Iron And HCl Reaction: Products & Volume At STP

Hey guys! Today, we're diving into a classic chemistry problem involving the reaction between iron and hydrochloric acid. This is a super common type of question you might see in your chemistry class, so let's break it down step by step to make sure we all understand what's going on.

The Reaction: $Fe(s) + 2HCl(aq) \rightarrow FeCl_2(aq) + H_2(g)$

Before we get started, let's write out the chemical reaction to make sure we are on the same page:

$Fe(s) + 2HCl(aq) \rightarrow FeCl_2(aq) + H_2(g)$

The Basics of the Reaction

This equation tells us that solid iron ($Fe$) reacts with hydrochloric acid ($HCl$) in an aqueous solution to produce iron(II) chloride ($FeCl_2$), which is also in an aqueous solution, and hydrogen gas ($H_2$). The question states that we're adding 30.0 mL of 1.00 M $HCl$ to 0.56 g of powdered $Fe$. Our goal is to figure out how much hydrogen gas is produced when this reaction goes to completion, assuming we're at 273 K and 1.0 atm.

Step 1: Calculate Moles of Reactants

First, we need to figure out how many moles of each reactant we have. This will help us determine the limiting reactant and how much product we can form.

• Moles of $HCl$:

  We have 30.0 mL of 1.00 M $HCl$. Remember that Molarity (M) is defined as moles per liter. So, we can calculate the moles of $HCl$ as follows:

  $$Moles$$

otag HCl = Volume otag (L) \times Molarity $

Convert mL to L: 30.0 mL = 0.030 L

$
Moles 

otag HCl = 0.030 otag L \times 1.00 otag M = 0.030 otag moles $

• Moles of $Fe$:

  We have 0.56 g of $Fe$. To find the moles, we'll use the molar mass of $Fe$, which is approximately 55.85 g/mol.

  $$$$

Moles otag Fe = \frac{Mass otag (g)}{Molar otag Mass otag (g/mol)} $

$

Moles otag Fe = \frac{0.56 otag g}{55.85 otag g/mol} \approx 0.010 otag moles $

Step 2: Determine the Limiting Reactant

Now we need to figure out which reactant will limit the amount of product formed. Looking back at the balanced equation:

$Fe(s) + 2HCl(aq) \rightarrow FeCl_2(aq) + H_2(g)$

We see that 1 mole of $Fe$ reacts with 2 moles of $HCl$. Let's see how much $HCl$ we need to react completely with the $Fe$ we have:

$$Moles otag HCl otag needed = Moles otag Fe \times 2 = 0.010 otag moles \times 2 = 0.020 otag moles$$

We have 0.030 moles of $HCl$, but we only need 0.020 moles to react with all the $Fe$. This means $Fe$ is the limiting reactant, and $HCl$ is in excess.

Step 3: Calculate Moles of $H_2$ Produced

Since $Fe$ is the limiting reactant, the amount of $H_2$ produced will be based on the moles of $Fe$ we started with. According to the balanced equation, 1 mole of $Fe$ produces 1 mole of $H_2$. Therefore:

$$Moles otag H_2 otag produced = Moles otag Fe = 0.010 otag moles$$

Step 4: Calculate the Volume of $H_2$ Gas at STP

We're given that the reaction occurs at 273 K and 1.0 atm. These conditions are known as Standard Temperature and Pressure (STP). At STP, 1 mole of any gas occupies 22.4 L. Therefore, we can calculate the volume of $H_2$ gas produced as follows:

$$Volume otag H_2 = Moles otag H_2 \times Volume otag per otag mole otag at otag STP$$

$$Volume otag H_2 = 0.010 otag moles \times 22.4 otag L/mol = 0.224 otag L$$

To convert this to mL, we multiply by 1000:

$$Volume otag H_2 = 0.224 otag L \times 1000 otag mL/L = 224 otag mL$$

The Final Answer

So, when the reaction is complete at 273 K and 1.0 atm, 224 mL of $H_2$ gas is produced.

Key Concepts Recap

Alright, let's make sure we've nailed down the key steps and concepts from this problem. Understanding these will help you tackle similar chemistry questions with confidence.

Moles Calculation

The foundation of many stoichiometry problems is converting grams or volumes into moles. Remember these formulas:

• Moles from grams:

  $$$$

Moles = \frac{Mass otag (g)}{Molar otag Mass otag (g/mol)} $

• Moles from Molarity and Volume:

  $$$$

Moles = Molarity \times Volume otag (L) $

Limiting Reactant

The limiting reactant is the substance that is completely consumed in the reaction. It determines the maximum amount of product that can be formed. To find the limiting reactant:

1. Calculate the moles of each reactant.
2. Use the balanced equation to find the mole ratio between the reactants.
3. Determine which reactant will run out first based on the mole ratio.

Stoichiometry

Stoichiometry is the study of the quantitative relationships between reactants and products in chemical reactions. The balanced chemical equation is the key to understanding these relationships. For example, in our reaction:

$Fe(s) + 2HCl(aq) \rightarrow FeCl_2(aq) + H_2(g)$

1 mole of $Fe$ reacts with 2 moles of $HCl$ to produce 1 mole of $FeCl_2$ and 1 mole of $H_2$.

Ideal Gas Law and STP

At Standard Temperature and Pressure (STP), which is 273 K and 1.0 atm, 1 mole of any gas occupies 22.4 L. This is a useful conversion factor for gas stoichiometry problems.

Extra Tips for Chemistry Success

1. Always Balance Equations: Make sure your chemical equation is balanced before doing any calculations. This ensures that the mole ratios are correct.
2. Pay Attention to Units: Keep track of your units and make sure they cancel out correctly in your calculations. Converting mL to L or grams to moles is crucial.
3. Practice, Practice, Practice: The more you practice stoichiometry problems, the better you'll become at recognizing patterns and applying the concepts.

Real-World Applications

Understanding reactions like this isn't just for acing your chemistry test. They have practical applications in various fields:

• Industrial Chemistry: Many industrial processes involve reactions between metals and acids. For example, pickling steel (removing surface impurities) often uses hydrochloric acid.
• Environmental Science: Understanding chemical reactions helps in treating industrial waste and reducing pollution.
• Corrosion: The reaction between iron and acids is a key part of understanding corrosion, which is a major concern in construction and manufacturing.

So next time you see rust on a car or a bridge, remember it's just a chemical reaction gone wild!

Alright, hope this breakdown helps you guys understand the reaction between iron and hydrochloric acid a little better. Keep practicing, and you'll be a chemistry whiz in no time!