Podcast
Questions and Answers
What is the most abundant chemical substance in the universe?
What is the most abundant chemical substance in the universe?
At standard conditions, in what state is hydrogen?
At standard conditions, in what state is hydrogen?
How many protons, electrons, and neutrons does the most common isotope of hydrogen (symbol 1H) have?
How many protons, electrons, and neutrons does the most common isotope of hydrogen (symbol 1H) have?
Under what conditions does hydrogen become metallic?
Under what conditions does hydrogen become metallic?
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What role does hydrogen play in acid–base reactions?
What role does hydrogen play in acid–base reactions?
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What is the enthalpy of combustion for hydrogen gas?
What is the enthalpy of combustion for hydrogen gas?
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What is the autoignition temperature of hydrogen gas in air?
What is the autoignition temperature of hydrogen gas in air?
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What does the symbol H+ represent in ionic compounds?
What does the symbol H+ represent in ionic compounds?
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What type of flames do pure hydrogen-oxygen flames emit?
What type of flames do pure hydrogen-oxygen flames emit?
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How was hydrogen gas first artificially produced in the early 16th century?
How was hydrogen gas first artificially produced in the early 16th century?
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Study Notes
Hydrogen Facts
- Hydrogen is the most abundant chemical substance in the universe.
Physical Properties of Hydrogen
- At standard conditions, hydrogen is in a gaseous state.
Atomic Structure of Hydrogen
- The most common isotope of hydrogen (symbol 1H) has:
- 1 proton
- 1 electron
- 0 neutrons
Metallic Hydrogen
- Hydrogen becomes metallic under extremely high pressures, typically above 100 GPa.
Acid-Base Reactions
- Hydrogen plays a crucial role in acid-base reactions.
Combustion Properties of Hydrogen
- The enthalpy of combustion for hydrogen gas is -286 kJ/mol.
- The autoignition temperature of hydrogen gas in air is 500°C.
Ionic Compounds
- The symbol H+ represents a hydrogen ion in ionic compounds.
Hydrogen Flames
- Pure hydrogen-oxygen flames emit ultraviolet light, making them invisible.
History of Hydrogen Production
- Hydrogen gas was first artificially produced in the early 16th century through the reaction of acids with metals.
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Description
Test your knowledge of hydrogen, the chemical element with symbol H and atomic number 1. Learn about its properties as the lightest element, its abundance in the universe, and its existence in various states.
