The universe contains about 10 times as many hydrogen atoms as helium atoms, but a helium atom has 4 times the mass of a hydrogen atom. What is the approximate ratio of the universe's hydrogen to helium by mass?
A) 2.5 to 1
B) 10 to 1
C) 4 to 1
D) 1 to 4

Question

Quizplus · Accepted Answer

Given that there are about 10 hydrogen atoms for every helium atom and that a helium atom is 4 times as massive as a hydrogen atom, the mass ratio can be calculated as follows: For every 10 hydrogen atoms (10H), there is 1 helium atom (1He = 4H in mass). Therefore, the mass ratio of hydrogen to helium is 10H to 4H, which simplifies to 2.5 to 1.

The Universe Contains About 10 Times as Many Hydrogen Atoms