass in grams (SeO₃) / Molar mass of SeO₃
Put values in above formula
no. of moles = 75 g / 127 g/mol
no. of moles = 0.59 mol
So,
35 g of oxygen produces 0.59 moles of SeO₃
Destructive interference in which waves cancel each other out is depicted in region X,Y and Z.
<u>Explanation:</u>
Interface is the particle property of light waves. When incident light beam is made to pass through holes, the waves will combine either constructively or destructively. Constructive interference means the waves having same phase will get added so they will increase in amplitude. While destructive interference means the waves combining have different phases like crests and troughs. So they undergo decrease or complete vanishing of amplitude.
When waves combine in constructive interference, they form bright white light and when they combine in destructive interference, they form dark black light. So the regions X, Y and Z are shown as dark black colors in the diagram, so these regions represent destructive interference in which waves cancel each other out.