a) To name five substances that contain organic molecules, we need to understand what organic molecules are. Organic molecules are compounds that primarily consist of carbon atoms bonded with other elements such as hydrogen, oxygen, nitrogen, sulfur, and others. Here are five substances that contain organic molecules:
1. Glucose: It is a simple sugar found in many fruits and forms an essential source of energy for living organisms.
2. Ethanol: It is the alcohol found in alcoholic beverages and is also used as a biofuel.
3. Propane: It is a hydrocarbon used as a fuel for heating and cooking.
4. DNA: It is a molecule that carries genetic instructions and is found in the cells of all organisms.
5. Cholesterol: It is a lipid molecule found in animal cells and plays a crucial role in cell membrane structure and hormone production.
b) To name two chemists who were involved in the history of organic chemistry but not mentioned in this lesson, we can consider some prominent figures:
1. Friedrich Wöhler: He is known for synthesizing urea, a naturally occurring organic compound, in 1828. This experiment challenged the belief that organic compounds could only be derived from living organisms, opening the door to the field of synthetic organic chemistry.
2. Emil Fischer: He made significant contributions to the understanding of carbohydrates and proteins. Fischer developed techniques for synthesizing complex organic compounds and was awarded the Nobel Prize in Chemistry in 1902.
c) Hydrocarbons consist of only two elements: carbon (C) and hydrogen (H). These compounds exclusively contain carbon and hydrogen atoms and form the basis of organic chemistry.
d) Hydrocarbons on Earth have various sources, including:
1. Fossil Fuels: Oil, natural gas, and coal are derived from the remains of ancient living organisms. Over millions of years, these remains have undergone geological processes such as heat and pressure, converting organic matter into hydrocarbon-rich deposits.
2. Biomass: Organic materials such as wood, crop waste, and other plant-based matter contain hydrocarbons. By converting this biomass through processes like pyrolysis or fermentation, hydrocarbons can be obtained.
3. Methane from Methanogenic Bacteria: Methanogenic bacteria found in environments like marshes, wetlands, and digestive systems of animals produce methane gas through biological processes.
To name three sources of hydrocarbons, we consider these examples. However, it's important to note that hydrocarbons can have various sources and occur naturally in different forms on Earth.