A. Thermal Expansion
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Answer:
4.28x10^24 molecules
Explanation:
From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules. From the above, we understood that 1mole of H2O also contains 6.02x10^23 molecules.
1mole of H2O = (2x1) + 16 = 2 + 16 = 18g
Now, if 18g of H2O contains 6.02x10^23 molecules,
Then 128g of H2O will contain = (128x 6.02x10^23) /18 = 4.28x10^24 molecules
Answer:
2.4 moles of oxygen are needed to react with 87 g of aluminium.
Explanation:
Chemical equation:
4Al(s) + 3O₂(l) → 2AlO₃(s)
Given data:
Mass of aluminium = 87 g
Moles of oxygen needed = ?
Solution:
Moles of aluminium:
Number of moles of aluminium= Mass/ molar mass
Number of moles of aluminium= 87 g/ 27 g/mol
Number of moles of aluminium= 3.2 mol
Now we will compare the moles of aluminium with oxygen.
Al : O₂
4 : 3
3.2 : 3/4×3.2 = 2.4 mol
2.4 moles of oxygen are needed to react with 87 g of aluminium.
<span>1.61 × 1023 Multiply by 26.8 to get the answer.161.33 x 10 ^23 </span>
