Question

1. when converting 2.5 kilometers to meters, which method demonstrates the correct use of dimensional analysis?

a. 2.5 km × \frac{1000m}{1km}=2500m
b. 2.5 km × \frac{1m}{1000km}=0.0025
c. 2.5 km × \frac{100m}{1km}=250m
d. 2.5km ÷ \frac{1000m}{1km}=0.0025m

1. which of the following is not a required component of a formal lab report?

a. materials and methods section
b. personal opinions about the experiment
c. data analysis and results
d. discussion of experimental errors

1. a student measures 425 milliliters of a solution. what is this volume expressed in liters?

a. 4.25 l
b. 0.425 l
c. 42.5 l
d. 0.0425 l

1. in a lab reports methodology section, which sequence best represents proper organization?

a. results, materials, procedure, safety precautions
b. materials, safety precautions, procedure, expected results
c. hypothesis, materials, results, conclusion
d. safety precautions, materials, procedure, data collection methods

Explanation:

Step1: Recall metric - conversion factor

We know that 1 km = 1000 m. To convert km to m, we multiply by the conversion factor $\frac{1000m}{1km}$. For 2.5 km, the correct conversion is $2.5km\times\frac{1000m}{1km}=2500m$. So the answer to question 1 is a.

Step2: Identify components of a lab - report

A formal lab - report typically includes materials and methods, data analysis and results, and discussion of experimental errors. Personal opinions are not a required component. So the answer to question 2 is b.

Step3: Recall volume - conversion factor

We know that 1 L = 1000 mL. To convert mL to L, we divide by 1000. For 425 mL, $425mL\times\frac{1L}{1000mL}=0.425L$. So the answer to question 3 is b.

Step4: Recall methodology - section organization

In a lab - report's methodology section, the proper sequence is safety precautions, materials, procedure, data collection methods. So the answer to question 4 is d.

Answer:

1. a. $2.5 km\times\frac{1000m}{1km}=2500m$
2. b. Personal opinions about the experiment
3. b. 0.425 L
4. d. Safety precautions, materials, procedure, data collection methods