chem 203 - tutorial 1: stoichiometry and gas properties
part 1 - group activity (40 minutes)
total goals: use the ideal gas law to do stoichiometric calculations involving gases.
compare partial pressures, mole fractions, and total pressure in mixtures of gases.
determine and distinguish between average and instantaneous rates of reaction.
interpret graphs of concentration vs. time to compare rates.
additional skills reviewed: unit conversions, chemical formulas, stoichiometry, and significant digits
scenario 1: properties of gas mixtures
three containers are filled with different mixtures of neon and helium gases. all containers are kept at the same temperature.
legend: ● 1 mol of ne gas
○ 1 mol of he gas
1. rank these boxes according to each of the following properties, from lowest to largest. for each ranking, you should be able to explain your strategy or reasoning.
a. partial pressure of neon gas in each container
b. total pressure in each container
c. average density (defined as mass per unit volume) in the whole container
2. assuming that the temperature of the container is 100°c, calculate the partial pressure of neon (in kpa) in any one container. do you have all the information you need to complete this calculation?
a. if each group member calculated a different constant, what would you do to check your answer?
3. for the container you chose in question 2, what would/would not change in the container if 0.3 mol of ar gas was added to the container? explain your reasoning.
scenario 2: reactions of gas mixtures
sodium peroxide (na₂o₂) is used to eliminate carbon dioxide (co₂) build - up in airtight spaces such as submarines. the following (unbalanced) chemical reaction describes this process:
na₂o₂(s)+co₂(g)→na₂co₃(s)+o₂(g)
assume that the temperature and volume of the reaction container remain constant throughout the reaction, and that the solid products negligible volume of the flask.
1. balance the chemical equation above for the reaction of sodium peroxide and carbon dioxide.
2. suppose we add 3.00 moles of sodium peroxide to a 10.0 l empty container and 2.50 moles of co₂ gas, and we allow the reaction to complete at 350.0°c. what will be the final pressure in the flask?
3. which gas(es) will be present in the container at the end of the reaction? and in which quantity?
hint: which gas(es) will be present in the container at the end of the reaction?

Question

chem 203 - tutorial 1: stoichiometry and gas properties
part 1 - group activity (40 minutes)
total goals: use the ideal gas law to do stoichiometric calculations involving gases.
compare partial pressures, mole fractions, and total pressure in mixtures of gases.
determine and distinguish between average and instantaneous rates of reaction.
interpret graphs of concentration vs. time to compare rates.
additional skills reviewed: unit conversions, chemical formulas, stoichiometry, and significant digits
scenario 1: properties of gas mixtures
three containers are filled with different mixtures of neon and helium gases. all containers are kept at the same temperature.
legend: ● 1 mol of ne gas
○ 1 mol of he gas
1. rank these boxes according to each of the following properties, from lowest to largest. for each ranking, you should be able to explain your strategy or reasoning.
  a. partial pressure of neon gas in each container
  b. total pressure in each container
  c. average density (defined as mass per unit volume) in the whole container
2. assuming that the temperature of the container is 100°c, calculate the partial pressure of neon (in kpa) in any one container. do you have all the information you need to complete this calculation?
  a. if each group member calculated a different constant, what would you do to check your answer?
3. for the container you chose in question 2, what would/would not change in the container if 0.3 mol of ar gas was added to the container? explain your reasoning.
scenario 2: reactions of gas mixtures
sodium peroxide (na₂o₂) is used to eliminate carbon dioxide (co₂) build - up in airtight spaces such as submarines. the following (unbalanced) chemical reaction describes this process:
na₂o₂(s)+co₂(g)→na₂co₃(s)+o₂(g)
assume that the temperature and volume of the reaction container remain constant throughout the reaction, and that the solid products negligible volume of the flask.
1. balance the chemical equation above for the reaction of sodium peroxide and carbon dioxide.
2. suppose we add 3.00 moles of sodium peroxide to a 10.0 l empty container and 2.50 moles of co₂ gas, and we allow the reaction to complete at 350.0°c. what will be the final pressure in the flask?
3. which gas(es) will be present in the container at the end of the reaction? and in which quantity?
hint: which gas(es) will be present in the container at the end of the reaction?

Accepted Answer

# Explanation:
## Step1: Analyze gas mixture ranking in Scenario 1 - a
Partial pressure of a gas is proportional to its mole - fraction in the mixture. In container I, if we assume the total number of moles of gas is $n_{total1}$ and moles of Ne is $n_{Ne1}$, partial pressure of Ne $P_{Ne1}$ is related to mole - fraction $x_{Ne1}=\frac{n_{Ne1}}{n_{total1}}$ and total pressure $P_{total}$ by $P_{Ne1}=x_{Ne1}P_{total}$. Similarly for containers II and III.
## Step1: Analyze gas mixture ranking in Scenario 1 - b
Average density $
ho=\frac{m}{V}$, where $m$ is the total mass of the gas mixture and $V$ is the volume of the container. For Ne gas, we need to consider its mass in each container. If the molar mass of Ne is $M_{Ne}$, and moles of Ne in container $i$ is $n_{Nei}$, mass of Ne in container $i$ is $m_{Nei}=n_{Nei}M_{Ne}$.
## Step2: Solve for Scenario 2 - 1
The unbalanced reaction is $Na_2O_2(s)+CO_2(g)
ightarrow Na_2CO_3(s)+O_2(g)$. Balancing the equation:
We have 2 Na atoms on the left - hand side. For the Na atoms to be balanced on the right - hand side in $Na_2CO_3$, we start with the basic elements. The balanced chemical equation is $2Na_2O_2(s)+2CO_2(g)
ightarrow 2Na_2CO_3(s)+O_2(g)$.
## Step3: Solve for Scenario 2 - 2
First, use the ideal gas law $PV = nRT$. Given $V = 10.0L$, $n_{CO_2}=2.50mol$, $T=(350.0 + 273.15)K=623.15K$, and $R = 0.0821L\cdot atm/(mol\cdot K)$.
The initial pressure of $CO_2$ is $P_{CO_2}=\frac{n_{CO_2}RT}{V}$.
From the balanced equation $2Na_2O_2(s)+2CO_2(g)
ightarrow 2Na_2CO_3(s)+O_2(g)$, the mole ratio of $CO_2$ to $O_2$ is $2:1$.
If we add $n_{Na_2O_2}=3.00mol$ and $n_{CO_2}=2.50mol$, $CO_2$ is the limiting reactant. After the reaction, moles of $O_2$ produced $n_{O_2}=\frac{1}{2}n_{CO_2}$ (based on the stoichiometry of the reaction).
The total moles of gas after the reaction $n_{total}$ is the moles of $O_2$ produced. Then, using the ideal gas law again $P=\frac{n_{total}RT}{V}$ to find the final pressure.

Since the problem is incomplete (no specific questions about what values to find in some parts), we can't give a final numerical answer. But the general steps for solving gas - related and reaction - related problems are as above.

# Answer:
No specific final answer due to incomplete problem statement. General steps for solving are provided above.

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QUESTION IMAGE

Question

Explanation:

Step1: Analyze gas mixture ranking in Scenario 1 - a

Step1: Analyze gas mixture ranking in Scenario 1 - b

Step2: Solve for Scenario 2 - 1

Step3: Solve for Scenario 2 - 2

Answer: