Unit+1+-+Measurement

1) The distance between carbon atoms in ethylene is 134 picometers. Which of the following expresses that distance in meters? a. 1.34 x 10-12 m b. 1.34 x 10-13 m c. 1.34 x 10-7 m d. 1.34 x 10-10 m e. 1.34 x 10-6 m

2) A dose of medication was prescribed to be 35 microliters. Which of the following expresses that volume in centiliters? a. 3.5 x 105 cL b. 3.5 x 104 cL c. 3.5 cL d. 3.5 x 10-4 cL e. 3.5 x 10-3 cL

3) You prepare 1000. mL of tea and transfer it to a 1.00 quart pitcher for storage. Which of the following statements is true? a. The pitcher will be filled to 100% of its capacity with no tea spilled. b. The pitcher will be filled to 95% of its capacity. c. The pitcher will be filled to 50% of its capacity. d. The pitcher will be completely filled and a small amount of tea will overflow. e. The pitcher will be completed filled and most of the tea will overflow.

4) In an average year the American chemical industry produces more than 9.5 million metric tons of sodium carbonate. Over half of this is used in the manufacture of glass while another third is used in the production of detergents and other chemicals. How many pounds of sodium carbonate are produced annually? a. 2.1 x 1010 lb b. 4.3 x 109 lb c. 1.1 x 107 lb d. 2.2 x 106 lb e. 2.1 x 104 lb

5) The average distance between the Earth and the Moon is 240,000 miles. Express this distance in kilometers. a. 6.1 x 105 km b. 5.3 x 105 km c. 3.9 x 105 km d. 1.5 x 105 km e. 9.4 x 104 km

6) A large pizza has a diameter of 15 inches. Express this diameter in centimeters. a. 38 cm b. 24 cm c. 18 cm d. 9.3 cm e. 5.9 cm

7) The speed needed to escape the pull of Earth's gravity is 11.3 km/s. What is this speed in mi/h? a. 65,500 mi/hr b. 25,300 mi/hr c. 18,200 mi/hr d. 1,090 mi/hr e. 5.02 x 10-3 mi/hr

8) A flask has a mass of 78.23 g when empty and 593.63 g when filled with water. When the same flask is filled with concentrated sulfuric acid, H2SO4, its mass is 1026.57 g. What is the density of H2SO4? (Assume the density of water is 1.00 g/mL). a. 1.992 g/cm3 b. 1.840 g/cm3 c. 1.729 g/cm3 d. 1.598 g/cm3 e. 0.543 g/cm3

11) Which measurement is expressed to 4 significant figures? a. 0.00423 kg b. 24.049 cm c. 1300 ºC d. 82,306 m e. 62.40 g

12) Express 96,342 m using 2 significant figures. a. 9.60 x 104 m b. 9.6 x 104 m c. 9.60 x 10-4 m d. 9.6 x 10-4 m e. 96,000 m/

13) Bud M. Chemist must determine the density of a mineral sample. His four trials yield densities of 4.77 g/cm3, 4.67 g/cm3, 4.69 g/cm3, and 4.81 g/cm3. Independent studies found the correct density to be 4.75 g/cm3. Which of the following statements represents the best analysis of the data? a. Bud’s results have much greater accuracy than precision. b. Bud’s results have much greater precision than accuracy. c. Bud’s results have high accuracy and high precision. d. Bud’s results have low accuracy and low precision. e. Bud’s equipment is faulty.

14) When applying the scientific method, it is important to avoid any form of hypothesis. a. True b. False

15) The number 6.0448, rounded to 3 decimal places becomes 6.045. a. True b. False

16) The number 6.0448, rounded to 2 decimal places becomes 6.05. a. True b. False

NOTES MEASUREMENTS

Precision - taking several measurements the same way (precise ex: 1.25, 1.23, 1.21)

Accuracy - closeness of measurement to the accepted value for a quantity.

3 Rules for measurements; 1. Measurements can be accurate, but not precise 2. Be precise, but not accurate 3. May be accurate and precise

SIGNIFICANT FIGURES

Allow a precise answer

Depend upon 3 things; 1. Size of object being measured 2. Smallest division in measuring tool 3. Difficulty in measuring certain object

Rules for sig figs; 1. Nonzero digits are always significant figures (ex: 1,275.5 = 5 sf) 2. Zeros between nonzero #'s are significant figures (ex: 2003.4 = 5 sf) 3. Zeros at the beginning of a number are never significant figures (ex: 0.0045 = 2 sf) 4. Zeros after a # and after a decimal point are significant figures (ex: 0.7600 = 4 sf) 5, Zeros before an imaginary decimal and following a number aren't significant figures (ex: 5,000 = 1)

Adding/Subtracting with Significant Figures Involved - Look at the two numbers and identify which has the smallest amount of digits to the right of the decimal (ex: 2.445(4) + 2.3(2) -> (4.745)=4.7(2)

Multiplying/Dividing with Siginificant Figures Involved

- Look at the two numbers and identify which has the least amount of digits (ex: 2.565(4) x 8.30(3)=(21.2895) ->21.3(3)

SCIENTIFIC NOTATION

*When increasing in powers of ten move decimal left, when decreasing in powers of ten move decimal to right* Adding/Subtracting - 1. Make sure powers of 10 match, by adjusting decimal if necessary 2. Then solve by using numbers,not including powers of ten. EX: (7.88 x 10^4 cm - 1.55 x 10^3 cm) (7.88 x 10^4 cm - 0.155 x 10^4 cm) (7.725 x 10^4 cm)

Multiplying - Multiply numbers and add powers of ten together.

EX: (2.3 X 10^3 m)(5.7 x 10^4 m)                                                2.3 x 5.7=13.11 10^3 +10^4= 10^7                                                13.11 x 10^7 1.31 x 10^8 m

Dividing - Divide numbers and subtract powers of ten together.

Adjust new answer to correct scientific notation form.

DENSITY

density = mass/volume (d=m/v)

common units: grams/mL

* Volume of Cylinder - (Pi)r^2h

* Volume of a cube / rectangle - l x w x h

* Volume of a liquid - graduated cylinder

* Volume of a solid - use displacement (subtract difference in water levels) (accepted - actual)

COMMON CONVERSIONS 1 ft = 12 in                         1 microliters = 0.0001 centiliters 1 yd = 3 ft                         1 cm = .394 in                          1 cm = 0.01 meter 1 picometer = 1.0 x 10^-12 meters 1 microliter = 0.0001 centiliters 1 millilters = 0.001056 quarts 1 metric ton = 2204.62 lbs 1 mile = 1.609 km                         1 km/sec = 2236.93 mph

ANSWERS: 1. d                     2. e                      3. d                      4. a                       5. d                      6. a                      7. b                      8. a                       11. e                     12. d                     13. c                     14. false b                     15. a                     16. b