In the acetylene torch, acetylene gas (C2 H2) burns in oxygen to produce carbon dioxide, water,

In the acetylene torch, acetylene gas (C2 H2) burns in...

In the acetylene torch, acetylene gas $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$ burns in oxygen to produce carbon dioxide, water, and energy. $$ 2 \mathrm{C}_{2} \mathrm{H}_{2}(g)+5 \mathrm{O}_{2}(g) \stackrel{\Delta}{\longrightarrow} 4 \mathrm{CO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g) $$ a. How many moles of $\mathrm{O}_{2}$ are needed to react with $2.40 \mathrm{~mol}$ of $\mathrm{C}_{2} \mathrm{H}_{2} ?$ b. How many moles of $\mathrm{CO}_{2}$ are produced when $3.5 \mathrm{~mol}$ of $\mathrm{C}_{2} \mathrm{H}_{2}$ reacts? c. How many moles of $\mathrm{C}_{2} \mathrm{H}_{2}$ are required to produce $0.50 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{O}$ ? d. How many moles of $\mathrm{CO}_{2}$ are produced when $0.100 \mathrm{~mol}$ of $\mathrm{O}_{2}$ reacts?

In the acetylene torch, acetylene gas $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$ burns in oxygen to produce carbon dioxide, water, and energy.
$$
2 \mathrm{C}_{2} \mathrm{H}_{2}(g)+5 \mathrm{O}_{2}(g) \stackrel{\Delta}{\longrightarrow} 4 \mathrm{CO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g)
$$
a. How many moles of $\mathrm{O}_{2}$ are needed to react with $2.40 \mathrm{~mol}$ of $\mathrm{C}_{2} \mathrm{H}_{2} ?$
b. How many moles of $\mathrm{CO}_{2}$ are produced when $3.5 \mathrm{~mol}$ of $\mathrm{C}_{2} \mathrm{H}_{2}$ reacts?
c. How many moles of $\mathrm{C}_{2} \mathrm{H}_{2}$ are required to produce $0.50 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{O}$ ?
d. How many moles of $\mathrm{CO}_{2}$ are produced when $0.100 \mathrm{~mol}$ of $\mathrm{O}_{2}$ reacts?

Key Concepts

Conversion Factors

Conversion factors are numerical ratios based on the relationships provided in a balanced chemical equation. They allow for the conversion from moles of one chemical species to moles of another, facilitating the accurate determination of the amounts of reactants or products in a reaction.

Chemical Reaction Stoichiometry

Chemical reaction stoichiometry involves the quantitative relationships between reactants and products in a chemical reaction. By using the mole concept and the coefficients of a balanced equation, one can calculate the exact amounts of substances needed to react or be produced, ensuring that the law of conservation of mass is maintained.

Balanced Chemical Equations

A balanced chemical equation represents a chemical reaction where the number of atoms of each element is conserved. It provides the essential mole ratios between reactants and products, which are crucial for calculating the required or produced amounts of each substance during the reaction.

Mole Ratio Conversions

Mole ratio conversions are derived from the coefficients in a balanced chemical equation. They enable the conversion of a given amount of one substance into the corresponding amounts of other substances involved in the reaction, forming the basis for solving quantitative problems in stoichiometry.

Transcript

00:01 Okay, so in this question it is asking us about c2h2 gas being burned with oxygen to produce carbon dioxide, water, and energy.

00:13 And so the equation, the balanced equation that they give us is to c2h2 gas reacts with oxygen gas to form.

00:32 It's being burned, so there's heat, to form carbon.

00:37 Carbon, dioxide, gas, and water.

00:49 So this is our equation, and it's asking us in part a, that how many moles of oxygen are needed to react with 2 .4 moles of c2h2.

01:02 So starting off, we are given that 2 .4 moles of c2h2, and it wants us to know that how many moles of oxygen are needed and so we're basically going to have to make a one -mole factor to do that we're going to look at the balanced equation and we're relating our moles of c2 h2 and our moles of oxygen so we're going to use the coefficients given to us we're going to put our moles of c to h2 on the bottom since we want to be able to cancel these units out and our moles of oxygen is going to go on the top since that's what we want to end up with.

01:51 So these units will cancel out.

01:54 These moles of c2h2 will cancel out, and we will be left with the only unit we have, which is moles of oxygen.

02:01 So now we're just going to fill this in.

02:04 So we see two moles of c2h2.

02:07 I just grabbed that right from there, two moles and two moles, reacts with five moles of oxygen.

02:16 And so then we are given this multiple factor of 5 over 2.

02:20 And so to solve it, all we're going to do is 2 .4 times 5 over 2, or you could do 2 .4 times 5 divided by 2, whatever makes more sense in your head.

02:29 And doing that math, we get 6 moles of oxygen, which means that 6 moles of oxygen are needed to react fully with 2 .4 moles of c2h2 for this reaction.

02:45 In part b, they're asking us how many moles of carbon dioxide are produced when 3 .5 moles of c2h2 react.

02:51 So once again, we are starting off with moles of c2h2.

02:56 We have 3 .5.

03:03 And we are looking for moles of carbon dioxide.

03:09 And so that's the unit we're going to want.

03:11 So we're going to put that on top, moles of carbon dioxide, and moles of c2h2.

03:23 Okay.

03:24 And so once again, the moles of c2h2 are going to cancel out, leaving us with the moles of carbon dioxide, which is what we want.

03:34 That's what part b is asking us.

03:37 And so we see that moles of carbon dioxide, the coefficient is four.

03:43 So we have four moles of carbon dioxide and two moles of c2h2, just the coefficients from the equation.

03:52 And so to solve this, we would do 3 .5 times 4 over 2 or 3 .5 times 4 divided by 2...

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