Question

If there are 0.064g of theobromine in a 43g chocolate bar, how many moles of theobromine are there?

Answer 1

If the problem is finding the moles of theobromine, then the 43 g chocolate is not really a necessary information. All you have to do is convert 0.064 g of theobromine to moles using molar mass. The molar mass of theobromine is 180.164 g/mol. So,

0.064 g (1 mol / 180.164 g) = 3.6 x10^-4 moles

The answer would be letter A or the first choice :)

Answer 2

Answer:
`3.5* 10^(-4)`

Explanation:

To calculate the moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}`

Given mass of theobromine
`(C_7H_8N_4O_2)` = 0.064 g

Molar mass of theobromine
`(C_7H_8N_4O_2)=12* 7+1* 8+14* 4+16* 2=180 g`

`\text{Number of moles}=(0.064g)/(180g/mol)=3.5* 10^(-4)moles`