Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

When potassium cyanide ( \(\mathrm{KCN}\) ) reacts with acids, a deadly poisonous gas, hydrogen cyanide (HCN), is given off. Here is the equation: $$ \mathrm{KCN}(a q)+\mathrm{HCl}(a q) \longrightarrow \mathrm{KCl}(a q)+\mathrm{HCN}(g) $$ If a sample of \(0.140 \mathrm{~g}\) of \(\mathrm{KCN}\) is treated with an excess of \(\mathrm{HCl}\), calculate the amount of HCN formed, in grams.

Short Answer

Expert verified
The mass of HCN formed is approximately 0.0581 g.

Step by step solution

01

Calculate the molar mass of KCN

First, determine the molar mass of KCN. The atomic masses are: K = 39.1, C = 12.0, and N = 14.0. Add these together to get the molar mass of KCN:\[39.1 + 12.0 + 14.0 = 65.1\text{ g/mol}\]
02

Convert grams of KCN to moles

Use the molar mass of KCN to convert 0.140 g of KCN to moles:\[\text{moles of KCN} = \frac{0.140}{65.1} \approx 0.00215 \text{ moles}\]
03

Use stoichiometry to find moles of HCN

From the balanced equation, the molar ratio of KCN to HCN is 1:1. Therefore, the moles of HCN produced is the same as the moles of KCN initially:\[\text{moles of HCN} = 0.00215 \text{ moles}\]
04

Calculate the mass of HCN formed

Determine the molar mass of HCN. The atomic masses are: H = 1.0, C = 12.0, and N = 14.0. Add these together:\[1.0 + 12.0 + 14.0 = 27.0 \text{ g/mol}\]Use the moles of HCN to find the grams of HCN:\[\text{mass of HCN} = 0.00215 \times 27.0 \approx 0.0581 \text{ g}\]

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Chemical Reactions
Chemical reactions are processes where substances, known as reactants, transform into different substances, called products. In the reaction given, potassium cyanide (KCN) reacts with hydrochloric acid (HCl) to produce potassium chloride (KCl) and hydrogen cyanide (HCN), a gas that has toxic properties.

In this process, atoms are rearranged but not created or destroyed. This particular reaction is an example of a single replacement reaction, where an element in a compound is replaced by an element in another compound.

Understanding the type of reaction occurring helps in predicting the products and the behavior of the substances involved. It also provides insight into the safety precautions needed, especially when dealing with dangerous chemicals.
Molar Mass Calculation
Molar mass is a fundamental concept in chemistry, referring to the mass of one mole of a given substance. It provides a bridge between the atomic scale and the bulk measurements in the laboratory.

To calculate the molar mass of \( \text{KCN} \), we sum the atomic masses of its constituent elements: potassium (K), carbon (C), and nitrogen (N).
  • Potassium: 39.1 g/mol
  • Carbon: 12.0 g/mol
  • Nitrogen: 14.0 g/mol
Adding these gives us a total molar mass: \( 39.1 + 12.0 + 14.0 = 65.1 \text{ g/mol} \). This value is crucial for converting between grams and moles, enabling precise stoichiometric calculations, which are essential for predicting how much of each product is formed in reactions.
Balanced Chemical Equations
Balanced chemical equations are vital for accurately representing chemical reactions. They ensure the conservation of mass, which means the same number of each type of atom is present in both the reactants and products.

In the equation \( \text{KCN} (aq) + \text{HCl} (aq) \rightarrow \text{KCl} (aq) + \text{HCN} (g) \), each molecule of KCN reacts with a molecule of HCl to produce one molecule each of KCl and HCN.

The balanced equation reflects a 1:1 molar ratio between the reactants and products, crucial for stoichiometric calculations. This ratio tells us that for every mole of KCN consumed, one mole of HCN is produced.
  • This ensures that the equation respects the law of conservation of mass and predicts yields of products.
  • Understanding this allows chemists to calculate the amounts of reactants needed or products formed and apply these skills effectively in laboratory settings or industry processes.
Balancing equations is not just an academic exercise; it’s an essential skill in chemistry used to ensure reactions proceed as desired.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

When combined, aqueous solutions of sulfuric acid and potassium hydroxide react to form water and aqueous potassium sulfate according to the following equation (unbalanced): $$ \mathrm{H}_{2} \mathrm{SO}_{4}(a q)+\mathrm{KOH}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{K}_{2} \mathrm{SO}_{4}(a q) $$ Determine what mass of water is produced when a beaker containing \(100.0 \mathrm{~g} \mathrm{H}_{2} \mathrm{SO}_{4}\) dissolved in \(250 \mathrm{~mL}\) water is added to a larger beaker containing \(100.0 \mathrm{~g}\) KOH dissolved in \(225 \mathrm{~mL}\) water. Determine the mass amounts of each substance (other than water) present in the large beaker when the reaction is complete.

Define limiting reactant and excess reactant. What is the significance of the limiting reactant in predicting the amount of the product obtained in a reaction? Can there be a limiting reactant if only one reactant is present?

Platinum forms two different compounds with chlorine. One contains 26.7 percent \(\mathrm{Cl}\) by mass, and the other contains 42.1 percent \(\mathrm{Cl}\) by mass. Determine the empirical formulas of the two compounds.

Lysine, an essential amino acid in the human body, contains \(\mathrm{C}, \mathrm{H}, \mathrm{O},\) and \(\mathrm{N}\). In one experiment, the complete combustion of \(2.175 \mathrm{~g}\) of lysine gave \(3.94 \mathrm{~g}\) \(\mathrm{CO}_{2}\) and \(1.89 \mathrm{~g} \mathrm{H}_{2} \mathrm{O} .\) In a separate experiment, \(1.873 \mathrm{~g}\) of lysine gave \(0.436 \mathrm{~g} \mathrm{NH}_{3}\). (a) Calculate the empirical formula of lysine. (b) The approximate molar mass of lysine is \(150 \mathrm{~g}\). What is the molecular formula of the compound?

A die has an edge length of \(1.5 \mathrm{~cm}\). (a) What is the volume of one mole of such dice? (b) Assuming that the mole of dice could be packed in such a way that they were in contact with one another, forming stacking layers covering the entire surface of Earth, calculate the height in meters the layers would extend outward. [The radius \((r)\) of Earth is \(6371 \mathrm{~km}\), and the area of a sphere is \(4 \pi r^{2}\).]

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free