Question

The relative atomic mass of hydrogen is 1, and that of carbon is 12.

12 g of an unknown hydrocarbon (containing hydrogen and carbon only) was found to contain 9 g of carbon. This is shown below. What is the value of x?

Answer 1

The value of x in the hydrocarbon formula CxHy is 1.

Step-by-step explanation:

Here's how to arrive at the solution:

Since the relative atomic mass of carbon is 12 and the hydrocarbon contains 9g of carbon, we know that there are 9/12 = 0.75 moles of carbon in the hydrocarbon.

Since the hydrocarbon only contains hydrogen and carbon, the remaining mass (12g - 9g = 3g) must be due to hydrogen.

To find the number of moles of hydrogen, we need to convert the mass of hydrogen to moles. The relative atomic mass of hydrogen is 1, so the number of moles of hydrogen is 3/1 = 3 moles.

Therefore, the ratio of carbon to hydrogen in the hydrocarbon is 0.75 moles of carbon to 3 moles of hydrogen, which simplifies to 1:4.

The general formula for the hydrocarbon can be written as CxHy. Since the ratio of carbon to hydrogen is 1:4, we know that x = 1 and y = 4. Thanks.