Question

1. you are conducting an experiment and find the volume of a substance to be 9.85 ml. if the known volume of the substance is 10.25 ml, find the percentage error in your measurement. a. -3.90% b. -4.06% c. 3.90% d. 4.06% 14. a factor in an experiment that is kept the same amongst all groups in an experiment is the a. control group b. independent variable c. constant d. dependent variable 15. how many significant figures are in the speed of light, 3.0 x 10^8 m/s? a. 0 b. 2 c. 5 d. 8 16. which of the following is not a sign that a chemical reaction may have occurred? a. sudden color change from clear to yellow b. changing state from liquid to gas c. the formation of a precipitate d. giving off heat 17. four different liquids (syrup, water, motor oil, and alcohol) are spilled at the same time on an inclined plane. the data table to the right shows the time it took each to reach the bottom of the plane. based on the data table, which liquid is most likely the most viscous? a. syrup b. water c. motor oil d. alcohol liquid time (s) syrup 14.2 water 3.7 motor oil 10.5 alcohol 5.9 18. what is purposefully being manipulated and changed in an experiment is the a. control group b. independent variable c. constant d. dependent variable 19. calcium chloride has a density of 2.50 g/cm^3. if you have 218 g of it, what volume do you have? a. 87.2 cm^3 b. 545 cm^3 c. 87.2 g d. 545 g

Explanation:

13.

Step1: Recall percentage - error formula

The formula for percentage error is $\text{Percentage Error}=\frac{\vert\text{Measured Value}-\text{True Value}\vert}{\text{True Value}}\times100\%$. The measured value is $9.85$ mL and the true value is $10.25$ mL.

Step2: Calculate the difference

$\vert9.85 - 10.25\vert=\vert- 0.4\vert = 0.4$ mL.

Step3: Calculate the percentage error

$\text{Percentage Error}=\frac{0.4}{10.25}\times100\%=\frac{40}{10.25}\% \approx 3.90\%$.

In an experiment, a factor that is kept the same among all groups is called a constant. A control group is a group that is not exposed to the experimental treatment. An independent variable is what is manipulated, and a dependent variable is what is measured.

In scientific notation, the significant figures are the digits in the coefficient. For $3.0\times10^{8}$ m/s, the coefficient is $3.0$, which has 2 significant figures.

Answer:

C. 3.90%

14.