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Name Class Date, Accuracy Precision and Error Accuracy precision and error help determine the. reliability of measurements, The accuracy of a measurement is determined by how close the measured value is to the. actual value, The precision of a measurement is determined by how close repeated measurements are. to one another, Error is the difference between the measured value and the accepted value. Significant Figures Significant figures include all known digits plus one estimated digit. The number of significant figures reflects the precision of reported data. In calculations the number of significant figures in the least precise measurement is the. number of significant figures in the answer,Significant Figures.

Sample number 0 024050 5 significant figures, Not significant leftmost zeros in front of nonzero digits 0 024050. Significant a nonzero digit 0 024050,zeros between two nonzero digits 0 024050. zeros at the end of a number to the right of the decimal point. After reading Lesson 3 1 answer the following questions. Scientific Notation, 1 Why are numbers used in chemistry often expressed in scientific notation. Numbers used in chemical calculations are often very large or very small Writing. out all the zeros in such numbers can be very cumbersome Scientific notation makes. it easier to work with these numbers, 2 Circle the letter of each sentence that is true about numbers expressed in scientific notation. a A number expressed in scientific notation is written as the product of a coefficient. and 10 raised to a power,b The power of 10 is called the exponent.

c The coefficient is always a number greater than or equal to one and less than ten. d For numbers less than one the exponent is positive. Lesson 3 1 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, 3 Circle the letter of the answer in which 503 000 000 is written correctly in scientific. a 5 03 10 7,c 5 03 108,d 503 million,Accuracy Precision and Error. 4 Is the following sentence true or false To decide whether a measurement has. good precision or poor precision the measurement must be made more than once. Label each of the three following sentences that describes accuracy with an A Label each. sentence that describes precision with a P, P 5 Four of five repetitions of a measurement were numerically identical and the. fifth varied from the others in value by less than 1. P 6 Eight measurements were spread over a wide range. A 7 A single measurement is within 1 of the correct value. 8 On a dartboard darts that are closest to the bull s eye have been thrown with the. greatest accuracy On the second target draw three darts to represent three tosses. of lower precision but higher accuracy than the darts on the first target. First target Second target, 9 What is the meaning of accepted value with respect to an experimental measurement. The accepted value is the correct value based on reliable references. 10 Complete the following sentence For an experimental measurement the experimental. value minus the accepted value is called the error. 11 Is the following sentence true or false The value of an error must be positive. 12 Relative error is also called percent error, Lesson 3 1 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved.

Name Class Date, 13 The accepted value of a length measurement is 200 cm and the experimental value is. 198 cm Circle the letter of the value that shows the percent error of this measurement. Significant Figures, 14 If a thermometer is calibrated to the nearest degree to what part of a degree can you. estimate the temperature it measures one tenth of a degree. 15 Circle the letter of the correct digit In the measurement 43 52 cm which digit is the. most uncertain, 16 Circle the letter of the correct number of significant figures in the measurement 6 80 m. 17 List two situations in which measurements have an unlimited number of significant. a when the measurement involves counting, b when the measurement involves exactly defined quantities. 18 Circle the letter of each sentence that is true about significant figures. a Every nonzero digit in a reported measurement is assumed to be significant. b Zeros appearing between nonzero digits are never significant. c Leftmost zeros acting as placeholders in front of nonzero digits in numbers less than. one are not significant, d All rightmost zeros to the right of the decimal point are always significant.

e Zeros to the left of the decimal point that act as placeholders for the first nonzero digit. to the left of the decimal point are not significant. Lesson 3 1 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, 19 Is the following sentence true or false An answer is as precise as the most precise. measurement from which it was calculated false,Round the following measurements as indicated. 20 Round 65 145 meters to 4 significant figures 65 15 meters. 21 Round 100 1 C to 1 significant figure 100 C,22 Round 155 cm to two significant figures 160 cm. 23 Round 0 000718 kilograms to two significant figures 0 00072 kilograms. 24 Round 65 145 meters to three significant figures 65 1 meters. For students using the Foundation edition, 3 2 Units of Measurement assign problems 1 4 7 26 29 31 36. Essential Understanding Measurements are fundamental to the experimental sciences. Lesson Summary, Using SI Units Scientists use an internationally recognized system of units to.

communicate their findings,The SI units are based on multiples of 10. There are seven SI base units second meter kilogram Kelvin mole ampere and. Prefixes are added to the SI units because they extend the range of possible. measurements, Temperature Scales Temperature is a quantitative measure of the average kinetic energy. of particles in an object, Scientists most commonly use the Celsius and Kelvin scales. The zero point on the Kelvin scale is called absolute zero. Kelvin Celsius Conversion Equation is K C 273, One degree on the Celsius scale is the same as one kelvin on the Kelvin scale. Density Density is a ratio that compares the amount of mass per unit volume. The formula for density is density, Density depends on the kind of material but not on the size of the sample.

The density of a substance changes with temperature. Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date,BUILD Math Skills, Converting Among Temperatures The Fahrenheit scale is. based on the melting point of ice 32 degrees above 0 and the. boiling point of water 212 degrees above 0 However since. most of the rest of the world uses degrees Celsius it is important. to be able to convert from units of degrees Fahrenheit to. degrees Celsius, The SI base unit for temperature is Kelvin or K A temperature. of 0 K refers to the lowest possible temperature that can be reached. To convert degrees Celsius into kelvins,add 273 to the C. To convert kelvins into degrees Celsius,subtract 273 from the K. Sample Problem Mercury melts at 39 C What temperature is that in K. Add 273 to the C 39 C 273 234K,To convert Celsius temperatures into Fahrenheit.

multiply the Celsius temperature by 9,divide the answer by 5. Sample Problem Convert 40 C to F,Multiply the Celsius temperature. 40 x 9 360 Hint You can also use,the equation,Divide the answer by 5 360 5 72. Add 32 72 32 104 F, Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date,To convert Fahrenheit temperatures into Celsius.

subtract 32 from the Fahrenheit temperature,multiply the answer by 5. divide that answer by 9,Sample Problem Convert 77 F to C. Subtract 32 from the Fahrenheit,temperature,77 32 45 Hint You can also use. the equation,Multiply the answer by 5 45 x 5 225,Divide that answer by 9 225 9 25 C. Now it s your turn to practice converting temperatures. 1 Fill in the table below with the correct degrees. Common Temperatures,Fahrenheit F Celsius C Kelvin K.

Water boils 212 100 373,Human body 98 6 37 310,Average room 68 20 293. Water freezes 32 0 273, After reading Lesson 3 2 answer the following questions. Using SI Units, 2 Complete the table showing selected SI base units of measurement. Units of Measurement,Quantity SI Base Unit Symbol,Length meter m. Mass kilogram kg,Temperature kelvin K,Time second s.

Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, 3 All metric units of length are based on multiples of 10. 4 The International System of Units SI is a revised version of the metric system. 5 Explain what is meant by a derived unit, Derived units are combinations of base units All SI units are base units or are. derived from base units,6 Give at least one example of a derived unit. Students responses will vary Possible responses are units of volume density. 7 Complete the following table showing some metric units of length Remember that the. meter is the SI base unit for length,Metric Units of Length. Unit Symbol Factor Multiplying Base Unit,Kilometer km 1000.

Centimeter cm 10 2,Millimeter mm 10 3,Nanometer nm 10 9. Match each metric unit with the best estimate of its length or distance. b 8 Height of a stove top above the floor a 1 km,d 9 Thickness of about 10 sheets of paper b 1 m. a 10 Distance along a road spanning about c 1 cm,10 telephone poles. c 11 Width of a key on a computer keyboard, 12 The space occupied by any sample of matter is called its volume. 13 Circle the letter of each sentence that is true about units of volume. a The SI unit for volume is derived from the meter the SI unit for length. b The liter L is a unit of volume,c The liter is an SI unit.

d There are 1000 cm3 in 1 L and there are also 1000 mL in 1 L so 1 cm3 is equal to. Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, Match each of the three descriptions of a volume to the appropriate metric unit of volume. Example Unit of Volume,b 14 Interior of an oven a 1 L. a 15 A box of cookies b 1 m3,c 16 One quarter teaspoon c 1 mL. 17 A volume of 1 L is also equal to, 18 The volume of any solid liquid or gas will change with temperature. 19 A kilogram was originally defined as the mass of 1 L of liquid water at 4 C. 20 Circle the letter of the unit of mass commonly used in chemistry that equals 1 1000. b milligram,c milliliter, Match each unit of mass with the object whose mass would be closest to that unit.

Mass Unit of Mass,c 21 A few grains of sand a 1 kg. a 22 A liter bottle of soda b 1 g,b 23 Five aspirin tablets c 1 mg. 24 Is the following sentence true or false The mass of an object changes with location. 25 When brought to the surface of the moon will a mass have more or less weight than it. did on the surface of Earth or will it be the same weight Explain. Its weight will be less because weight is a measure of gravitational force and the. force of gravity on the moon is one sixth what it is on Earth. Temperature Scales, 26 Draw an arrow below the diagram showing the direction of heat transfer between two. lower higher,temperature temperature, Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, 27 What properties explain the behavior of liquid filled thermometers.

Almost all liquids expand in volume with an increase in temperature This expansion. forces the liquid higher in the thermometer tube as the temperature rises As the. temperature falls the liquid contracts and its level in the tube drops. 28 What are the two reference temperatures on the Celsius scale. The freezing point of water is 0 C and the boiling point of water is 100 C. 29 What is the zero point 0 K on the Kelvin scale called absolute zero. 30 A change of temperature equal to one kelvin is equal to a change of temperature of. how many degrees Celsius one, 31 Complete the diagram to show the reference temperatures in the Celsius and. Kelvin scales,Freezing point Boiling point,of water of water. 273 15 K 373 15 K,Kelvin divisions, 32 Is the mass of one pound of lead greater than less than or equal to the mass of one. pound of feathers equal to, 33 Which material has a greater density lead or feathers lead. 34 How is density defined, Density is the ratio of the mass of an object to its volume.

35 The mass of a sample is measured in grams and its volume is measured in cubic. centimeters In what units would its density be reported. grams per cubic centimeter g cm3, Lesson 3 2 Reading and Study Workbook Copyright Pearson Education Inc or its affiliates All Rights Reserved. Name Class Date, 36 Look at Table 3 6 Circle the letter of the material that will sink in liquid water at 4 C. a aluminum c ice,b corn oil d gasoline, 37 The density of a substance generally decreases as its temperature increases Are there any. exceptions to this statement Explain, Yes Over a small range of temperatures near the freezing point the density of water. after reading Lesson 3 1 answer the following questions Scientific notation 1 Why are numbers used in chemistry often expressed in scientific notation 2 Circle the letter of each sentence that is true about numbers expressed in scientific notation a A number expressed in scientific notation is written as the product of a coefficient

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