Question

If there are 2 x 10^22 C-atoms in a sample of ethane, C2H6, how many hydrogen atoms are there in that same sample?

a) 6 x 10^22
b) 12 x 10^22
c) 3 x 10^22
d) 9 x 10^22

Answer 1

To find the number of hydrogen atoms in the sample of ethane, calculate the number of moles of ethane and use the mole ratio between ethane and hydrogen. The correct answer is (b) 12 x 10^22.

Step-by-step explanation:

To find the number of hydrogen atoms in the sample of ethane, we need to calculate the number of moles of ethane and use the mole ratio between ethane and hydrogen.

Given that there are 2 x 10^22 C-atoms in the sample of ethane, we can convert this to moles by dividing by Avogadro's number (6.02 x 10^23). So, the number of moles of ethane is (2 x 10^22) / (6.02 x 10^23) = 3.32 x 10^-2 moles.

Since each mole of ethane contains 6 moles of hydrogen, the number of hydrogen atoms in the sample is 3.32 x 10^-2 moles of ethane × 6 moles of hydrogen = 1.99 x 10^-1 moles of hydrogen. Converting this to atoms, we multiply by Avogadro's number: (1.99 x 10^-1) × (6.02 x 10^23) = 1.20 x 10^23 hydrogen atoms. Therefore, the correct answer is (b) 12 x 10^22.