The volume of CO₂ at STP = 2.8 L
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Further explanation
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Given
21 gram of sodium hydrogen carbonate-NaHCO₃
Required
Volume of CO₂
Solution
The decomposition of sodium bicarbonate into sodium carbonate, carbon dioxide, and water :
2 NaHCO₃(s) → Na₂CO₃(s) + CO₂(g) + H₂O(g)
mol of NaHCO₃ :
= mass : MW NaHCO₃
= 21 g : 84 g/mol
= 0.25
From the equation, mol ratio of NaHCO₃(s) :CO₂(g) = 2 : 1, so mol CO₂ :
= 1/2 x mol NaHCO₃
= 1/2 x 0.25
= 0.125
At STP, 1 mol gas = 22.4 L, so for 0.125 mol :
= 0.125 x 22.4 L
= 2.8 L
<u>Answer:</u> The number of gold atoms per cubic centimeters in the given alloy is 
<u>Explanation:</u>
To calculate the number of gold atoms per cubic centimeters for te given silver-gold alloy, we use the equation:
where,
= number of gold atoms per cubic centimeters
= Avogadro's number = 
= Mass percent of gold in the alloy = 42 %
= Density of pure gold = 
= Density of pure silver = 
= molar mass of gold = 196.97 g/mol
Putting values in above equation, we get:
Hence, the number of gold atoms per cubic centimeters in the given alloy is
Photosynethesis, respiration, and combustion.
The formula for determining the moles of a compound is grams (g) divided by molecular weight (MW), or moles = g / MW. The molecular formula of oxygen gas is O₂, and because each oxygen atom possesses an atomic weight of 16.00 grams per mole (g/mol) (this value is found on the Periodic Table), the MW of oxygen gas is 32.00 g/mol. Therefore, 32 g of oxygen gas represent (32 g) / (32.00 g/mol) = 1.0 moles of O₂.<span>Source(s):
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