Question

Label the following statements about the world's largest gold bar as quantitative or qualitative observations. (This gold bar was worth approximately \(\$ 10.25\) million in 2013.) (a) The melting point of gold is \(1064.2^{\circ} \mathrm{C}\). (b) The volume of the gold bar is \(15,730 \mathrm{~cm}^{3}\). (c) Gold metal is a conductor of electricity. (d) The mass of the gold bar is \(250 \mathrm{~kg}\). (e) The gold bar is yellow and shiny.

Short answer

Quantitative: (a), (b), (d); Qualitative: (c), (e).

Step-by-step solution

Define Quantitative Observations

Quantitative observations are observations that relate to quantities or numbers. These observations include data that can be measured or counted, such as mass, volume, temperature, and numerical values.

Define Qualitative Observations

Qualitative observations are those that describe properties or characteristics that do not include numerical measurements. These observations describe qualities, such as colors, shapes, and physical states.

Identify Observation (a)

The melting point of gold is given as a specific temperature: \(1064.2^{\circ} \mathrm{C}\). This is a numerical value, so it is a quantitative observation.

Identify Observation (b)

The volume of the gold bar is \(15,730 \mathrm{~cm}^{3}\), which is a numerical measurement. Thus, this is a quantitative observation.

Identify Observation (c)

Gold metal being a conductor of electricity describes a property or characteristic without using numerical values. Therefore, it is a qualitative observation.

Identify Observation (d)

The mass of the gold bar is \(250 \mathrm{~kg}\), which consists of a numerical value. This makes it a quantitative observation.

Identify Observation (e)

The description of the gold bar as yellow and shiny refers to its color and sheen, which are characteristics without numerical measurement. Thus, it is a qualitative observation.

Key concepts

Quantitative Observations

Quantitative observations involve measurements and numerical data. They quantify an object's properties using numbers. For example, when you measure temperature, you are making a quantitative observation. This type of observation is essential in scientific research because numbers provide precise data that can be analyzed mathematically. In the context of the gold bar, when we mention that it has a mass of \(250 \mathrm{~kg}\) or its volume is \(15,730 \mathrm{~cm}^{3}\), we are making quantitative observations. These numbers help us define the specific physical attributes of the gold bar exactly, making it easier to compare with other objects or materials.

Qualitative Observations

Qualitative observations describe characteristics or properties that are not numerical. They refer to qualities such as color, texture, scent, taste, and appearance. These observations are crucial because they provide contextual information that may not be captured through numbers alone. For instance, saying the gold bar is yellow and shiny captures its appearance, which can be significant in understanding its aesthetic or market value. Qualitative observations are often used alongside quantitative ones to provide a comprehensive description of an object.

Properties of Gold

Gold is a precious metal known for several key properties that make it valuable in various applications, from jewelry to electronics. Some essential properties include:

• Malleability: Gold can be hammered into thin sheets without breaking.
• Ductility: It can be drawn into thin wires, which is useful in electronics.
• Conductivity: As indicated in the exercise, gold is an excellent conductor of electricity, which enhances its use in electrical components.
• Color and Luster: Its distinct yellow color and shine make it appealing for aesthetic purposes.
• Resistance to Tarnish: Gold does not react with most chemicals, meaning it doesn't tarnish over time, preserving its appearance.

These properties contribute to gold's high economic value and utility in technology and art.

Measurement in Chemistry

Measurement in chemistry is crucial for understanding the composition and properties of substances. It involves quantifying different aspects of a material, allowing chemists to make precise calculations and reliable predictions. Typically, measurements in chemistry are recorded using various units, depending on what is being measured, such as:

• Mass: Measured in grams (g) or kilograms (kg).
• Volume: Commonly measured in liters (L) or cubic centimeters (cm³).
• Temperature: Usually measured in degrees Celsius (°C) or Kelvin (K).
• Concentration: Expressed as moles per liter (mol/L) for solutions.

These measurements ensure that scientific observations and experiments are accurate and reproducible, forming a foundational aspect of chemical research and industry applications.