Phosgene Inhalation: HCl Mass Calculation In Lungs

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Hey guys! Today, we're diving into a chemistry problem that's not just theoretical but has real-world implications. We're going to figure out how much hydrochloric acid (HCl) forms in the lungs when someone inhales phosgene, a toxic gas. This is a classic stoichiometry problem, so let's break it down step by step. Understanding the chemical reactions in our body when exposed to hazardous substances is super important, and this example illustrates exactly that. Let's get started and make sure we understand every detail!

Understanding the Problem

So, the big question we're tackling is: If a person inhales 198 mg of phosgene (COCl₂), what mass of hydrochloric acid (HCl) will form in their lungs? We've got some atomic masses to help us out: Carbon (C) = 12, Oxygen (O) = 16, Chlorine (Cl) = 35.5, and Hydrogen (H) = 1. To nail this, we'll need to: 1) write out the balanced chemical equation, 2) convert the mass of phosgene to moles, 3) use the stoichiometry of the reaction to find moles of HCl produced, and 4) convert moles of HCl back to grams. It sounds like a lot, but trust me, it’s totally manageable once we break it down. We need to ensure that we're on the same page about what's happening chemically, so let's get to the equation!

1. Write the Balanced Chemical Equation

First things first, we need to know what's going on chemically. Phosgene reacts with water in the lungs to produce hydrochloric acid and carbon dioxide. So, the unbalanced equation looks like this:

COCl₂ + H₂O → HCl + CO₂

Now, let’s balance it. We can see that we have two chlorine atoms on the left (in COCl₂) and only one on the right (in HCl). To balance the chlorine, we'll need two molecules of HCl. This also balances the hydrogen atoms. The balanced equation is:

COCl₂ + H₂O → 2 HCl + CO₂

This balanced equation is crucial because it tells us the molar relationship between phosgene and hydrochloric acid. For every 1 mole of phosgene that reacts, we get 2 moles of hydrochloric acid. This is the key ratio we'll use later to convert moles of phosgene to moles of HCl. Now that we have the balanced equation, we can move on to figuring out how many moles of phosgene we're dealing with. Remember, stoichiometry is all about these mole ratios, so getting this right is a big win!

2. Convert Mass of Phosgene to Moles

To figure out how many moles of phosgene (COCl₂) we have, we need its molar mass. We can calculate this using the atomic masses given:

Molar mass of COCl₂ = 1 × Carbon + 1 × Oxygen + 2 × Chlorine = (1 × 12) + (1 × 16) + (2 × 35.5) = 12 + 16 + 71 = 99 g/mol

Now that we know the molar mass, we can convert the given mass of phosgene (198 mg) to grams and then to moles. First, convert milligrams to grams:

198 mg × (1 g / 1000 mg) = 0.198 g

Next, use the molar mass to convert grams to moles:

Moles of COCl₂ = 0.198 g / 99 g/mol = 0.002 moles

So, we have 0.002 moles of phosgene. This is a critical step because we need moles to use the stoichiometry from our balanced equation. If we had stopped at grams, we wouldn't be able to correctly relate the amount of phosgene to the amount of hydrochloric acid produced. Think of moles as the common currency in the world of chemical reactions – it allows us to compare different substances on an equal footing.

3. Use Stoichiometry to Find Moles of HCl Produced

Here's where the balanced equation really shines! Remember, our balanced equation is:

COCl₂ + H₂O → 2 HCl + CO₂

This tells us that 1 mole of COCl₂ produces 2 moles of HCl. We've already calculated that we have 0.002 moles of COCl₂. Now, we can use the stoichiometric ratio to find the moles of HCl produced:

Moles of HCl = Moles of COCl₂ × (2 moles HCl / 1 mole COCl₂) = 0.002 moles COCl₂ × 2 = 0.004 moles HCl

See how straightforward that was? The balanced equation acted like a recipe, telling us exactly how much HCl we'd get from our starting amount of phosgene. It's like knowing that if you bake one cake (COCl₂), you'll need to double the frosting recipe (2 HCl). Stoichiometry, guys, is all about these proportions. Now that we know the moles of HCl produced, we're just one step away from our final answer: converting those moles into grams.

4. Convert Moles of HCl to Grams

Alright, we're in the home stretch! We know we have 0.004 moles of HCl, and now we need to convert that to grams. To do this, we'll use the molar mass of HCl. Let's calculate it:

Molar mass of HCl = 1 × Hydrogen + 1 × Chlorine = (1 × 1) + (1 × 35.5) = 1 + 35.5 = 36.5 g/mol

Now, we can convert moles of HCl to grams:

Mass of HCl = Moles of HCl × Molar mass of HCl = 0.004 moles × 36.5 g/mol = 0.146 g

So, if someone inhales 198 mg of phosgene, 0.146 grams of hydrochloric acid will form in their lungs. That's our final answer! We took a seemingly complex problem and broke it down into manageable steps. We identified the key information, wrote the balanced equation, converted masses to moles, used stoichiometry, and finally converted moles back to mass. This is the essence of solving stoichiometry problems, and you nailed it!

Final Answer

The mass of hydrochloric acid formed in the lungs is 0.146 grams. Therefore, the correct answer is:

b) 1.46 x 10⁻Âč g

Wrapping Up

We did it! We successfully calculated the mass of hydrochloric acid formed from phosgene inhalation. Remember, the key to these problems is breaking them down into smaller, more manageable steps. Always start with a balanced equation, convert to moles, use the stoichiometric ratios, and then convert back to the desired units. Chemistry can seem daunting, but with a methodical approach, you can tackle even the trickiest problems. Keep practicing, and you'll become a stoichiometry pro in no time! You got this, guys!