1. Chapter #3 Section Assessment #1 - 56
Created by DRB, 2011

2. 3.1 section assessment
9. How do measurements relate to experimental science?
Making correct measurements is fundamental to the experimental sciences.

3. 3.1 section assessment 10. How are accuracy and precision evaluated?
Accuracy is the measured value compared to the correct values. Precision is comparing more than one measurement.

4. 3.1 section assessment
11. Why must a given measurement always be reported to the correct number of significant figures?
The significant figures in a calculated answer often depend on the number of significant figures of the measurements used in the calculation.

5. 3.1 section assessment
12. How does the precision of a calculated answer compare to the precision of the measurements used to obtain it?
A calculated answer can not be more precise than the least precise measurement used in the calculation.

6. 3.1 section assessment
13. A technician experimentally determined the boiling point of octane to be 124.1C. The actual boiling point of octane is 125.7C. Calculate the error and the percent error.
error = -1.6C; percent error = 1.3%

7. 3.1 section assessment a. unlimited
14. Determine the number of significant figures in each of the following.
a. 11 soccer players
b meter
c. 10,800 meters
d cubic meters
a. unlimited
b. 5
c. 3
d.3

8. 3.1 section assessment
15. Solve the following and express each answer in scientific notation and to the correct number of significant figures.
a. (5.3 x 10^4) + (1.3 x 10^4)
b. (7.2 x 10^-4)/(1.8 x 10^3)
c. 10^4 x 10^-3 x 10^ 7
d. (9.12 x 10^-1) – (4.7 x 10^-2)
e. (5.4 x 10^4) x (3.5 x 10^ 9)
a. 6.6 x 10^ 4
b. 4.0 x 10^ -7
c. 10^7
d x 10^ -1
e. 1.9 x 10^ 14

9. 3.2 section assessment
18. Which five SI base units are commonly used in chemistry?
m, kg, K, s, mol

10. 3.2 section assessment
19. Which metric units are commonly used to measure length, volume, mass, temperature, and energy?
Length: cm, m, km;
volume: L, mL, cm^3;
mass: kg, g, mg;
temperature: C, K;
energy: J, cal.

11. 3.2 section assessment
20. Name the quantity measured by each of the seven SI base units and give the SI symbol of the unit.
length (m)
mass (kg)
temperature (K)
time (s)
amount of substance (mol)
luminous intensity (cd)
electric current (A)

12. 3.2 section assessment a. m; 10^-3 of the unit
21. What is the meaning and symbol of each prefix?
a. milli-
b. nano-
c. deci-
d. centi-
a. m; 10^-3 of the unit
b. n; 10^-9 of the unit
c. d; 10^-1 of the unit
d. c; 10^-2 of the unit

13. 3.2 section assessment
22. List the following units in order from largest to smallest: m^3, mL, cL, uL, L, dL.
m^3 L dL cL mL uL

14. 3.2 section assessment
23. What is the volume of a paperback book 21cm tall, 12cm wide, and 3.5cm thick?
8.8 x 10^2 cm^3

15. 3.2 section assessment
24. State the difference between mass and weight.
Mass is the measure of the amount of matter in an object. Weight is a measure of the force of gravity on an object.

16. 3.2 section assessment
25. State the relationship between degrees Celsius and Kelvins.
C = K - 273

17. 3.2 section assessment
26. Surgical instruments may be sterilized by heating at 170 C for 1.5hr. Convert 170 C to Kelvins.
443K

18. 3.2 section assessment
27. State the relationship between joules and calories.
1J = cal

19. 3.3 section assessment
38. What happens to the numerical value of a measurement that is multiplied by a conversion factor? What happens to the actual size of the quantity?
The numerical value( and the unit) changes; the actual size does not change.

20. 3.3 section assessment 39. Why is dimensional analysis useful?
Dimensional analysis provides an alternative approach to problem solving.

21. 3.3 section assessment
40. What types of problems can be solved using dimensional analysis?
Conversion problems

22. 3.3 section assessment
41. What conversion factor would you use to convert between these pairs of units?
a. minutes to hours
b. grams to milligrams
c. cubic decimeters to milliliters
a. 1hour / 60 min
b. 10^3 mg / 1 g
c. 10^3 mL / 1 dm^3

23. 3.3 section assessment a. 1.48 x 10^7 ug b. 3.72 x 10^-3 kg to grams
42. Make the following conversions. Express your answers in standard exponential form.
a g to micrograms
b x 10^-3 kg to grams
c. 66.3L to cubic centimeters
a x 10^7 ug
b g
c x 10^4 cm^3

24. 3.3 section assessment 43. An atom of gold has a mass of
3.271 x 10^-22g. How many atoms of gold are in 5.00 g of gold?
1.53 x 10^22 atoms of gold

25. 3.3 section assessment
44. Convert the following. Express your answers in scientific notation.
a. 7.5 x 10^4 to kilojoules
b. 3.9 x 10^5 mg to decigrams
c x 10^-4 dL to microliters
a. 7.5 x 10^1 kJ
b. 3.9 x 10^3 dg
c x 10^1 uL

26. 3.3 section assessment
45. Light travels at a speed of 3.00x10^10 cm/sec. What is the speed of light in kilometers/hour?
1.08 x 10^9 km/h

27. 3.4 section assessment 50. What determines the density of an object?
Density is an intensive property that depends only on the composition of a substance, not on the size of the sample.
density = mass/volume

28. 3.4 section assessment 51. How does density vary with temperature?
Density generally decreases when temperature increases.

29. 3.4 section assessment
52. A weather balloon is inflated to a volume of
2.2 x 10^3 L with 37.4g of helium. What is the density of helium in grams per liter?
1.7 x 10^-2 g/L

30. 3.4 section assessment
53. A 68-g bar of gold is cut into 3 equal pieces. How does the density of each piece compare to the density of the original gold bar?
All the densities are equal.

31. 3.4 section assessment
54. A plastic ball with a volume of 19.7 cm^3 has a mass of 15.8g. Would this ball sink or float in a container of gasoline?
It would sink because the density of the ball, g/cm^3, is greater than the density of the gasoline.

32. 3.4 section assessment
55. What is the volume, in cubic centimeters, of a sample of cough syrup that has a mass of 50.0 g? The density of cough syrup is g/cm^3.
52.6 cm^3

33. 3.4 section assessment
56. What is the mass, in kilograms, of 14.0 L of gasoline? (Assume that the density of gasoline is g/cm^3.)
9.52 kg