A scientist has 42.359 grams of copper. She uses 3.08 grams in an experiment. How many grams of copper
A 38.559 grams
B. 11.559 grams
C. 39.279 grams
D. 42.051 grams
The correct answer and explanation is:
The correct answer is A. 38.559 grams.
To find the amount of copper remaining, you need to subtract the amount used in the experiment from the initial amount available.
Start by subtracting 3.08 grams from 42.359 grams: 42.359 grams−3.08 grams=38.559 grams42.359 \, \text{grams} – 3.08 \, \text{grams} = 38.559 \, \text{grams}
So, the scientist has 38.559 grams of copper left after using 3.08 grams in the experiment.
This is a simple subtraction problem. The key here is to ensure the correct alignment of decimal points when performing the operation. After performing the subtraction, you get the result with the same decimal precision as the numbers you started with. In this case, both numbers had three decimal places, so the result also has three decimal places.
Understanding this concept of subtraction is important in scientific calculations, especially when dealing with precise measurements. It ensures that the final result reflects the accuracy of the initial measurements. In laboratory work, even small differences in measurements can be significant, so it is essential to handle units and decimal points carefully.
This process also highlights the importance of paying attention to significant figures. The number of decimal places in the answer should reflect the precision of the given values.