Answer:
Formula weight of H₂O molecule is 18.02 amu.
Explanation:
Given data:
Formula weight of H₂O = ?
Atomic mass of H = 1.008 amu
Atomic mass of O = 16.00 amu
Solution:
Formula weight:
"It is the sum of all the atomic weight of atoms present in given formula"
Formula weight of H₂O = 2×1.008 amu + 1×16.00 amu
Formula weight of H₂O = 18.02 amu
Thus, formula weight of H₂O molecule is 18.02 amu.
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Answer:
Option A.
2Na + 2H2O —> 2NaOH + H2
Explanation:
To know which option is correct, we shall do a head count of the number of atoms present on both side to see which of them is balanced. This is illustrated below below:
For Option A:
2Na + 2H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
4 H >>>>>>>>>>>> 4 H
2 O >>>>>>>>>>>> 2 O
Thus, the above equation is balanced.
For Option B:
2Na + 2H2O —> NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 3 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced.
For Option C:
2Na + H2O —> 2NaOH + H2
Reactant >>>>>>> Product
2 Na >>>>>>>>>>> 2 Na
2 H >>>>>>>>>>>> 4 H
1 O >>>>>>>>>>>> 2 O
Thus, the above equation is not balanced.
For Option D:
Na + 2H2O —> NaOH + 2H2
Reactant >>>>>>> Product
1 Na >>>>>>>>>>> 1 Na
4 H >>>>>>>>>>>> 5 H
2 O >>>>>>>>>>>> 1 O
Thus, the above equation is not balanced.
From the illustrations made above, only option A is balanced.
Answer:
C) 3.3 x 104 grams
Explanation:
1 mole of water contains 6.02 × 10^23 atoms
1.1 × 10^27 atoms will contain;
1.1 × 10^27 ÷ 6.02 × 10^23
= 0.1827 × 10^( 27 - 23)
= 0.1827 × 10^(4)
= 1.827 × 10³ moles of water.
To convert mole to mass in grams, we use the formula;
mole (n) = mass (m) ÷ molar mass (MM)
Molar mas of water (H2O) = 1(2) of H + 16 of O = 18g/mol
mole = mass/molar mass
1.827 × 10³ = mass / 18
mass = 1.827 × 10³ × 18
mass = 32.886 × 10³
mass = 3.286 × 10⁴
mass = 3.3 × 10⁴ grams
