There are 76 atoms in total
Answer:
84.24 g
Explanation:
Given data:
Mass of oxygen = 75 g
Mass of Al required to react = ?
Solution:
Chemical equation:
4Al + 3O₂ → 2Al₂O₃
Number of moles of oxygen:
Number of moles = mass/ molar mass
Number of moles = 75 g/ 32 g/mol
Number of moles = 2.34 mol
Now we will compare the moles of oxygen with Al.
O₂ : Al
3 : 4
2.34 : 4/3×2.34 = 3.12 mol
Mass of Al required:
Mass = number of moles × molar mass
Mass = 3.12 mol × 27 g/mol
Mass = 84.24 g
Answer:
(3) NaNO₃
Step-by-step explanation:
Sodium nitrate has ionic bonds, because it consists of Na⁺ and NO₃⁻ ions.
However, the nitrate ions have <em>covalent bonds</em> between the O atoms and the central N atoms.
(1) and (2) are <em>wrong</em>. Both N₂O₅ and HCl consist of nonmetals, so they are <em>covalent</em> compounds.
(4) is <em>wrong</em>. NaCl has <em>only ionic bonds</em> between the Na⁺ and Cl⁻ ions
<span>1. Blocks Ultra violet rays that can be harmful.
2. Provides Oxygen, so we can live.
3. It blocks meteors from hitting Earth's surface.
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