Final answer:
There are approximately 1071 joules in a 255 calorie snack bar.
Step-by-step explanation:
The conversion between a joule and a calorie is approximately 4.2 joules = 1 calorie. So, to convert the 255 calories in the snack bar to joules, you can use the conversion factor:
255 calories x 4.2 joules/calorie = 1071 joules
Therefore, there are approximately 1071 joules in a 255 calorie snack bar.