The acetylene (C2 H2) used in welders' torches, burns...

The acetylene $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$ used in welders' torches, burns according to the following equation: $(9.2,9.3,9.5)$ $$ 2 \mathrm{C}_{2} \mathrm{H}_{2}(g)+5 \mathrm{O}_{2}(g) \stackrel{\Delta}{\longrightarrow} 4 \mathrm{CO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g) $$ a. What is the theoretical yield, in grams, of $\mathrm{CO}_{2}$, if $22.0 \mathrm{~g}$ of $\mathrm{C}_{2} \mathrm{H}_{2}$ completely reacts? b. If the actual yield in part a is $64.0 \mathrm{~g}$ of $\mathrm{CO}_{2}$, what is the percent yield of $\mathrm{CO}_{2}$ for the reaction?

The acetylene $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$ used in welders' torches, burns according to the following equation: $(9.2,9.3,9.5)$
$$
2 \mathrm{C}_{2} \mathrm{H}_{2}(g)+5 \mathrm{O}_{2}(g) \stackrel{\Delta}{\longrightarrow} 4 \mathrm{CO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g)
$$
a. What is the theoretical yield, in grams, of $\mathrm{CO}_{2}$, if $22.0 \mathrm{~g}$ of $\mathrm{C}_{2} \mathrm{H}_{2}$ completely reacts?
b. If the actual yield in part a is $64.0 \mathrm{~g}$ of $\mathrm{CO}_{2}$, what is the percent yield of $\mathrm{CO}_{2}$ for the reaction?

Key Concepts

Balanced Chemical Equation

A balanced chemical equation provides the correct stoichiometric ratios of reactants and products in a chemical reaction. It is essential for determining the relationships between the substances involved, ensuring that mass is conserved during the reaction.

Stoichiometry

Stoichiometry involves using the quantitative relationships inherent in a balanced chemical equation to calculate the amounts of reactants needed or products formed. It requires converting between mass and moles using molar masses and applying the mole ratios from the equation.

Molar Mass and Mole Concept

The mole concept is a fundamental principle in chemistry that provides a way to count entities at the atomic or molecular scale using the unit 'mole'. Molar mass, which is the mass of one mole of a substance, allows conversion between the measured mass of a substance and the amount in moles, facilitating stoichiometric calculations.

Theoretical Yield

The theoretical yield is the maximum amount of product that can be generated from given quantities of reactants, assuming complete conversion with no losses. It is computed using stoichiometric relationships derived from the balanced chemical equation.

Percent Yield

Percent yield is a metric used to evaluate the efficiency of a chemical reaction. It is calculated by dividing the actual yield of the product by the theoretical yield, then multiplying by 100 to express the result as a percentage.

Transcript

00:01 Okay, so this is a limiting reactant problem.

00:03 I know that because i'm being given amounts of both reactants.

00:08 Okay, so 175 grams of c2h2 and 175 grams of o2.

00:16 So let's go ahead and figure out how much co2 we would make in each case.

00:23 And then whichever one gives less, then we'll know that's our limiting reactant.

00:30 So just kind of setting up the backbone here.

00:32 I'm going to change grams of c2h2 to moles of c2h2, and then we'll get our mole ratio going here, moles of co2, and then we'll get grams of co2.

00:46 So one mole here is 26 .04.

00:51 Our mole ratio is 4 to 2, and 44 .01.

00:57 So 59, sorry, 592 grams of co2 if c2h2 is our limiting reactant.

01:10 So let's see how much we'd get from our oxygen.

01:15 Again, just setting up our backbone here of our dimensional analysis, changing 02 to moles of o2, got our mole ratio, moles of co2.

01:30 So o2 is 32 .02.

01:34 32 .00 because it's diatomic.

01:37 Our ratio is 4 to 5 and this is still 44 .01.

01:44 So this gives us 193 grams of co2.

01:48 So this is our, this is the amount of co2 we make and our o2 is our limiting reactant and this is in excess.

02:03 So let's see if we can find our percent yield...