Unit 1: Measurements Homework Packet (75 points)

Transcription

1 Name: Period: By the end of Unit 1 you should be able to: Measurements Chapter 3 1. Convert between scientific notation and standard notation 2. Define and identify significant digits including being able to round and perform mathematical operations (add, subtract, multiply and divide) 3. Know and use the metric system including their prefixes and symbols 4. Use dimensional analysis to convert between units 5. Use measuring devices with precision and accuracy 6. Create and interpret graphs by calculating a line of best fit and using the line to extrapolate and interpolate data 7. Define and calculate density Scientific Notation: Convert the following numbers into scientific notation. (pg ) x x x Scientific Notation: Convert the following numbers into standard notation. (pg ) x x x x x x 10 3 Significant Digits: Identify the number of significant digits in the following problems. (pg ) Example: has 3 significant digits

2 Significant Digits: Round each number to three significant digits in the following problems. (pg ) Example: would round to Significant Digits: Perform the following calculations and answer with the correct significant digits. (pg ) Significant Digits: Perform the following calculations and answer with the correct significant digits. (pg ) 37. If you buy 4.50 pounds of oranges for $1.25 per pound, what is the final price? $ If Mr. Goldsmith runs 26.2 miles in 3.2 hours, how fast was he running in miles per hour? 39. If $170,900 was given to 14 people, how much would each receive? $12, A rectangular fence was to be constructed around a yard was a square footage of ft 2. If two sides are ft, how long must the other side be? ft 41. If you have 42 grams of sample, how much sample would you place in 3.0 beakers if you wanted each to have the same amount?

3 SI Units: Listed below are objects to measure. Provide the best SI unit from the list to the right to perform the measurement. (pg ) 42. Length of the room 43. Time to run 100 yards seconds 44. Electric current 45. Temperature of the room Celsius 46. Mass of carbon 47. Water in a beaker milliliters 48. Amount of atoms Metric Conversions: Perform the following conversions. Show ALL work, units, and significant digits. Place answers in blanks provided.(pg ) L to ml g to dg Meters Moles Seconds Milliliters Celsius Grams Ampere mm to 0.34 dm x 10-9 m to nm mg to kg sec to minutes hr to 1500 sec ul to L Accuracy and Precision: Answer the following questions. (pg ) 57. Define accuracy. The ability to get close to the correct answer. 58. Define precision. 59. Which measuring device has greater precision, 4000 ml beaker with 10 marks or 100 ml graduated cylinder with 50 marks? Why? Graduated Cylinder.greater precision 60. Three samples of the same compound were made. They were massed at 22.3 g, 22.3 g, and 22.5 g. After doing some calculations, it was determined that theoretically 28.3 g should have been made. Was the person doing the procedure accurate or precise? Why? 61. I need 22.5 ml of water. Should I use a 100 ml graduated cylinder, 100 ml beaker, or 100 ml flask to measure the liquid. Why?

4 100 ml graduated cylinder.greater precision Using the pictures below, determine to what place each measuring device can be read to 100% certainty and what the actual reading would be. Reading with 100% Certainty Actual Reading 62. Beaker 63. Cylinder 64. Ruler 1 ml 52.5 ml Line of Best Fit: Answer the following questions. Be sure to show all work, units, and significant digits. 65. For the following sets of data points, calculate the slope that would be produced. a. (2,5) and (4,10) Slope: 2.5 b. (3.4, 5.8) and (4.8, 12.6) Slope: c. (0.23, 0.45) and (19, 9.2) Slope: 0.47 d. (5.7, 3.4) and (0.98, 0.86) Slope: 66. For the equation y=15x+b, calculate the value for b if you have the following data points: a. (4.3, 5.2) b= b. (0.55, 2.4) b= c. (0.23, 9.8) b= 6.3

5 d. (43, 52) b= 67. Using the data points, (4,5) and (8,15), calculate the slope and y-intercept (b). Y= 2.5 x Use your equation from #67 to determine the following: a. x=6 y= b. x=15 y= 32.5 c. y=8 x= d. y=0.4 x= 6.1 Graphing: Using the graphing paper on the following page, plot the data points below. Use this graph to answer the questions # Place density on the y-axis. Density of Sugar Water at Various Percents of Glucose % of glucose Density (g/ml) Calculate the line of best fit. Draw it on the graph below and provide the equation in the space provided.

6 Equation for line of best fit: y= x +. Data Points chosen to calculate the line (, ) and (, ) 70. Using the line of best fit from #69, what would the density of the sample be if the % of the glucose was: Density a b c d If you needed a sample of sugar water with a density of g/ml, what percent of the glucose would be required?

7 Density: Answer the following questions. Be sure to show your work, units, and use significant digits. Use the table provided for questions (pg ) Metal Density (g/cm 3 ) Aluminum 2.80 Copper 9.02 Gold 19.3 Brass 8.60 Steel A sample was massed at 23.5 grams. It takes up 8.21 cm 3. What metal makes up this sample? Aluminum 73. A steel sample had a volume of 1.5 cm 3. What is the mass of the sample? 74. A copper sample has a mass of 34.5 grams. What is the volume of the sample? 3.82 g/cm An unknown sample was given for analysis. It has a mass of 2.43 grams and takes up cm 3. What was the sample? 76. A golf ball has a density of 1.15 g/cm 3. Will it float on water? Will it float on saturated salt water (density = 1.20 g/cm 3 )? If it has a mass of g, what is its volume? Float on water: No Float on salt water: Yes Volume: 39.5 cm 3