I'm stuck on this one problem in Chemistry:
A student measures the mass of an object as 2.32 grams and its volume as 34.56mL. The student then calculates the density to be 0.067129629. There are two things wrong with the students value for density. What are they?
Now when I calculated it. I got the same answer and I can't figure out how there are two things wrong with it. Does anyone else know????
Significant digits, and no units specified are two things that strike me quickly.
To identify the two things wrong with the student's value for density, let's start by reviewing the formula for density:
Density = mass / volume
Given that the student measured the mass as 2.32 grams and the volume as 34.56 mL, they calculated the density to be 0.067129629. Let's check if this value is correct.
First, divide the mass by the volume:
Density = 2.32 g / 34.56 mL
To perform this calculation, convert the volume from milliliters to grams since they need to have the same units. To do this, you need to know the density of the substance being measured. Assuming it's water, the density is approximately 1 g/mL.
Volume in grams = 34.56 mL * 1 g/mL = 34.56 g
Now you can calculate the density:
Density = 2.32 g / 34.56 g = 0.067099415
The calculated density is approximately 0.067099415, which is slightly different from the student's value of 0.067129629.
The two mistakes in the student's calculation could be:
1. Rounding error: The student's calculated value, 0.067129629, might be rounded incorrectly. Instead, it should be rounded to the appropriate number of decimal places or significant figures, depending on the instructions or the accuracy of the measuring instruments.
2. Significant figures: The student's calculated value has more decimal places than the measurements provided. Based on the given measurements, both the mass and volume have four significant figures. Therefore, the density should also be reported with four significant figures, giving a value of 0.0671.
By checking the calculations and considering significant figures, you can determine that the student's value for density has two mistakes: a rounding error and incorrect use of significant figures.