Problem 20 - Chemistry Matter and Change

Question

1.0 g of hydrogen reacts completely with 19.0 g of fluorine. What is the percent by mass of hydrogen in the compound that is formed?

Step-by-Step Solution

Answer

The percent by mass of hydrogen in the compound that is formed is 5%.

Step 1: Calculate the total mass of the compound

To find the total mass of the compound formed, we simply add the given masses of hydrogen and fluorine together. Total mass = mass of hydrogen + mass of fluorine Total mass = 1.0 g + 19.0 g

Step 2: Calculate the percent by mass of hydrogen

To find the percent by mass of hydrogen, we divide the mass of hydrogen by the total mass (found in Step 1) and multiply by 100%. Percent by mass of hydrogen = \(\frac{mass \ of \ hydrogen}{total \ mass}\) × 100% Calculating: Total mass = 1.0 g + 19.0 g = 20.0 g Percent by mass of hydrogen = \(\frac{1.0g}{20.0g}\) × 100% = 5% The percent by mass of hydrogen in the compound that is formed is 5%.

Key Concepts

Understanding the Mass of Hydrogen in Compounds

In the world of chemistry, hydrogen is an important element that frequently forms compounds with other elements. Here, we are specifically looking at how much hydrogen, by mass, exists in a new compound formed through a chemical reaction.
To identify the mass of hydrogen, we often start with a reaction where its mass is already given. In this exercise, you have 1.0 grams of hydrogen involved in the reaction.

• This known quantity allows us to determine how hydrogen contributes to the compound's total mass.
• Mass is a straight measurement, so ensuring accurate data from the start is crucial in precise calculations.

Hydrogen, being the lightest element, often contributes a smaller percentage when combined with heavier elements. Still, understanding its exact mass in compounds is vital for knowing the composition and behavior of these compounds.

Determining the Mass of Fluorine in Reactions

Fluorine is a highly reactive non-metal that readily forms compounds with hydrogen. In chemical reactions such as the one given in the problem, fluorine often comprises a more significant portion of the resulting compound's mass.
For the problem solved, fluorine's mass was already specified as 19.0 grams, showcasing its dominance in the mass composition of this particular reaction.

• Fluorine’s large mass relative to hydrogen greatly influences the compound's total mass.
• Using the known mass helps us calculate its percentage in the compound's total weight.

Fluorine's higher atomic mass compared to hydrogen means it often forms compounds where it significantly affects the overall properties such as the boiling or melting points. Knowing the mass of each participant in a reaction helps predict these properties.

Insights into Chemical Reactions and Compound Formation

Chemical reactions involve the transformation of reactants into products, and understanding these transformations is central to chemistry. Here, hydrogen reacts with fluorine.
Both elements combine to create a new compound, which can be perceived as a reorganisation of matter where the original substances cannot be restored easily.

• This leads to the creation of a new substance with distinct properties.
• The complete consumption of the reactants (hydrogen and fluorine) forms the product, with the masses adding up to the compound's total mass.

The reaction is an excellent example of conservation of mass, where the mass of the reactants equals the total mass of the product. Understanding these reactions helps in determining not just percent compositions but also provides insights into how and why certain compounds exhibit unique behaviors and characteristics.