You drink a 12 oz beer that has 4.5% ABV. The rest of the calories, other than alcohol, come from carbohydrates. If the beer contains 140 calories, how many calories from carbohydrates did you ingest
The Correct Answer and Explanation is:
To calculate how many calories from carbohydrates you ingested, we first need to break down the total calories in the beer. The beer contains 140 calories, and we are told that the alcohol (ABV) contributes to some of these calories. The remaining calories come from carbohydrates.
Step 1: Calculate Calories from Alcohol
The alcohol content in the beer is 4.5% ABV. This means that 4.5% of the volume of the beer is pure alcohol. To find the calories from alcohol, we use the fact that one gram of ethanol (alcohol) contains approximately 7 calories.
Step 1a: Find the amount of alcohol in the beer.
- The beer is 12 oz, which is approximately 355 mL (since 1 oz ≈ 29.57 mL).
- 4.5% of the beer’s volume is alcohol, so: 355×0.045=15.975 mL of alcohol.355 \times 0.045 = 15.975 \, \text{mL of alcohol}.355×0.045=15.975mL of alcohol.
Step 1b: Convert alcohol volume to grams.
- The density of ethanol is about 0.789 g/mL. 15.975 mL×0.789 g/mL=12.61 g of alcohol.15.975 \, \text{mL} \times 0.789 \, \text{g/mL} = 12.61 \, \text{g of alcohol}.15.975mL×0.789g/mL=12.61g of alcohol.
Step 1c: Calculate calories from alcohol.
- Since each gram of alcohol provides 7 calories, the calories from alcohol are: 12.61 g×7=88.27 calories from alcohol.12.61 \, \text{g} \times 7 = 88.27 \, \text{calories from alcohol}.12.61g×7=88.27calories from alcohol.
Step 2: Calculate Calories from Carbohydrates
Now, we subtract the calories from alcohol from the total calories in the beer to find the calories from carbohydrates.
- Total calories = 140 calories
- Calories from alcohol = 88.27 calories 140−88.27=51.73 calories from carbohydrates.140 – 88.27 = 51.73 \, \text{calories from carbohydrates}.140−88.27=51.73calories from carbohydrates.
Conclusion
You ingested approximately 51.73 calories from carbohydrates in the beer.
