Classify the following as chemical or physical property:
A Hemoglobin gives blood its red color.
B Beryllium, in powder form, burns brilliantly on ignition.
C Mercury is liquid at room temperature.
D Copper is a good conductor of electricity.
E Magnesium metal does not react with cold water.
The correct answer and explanation is:
Let’s go through each one:
A. Hemoglobin gives blood its red color
Physical Property
The red color of blood is a characteristic that arises from how light is absorbed and reflected by hemoglobin molecules. This is a physical property because it does not involve a change in the chemical structure of the substance. The color can be observed without altering the molecular composition of hemoglobin.
B. Beryllium, in powder form, burns brilliantly on ignition
Chemical Property
The ability of beryllium powder to burn when ignited involves a chemical change, as it reacts with oxygen to form a new compound. This change in composition signifies a chemical property.
C. Mercury is liquid at room temperature
Physical Property
Mercury being liquid at room temperature is a physical property because it refers to its state of matter at a given temperature. The property involves no chemical transformation and only describes a physical characteristic.
D. Copper is a good conductor of electricity
Physical Property
Copper’s ability to conduct electricity is a physical property. It refers to the metal’s electrical conductivity, which is due to the movement of electrons within the material, and does not involve any chemical change in the substance.
E. Magnesium metal does not react with cold water
Chemical Property
The fact that magnesium metal does not react with cold water indicates its chemical stability in that specific environment. Chemical properties describe how a substance interacts with other substances, and in this case, the lack of a reaction is a chemical property.
Summary:
- A (Red color of hemoglobin) and C (Mercury being liquid at room temperature) are physical properties, as they relate to the appearance or state of a substance.
- B (Beryllium burning) and E (Magnesium not reacting) are chemical properties, as they describe how the substance interacts or reacts with other substances.
- D (Copper conducting electricity) is a physical property related to the material’s ability to transmit electricity without changing its chemical makeup.