Carbon dioxide gas, CO2(g), produced in the combustion of a...

Carbon dioxide gas, $\mathrm{CO}_{2}(\mathrm{g}),$ produced in the combustion of a sample of ethane is absorbed in $\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{aq})$ producing $0.506 \mathrm{g} \mathrm{BaCO}_{3}(\mathrm{s}) .$ How many grams of ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$ must have been burned? $\mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow$ $\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l})$ (not balanced) $\mathrm{CO}_{2}(\mathrm{g})+\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{aq}) \longrightarrow \mathrm{BaCO}_{3}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l})$.

Carbon dioxide gas, $\mathrm{CO}_{2}(\mathrm{g}),$ produced in the combustion of a sample of ethane is absorbed in $\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{aq})$ producing $0.506 \mathrm{g} \mathrm{BaCO}_{3}(\mathrm{s}) .$ How many grams of ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$ must have been burned?
$\mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow$
$\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l})$ (not balanced)
$\mathrm{CO}_{2}(\mathrm{g})+\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{aq}) \longrightarrow \mathrm{BaCO}_{3}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l})$.

Key Concepts

Gravimetric Analysis

Gravimetric analysis is a quantitative technique where an analyte is converted to a solid of known composition and its mass is measured. This method provides a direct means of determining the quantity of a substance based on the isolated mass of the product, linking the observed mass yield back to the original amounts of reactants.

Stoichiometry

Stoichiometry involves using the balanced chemical equation to determine the quantitative relationships between reactants and products. It allows for the conversion between amounts in moles, mass, or volume, providing a foundation for calculating unknown quantities from known masses or other measures.

Molar Mass Calculations

Molar mass calculations convert between the mass of a substance and the number of moles, serving as a bridge between laboratory measurements and theoretical chemical equations. This conversion is integral to stoichiometric calculations, allowing one to determine how much of a reactant or product is involved in a reaction.

Combustion Reactions

These reactions involve a substance reacting rapidly with oxygen to release energy and produce combustion products, frequently including carbon dioxide and water. Understanding combustion is essential to linking the consumption of a fuel with the formation of identifiable products that can be analyzed quantitatively.

Balanced Chemical Equations

Balancing chemical equations ensures that the number of atoms for each element is conserved across reactants and products, reflecting the law of conservation of mass. This process is critical for determining the precise mole ratios involved in reactions, which are then used in any quantitative analysis or calculation.

Transcript

00:01 We have here another sequence of reactions, and we're kind of working backwards because we're told we have 0 .506 grams of barium carbonate produced ultimately, and we want to know what mass of ethane do we have to combust to produce that.

00:20 So that's okay.

00:21 We'll just work backwards.

00:22 That's not a problem.

00:23 We need our molecular weight of barium carbonate is 1 .90.

00:31 7 .31 grams per mole.

00:36 And remember always our molecular weight is passed divided by number of moles.

00:45 So our number of moles here are just going to be our 0 .506 grams divided by 19 .197.

01:01 3 1 grams per mole.

01:09 And that's 2 .564 times 10 to the minus 3 moles.

01:22 Now we have to double check is this equation balance before we need to go any further.

01:27 1 barium, 1 barium, 1 carbon, 1 carbon.

01:32 We have 2 hydrogens, 2 hydrogens.