Question

applying scientific methods
a chemistry student is given the task of analyzing three unknown samples. her data is listed in data table 1. use data table 1 to answer the questions below.
data table 1

	sample a		sample b		sample c
1	80.72	10.01	95.41	10.72	72.28	10.00
2	80.64	10.00	92.33	10.51	72.32	9.99
3	80.91	10.05	93.78	10.62	72.34	9.95
avg	80.76	10.02	93.84	10.62	72.30	9.98

1. based on the data given, what is the density of each sample? follow the rules for significant figures and rounding for your answers. show your work

sample a
sample b
sample c

1. compare the data for each trail and each sample in data table 1. which sample(s) did the student measure precisely? explain your answer.

Explanation:

Step1: Recall density formula

Density $
ho=\frac{m}{V}$, where $m$ is mass and $V$ is volume.

Step2: Calculate density of Sample A

$
ho_A=\frac{80.76}{10.02}\approx8.06\ g/mL$

Step3: Calculate density of Sample B

$
ho_B=\frac{93.84}{10.62}\approx8.84\ g/mL$

Step4: Calculate density of Sample C

$
ho_C=\frac{72.30}{9.98}\approx7.24\ g/mL$

for question 39:
Precision refers to the closeness of repeated - measurements to each other. For Sample A, the mass values are 80.72, 80.64, 80.91 and volumes are 10.01, 10.00, 10.05. The values are relatively close. For Sample B, the mass values 95.41, 92.33, 93.78 and volumes 10.72, 10.51, 10.62 have a bit more spread. For Sample C, the mass values 72.28, 72.32, 72.34 and volumes 10.00, 9.99, 9.95 are also relatively close. Samples A and C have more consistent measurements in terms of mass and volume across the trials.

Answer:

Sample A: $8.06\ g/mL$
Sample B: $8.84\ g/mL$
Sample C: $7.24\ g/mL$