Question

When a piece of magnesium ribbon weighing \(0.32 \mathrm{~g}\) is burned in oxygen, the resultant oxide weighs \(0.53 \mathrm{~g}\). What is the percentage composition of the oxide?

Short answer

The percentage composition of the magnesium oxide is 60.4% magnesium and 39.6% oxygen.

Step-by-step solution

Calculate the mass of oxygen

We'll start by finding the mass of oxygen that has combined with the magnesium ribbon. To do this, subtract the initial mass of the magnesium from the final mass of the oxide. Mass of oxygen = mass of oxide - mass of magnesium Mass of oxygen = 0.53 g - 0.32 g

Compute for the mass of oxygen

Now, calculate the mass of oxygen as follows: Mass of oxygen = 0.53 g - 0.32 g = 0.21 g

Calculate the percentage composition of magnesium

Now, we will find the percentage composition of magnesium in the oxide. Divide the mass of magnesium by the total mass of the oxide (0.53 g) and then multiply by 100 to get the percentage: Percentage composition of magnesium = (mass of magnesium / mass of oxide) * 100 Percentage composition of magnesium = (0.32 g / 0.53 g) * 100

Compute for the magnesium's percentage

Now, calculate the percentage composition of magnesium as follows: Percentage composition of magnesium = (0.32 g / 0.53 g) * 100 = 60.4%

Calculate the percentage composition of oxygen

Finally, we will find the percentage composition of oxygen in the oxide. Divide the mass of oxygen by the total mass of the oxide (0.53 g) and then multiply by 100 to get the percentage: Percentage composition of oxygen = (mass of oxygen / mass of oxide) * 100 Percentage composition of oxygen = (0.21 g / 0.53 g) * 100

Compute for the oxygen's percentage

Now, calculate the percentage composition of oxygen as follows: Percentage composition of oxygen = (0.21 g / 0.53 g) * 100 = 39.6% Now, we have the percentage composition of magnesium and oxygen in the oxide, which is 60.4% for magnesium and 39.6% for oxygen.

Key concepts

Magnesium Oxide

Magnesium oxide is a chemical compound made up of magnesium and oxygen elements. When magnesium burns in the presence of oxygen, it forms this compound. In our exercise, magnesium is in the form of a solid piece or ribbon, which when exposed to heat in oxygen-rich surroundings, reacts with the oxygen to create magnesium oxide. This is seen as a bright white light, and the resulting substance is a white powdery compound.
Magnesium oxide is often used in several applications such as in ceramics, fertilizers, and as a supplement for magnesium. Its chemical formula is represented as \( \text{MgO} \). Each magnesium atom pairs with one oxygen atom to form this stable compound. The entire process is efficient and simple, making magnesium oxide a commonly studied example in chemistry.

Mass Calculation

Mass calculation in chemistry helps us understand how much of each element is present in a compound. It is a key part of stoichiometry - the branch of chemistry that deals with the quantitative aspects of chemical reactions. In our problem, when the magnesium ribbon was burned, its initial mass was given as \(0.32\, \text{g}\), and once it turned into magnesium oxide, the final mass of the compound was \(0.53\, \text{g}\).
To find out the mass of oxygen that reacted with magnesium, you subtract the mass of magnesium from the mass of magnesium oxide:

• Mass of oxygen = Mass of oxide - Mass of magnesium.
• So, \(0.53\, \text{g} - 0.32\, \text{g} = 0.21\, \text{g}\).

This gives us the mass of oxygen that combined with magnesium during the reaction. Mass calculation can also extend to determining the percentage composition of elements in a compound, as shown in subsequent steps.

Chemical Reactions

Chemical reactions involve the transformation of substances through a reorganization of atoms. In our exercise, burning magnesium in oxygen was a prime example. Here's how the reaction goes: magnesium ( Mg ) + oxygen ( O_2 ) yields magnesium oxide ( MgO ).
This is a simple combination reaction where two different elements react to form a compound. During this reaction, the magnesium atoms donate electrons to the oxygen atoms, and a strong ionic bond forms between them in the magnesium oxide compound.
Understanding this process is crucial for calculating the percentage composition. It involves knowing what actually reacts and how much product is formed. This gives insight into how materials combine and perform in different chemical processes. These principles are critical, not just in laboratory experiments, but also in industrial applications where precise chemical compositions are needed to produce the desired product.