Human body composition: Which element is present in the highest proportion (~65% by mass) in the human body? Consider overall elemental composition by mass in an average adult. Choose the correct option.

Q: Human body composition: Which element is present in the highest proportion (~65% by mass) in the human body? Consider overall elemental composition by mass in an average adult. Choose the correct option.

Concept/Approach The body is ~60% water by mass, and tissues contain oxygen-rich compounds; thus oxygen is ~65% by mass, more than carbon, hydrogen, or nitrogen. Final Answer Oxygen

Difficulty: Easy

Carbon
Hydrogen
Oxygen
Nitrogen

Correct Answer: Oxygen

Explanation:

Concept/Approach
The body is ~60% water by mass, and tissues contain oxygen-rich compounds; thus oxygen is ~65% by mass, more than carbon, hydrogen, or nitrogen.

Final Answer
Oxygen

← Previous Question Next Question→

More Questions from Chemistry

Stoichiometry (composition of CO₂): How many moles of CO₂ contain 16 g of oxygen? Use the fact that each mole of CO₂ contains 32 g of oxygen (two O atoms). Choose the correct value.
Bond character comparison: Among the hydrogen halides (HI, HF, HCl, HBr), which molecule exhibits the highest percentage of ionic character? Use the concept of electronegativity difference between hydrogen and the halogen to infer relative ionic character. Choose the correct option.
Earth materials (origin of oldest rocks): The earliest rocks formed when molten magma from deep within the young Earth erupted and solidified. Name the rock type produced by the cooling and crystallization of magma (e.g., from volcanic eruptions). Choose the correct option.
Reactivity of metals with dilute acids: Which metal among the following does not liberate hydrogen gas on treatment with dilute HCl? Use the metal activity series relative to hydrogen. Choose the correct option.
Nuclear forces (binding the nucleus): Which nuclear particles mediate the strong force that holds nucleons together in older (Yukawa) models? Focus on the historical concept of force carriers inside the nucleus. Choose the correct option.
Ore identification (iron): Magnetite is an important iron ore—select its correct chemical formula from the options provided. Match the common name ‘‘magnetite’’ with its standard oxide formula. Choose the correct option.
Acid–base species: Identify the hydronium ion among the following chemical species. Recall that hydronium is protonated water (the actual carrier of ‘‘H⁺’’ in aqueous solution). Choose the correct option.
Atomic numbers vs mass numbers: The mass number (A) of an atom equals what count of subatomic particles? Relate A to the composition of the nucleus (protons and neutrons). Choose the correct option.
Indian mineral resources: Which ore is found in abundance in India compared to the other options listed? Consider well-known placer deposits and strategic reserves in India. Choose the correct option.
Applied X-ray detection: Which of the following items is particularly amenable to detection by soft X-rays (lower energy, higher absorption by light elements)? Consider penetration and contrast for organic materials. Choose the correct option.

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion