Question

Find the average number of hydrogen molecules per cubic centimeter if there are $8\times {10}^{12}$ hydrogen molecules in a volume of $4\times {10}^4$ cubic centimeters.

• A. $5\times {10}^{-9}$
• B. $2\times {10}^3$
• C. $2\times {10}^8$
• D. $32\times {10}^{16}$
• E. $32\times {10}^{48}$

Answer 1

The correct option is C $2\times {10}^8$

Thus the required concentration is $=\frac{8\times {10}^{12}}{4\times {10}^4}=2\times {10}^{12-4}=2\times {10}^8$.