When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 25.2g of carbon were burned in the presence of 78.0g of oxygen, 10.8g of oxygen remained unreacted. What mass of carbon dioxide was produced?

Thus, oxygen must the the limiting reagent.

C + O2 ==> CO2
78.0 g O2 to start
remaining is 10.8; therefore,
78.0-10.8 = 67.2 g oxygen consumed.
That is 67.2/32 = ?moles.
?mols O2 x (1 mole CO2/1 mole O2) = ?moles CO2.
grams CO2 = moles CO2 x molar mass CO2.

92.4gCO2

To find the mass of carbon dioxide produced, we can use the concept of conservation of mass.

1. Write down the balanced chemical equation for the reaction:
C + O2 -> CO2

2. Calculate the moles of carbon used:
Moles of carbon = mass of carbon / molar mass of carbon
The molar mass of carbon = 12.01 g/mol
moles of carbon = 25.2g / 12.01 g/mol

3. Calculate the moles of oxygen used:
Moles of oxygen used = moles of carbon used (since the ratio of carbon to oxygen is 1:1 in the balanced equation)

4. Calculate the moles of oxygen remaining:
Moles of oxygen remaining = Total moles of oxygen - Moles of oxygen used
Total moles of oxygen = mass of oxygen / molar mass of oxygen
The molar mass of oxygen = 16.00 g/mol
Total moles of oxygen = 78.0g / 16.00 g/mol
Moles of oxygen remaining = Total moles of oxygen - Moles of oxygen used = (78.0g / 16.00 g/mol) - (moles of carbon used)

5. Calculate the moles of carbon dioxide produced:
Moles of carbon dioxide = Moles of carbon = moles of carbon used

6. Calculate the mass of carbon dioxide produced:
Mass of carbon dioxide = moles of carbon dioxide * molar mass of carbon dioxide
The molar mass of carbon dioxide = 44.01 g/mol
Mass of carbon dioxide = moles of carbon dioxide * 44.01 g/mol

Now let's calculate step by step:

Molar mass of carbon = 12.01 g/mol
Moles of carbon used = 25.2g / 12.01 g/mol

Moles of oxygen used = Moles of carbon used = moles of carbon used

Molar mass of oxygen = 16.00 g/mol
Total moles of oxygen = 78.0g / 16.00 g/mol
Moles of oxygen remaining = (total moles of oxygen) - (moles of carbon used)

Moles of carbon dioxide = moles of carbon used
Molar mass of carbon dioxide = 44.01 g/mol
Mass of carbon dioxide = moles of carbon dioxide * 44.01 g/mol

Now we can plug in the values and calculate:

Moles of carbon used = 25.2g / 12.01 g/mol = 2.10 moles

Moles of oxygen used = Moles of carbon used = 2.10 moles

Total moles of oxygen = 78.0g / 16.00 g/mol = 4.88 moles

Moles of oxygen remaining = (total moles of oxygen) - (moles of carbon used) = 4.88 moles - 2.10 moles = 2.78 moles

Moles of carbon dioxide = moles of carbon used = 2.10 moles

Mass of carbon dioxide = moles of carbon dioxide * 44.01 g/mol = 2.10 moles * 44.01 g/mol = 92.22g

Therefore, the mass of carbon dioxide produced is 92.22g.

To find the mass of carbon dioxide produced, we need to determine the amount of oxygen consumed during the reaction.

1. Calculate the amount of oxygen consumed:
The initial amount of oxygen is 78.0g, and the remaining amount is 10.8g. So, the amount of oxygen consumed is:
78.0g - 10.8g = 67.2g

2. Convert the amount of consumed oxygen to the amount of carbon dioxide produced:
The balanced chemical equation for the combustion of carbon in air is:
C + O2 → CO2

According to the equation, 1 mole of carbon reacts with 1 mole of oxygen to produce 1 mole of carbon dioxide. The molar mass of oxygen is 32 g/mol, and the molar mass of carbon dioxide is 44 g/mol.

To convert grams of oxygen to moles of carbon dioxide, we can use the molar mass of oxygen:
Moles of oxygen = Grams of oxygen / Molar mass of oxygen
Moles of oxygen = 67.2g / 32 g/mol = 2.1 mol

Since the balanced equation shows a 1:1 ratio between oxygen and carbon dioxide, the moles of carbon dioxide produced can be calculated as:
Moles of carbon dioxide = Moles of oxygen = 2.1 mol

3. Convert moles of carbon dioxide to grams:
To convert moles of carbon dioxide to grams, we can use the molar mass of carbon dioxide:
Mass of carbon dioxide = Moles of carbon dioxide × Molar mass of carbon dioxide
Mass of carbon dioxide = 2.1 mol × 44 g/mol = 92.4g

Therefore, the mass of carbon dioxide produced is 92.4 grams.