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Measurement A quantity that has both a number and a unit

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Scientific Notation A way of writing either very large or very small numbers. A way of writing either very large or very small numbers. One number to the left of the decimal point multiplied by a power of 10. One number to the left of the decimal point multiplied by a power of 10.

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Accuracy A measure of how close a measurement comes to the true value. A measure of how close a measurement comes to the true value. To evaluate accuracy your measurement must be compared to the true measurement To evaluate accuracy your measurement must be compared to the true measurement

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Precision A measure of how close a series of measurements are to each other. A measure of how close a series of measurements are to each other. To evaluate precision two or more measurements must be compared to each other. To evaluate precision two or more measurements must be compared to each other.

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Determining Error Accepted value – the correct value based on reliable references Accepted value – the correct value based on reliable references Experimental value – the value measured in the lab Experimental value – the value measured in the lab

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Error = experimental value Error = experimental value - accepted value - accepted value % error = lerrorl x 100 accepted value accepted value

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Significant Figures (sig figs) in measurements always depend on the instrument being used for the measurement. in measurements always depend on the instrument being used for the measurement. include all digits that are known plus one digit that is estimated. include all digits that are known plus one digit that is estimated.

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All measured numbers are significant figures. All measured numbers are significant figures. All non-zero numbers are measured. All non-zero numbers are measured. Zeros that are acting as place holders are not measured. Zeros that are acting as place holders are not measured.

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Is the zero measured? Leading zeros are never measured. Leading zeros are never measured. Captured zeros are always measured. Captured zeros are always measured. Trailing zeros are only measured if there is a decimal in the number. Trailing zeros are only measured if there is a decimal in the number.

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Measurements must always be reported to the correct number of sig figs because calculated answers often depend on the number of sig figs in the values used in the calculations. Measurements must always be reported to the correct number of sig figs because calculated answers often depend on the number of sig figs in the values used in the calculations.

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Significant figures in calculations In general a calculated answer cannot be more precise than the least precise measurement from which it was calculated. In general a calculated answer cannot be more precise than the least precise measurement from which it was calculated.

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Sig figs in addition and subtraction Round your answer to the same number of decimal places as the measurement with the least number of decimal places. Round your answer to the same number of decimal places as the measurement with the least number of decimal places.

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Sig figs in multiplication and division Round your answer to the same number of significant figures as the measurement with the least number of sig figs. Round your answer to the same number of significant figures as the measurement with the least number of sig figs.

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How many sig figs? meters grams x10 -2 meters liters grams 6.98,000 meters

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Round to 3 sig figs meters x 10 8 grams meters centimeters millimeters grams

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Calculate and round correctly m m +8.6m = 2.(5.3 x 10 4 ) + (1.3 x 10 3 ) = 3.(9.12 x ) – (4.7 x ) = cm -17.3cm = g g g = m – 12.52m – 8.24m=

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Calculate and round correctly m x 0.34m = cm x 0.70m = m/ 8.4 = cm x 11.3cm x 5.2cm = m/ 12.5 = x 10 4 / 1.7 x =

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International System of Units (SI) kilogram(kg) measures mass kilogram(kg) measures mass meter(m) measures length meter(m) measures length kelvin(K) measures temperature kelvin(K) measures temperature second(s) measures time second(s) measures time Mole(mol) measures amount Mole(mol) measures amount

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Volume Is a derived unit. Is a derived unit. SI unit of volume is the amount of space occupied by a cube that is 1 m along each edge SI unit of volume is the amount of space occupied by a cube that is 1 m along each edge The liter is a common unit of volume = a cube 10cm on each edge. The liter is a common unit of volume = a cube 10cm on each edge.

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Temperature The SI unit is the kelvin. The Kelvin temperature scale is directly related to kinetic energy. So zero energy = 0K The SI unit is the kelvin. The Kelvin temperature scale is directly related to kinetic energy. So zero energy = 0K K = o C K = o C o C = K o C = K - 273

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Conversion Factors A ratio of equal measurements. A ratio of equal measurements. 1 meter = 100 centimeters 1 meter = 100 centimeters 1 m, 100 cm 100 cm 1 m 1 m, 100 cm 100 cm 1 m

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Dimensional Analysis A way to analyze and solve problems using the units, or dimensions, of the measurement. A way to analyze and solve problems using the units, or dimensions, of the measurement.

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How many minutes are in exactly one week. How many minutes are in exactly one week minutes minutes

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An experiment requires that each student use an 8.5-cm length of Mg ribbon. How many students can do the experiment with 570-cm of ribbon available? An experiment requires that each student use an 8.5-cm length of Mg ribbon. How many students can do the experiment with 570-cm of ribbon available? 67 students 67 students

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Convert km to meters km to meters 4.6 mg to grams 4.6 mg to grams g to centigrams g to centigrams 15 cm 3 to liters 15 cm 3 to liters 7.38 g to kg 7.38 g to kg 6.72 s to milliseconds 6.72 s to milliseconds

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The radius of the potassium atom is nm. Express this radius in centimeters. The radius of the potassium atom is nm. Express this radius in centimeters x cm 2.27 x cm

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Density Is the ratio of an objects mass to its volume. Is the ratio of an objects mass to its volume. It can also be thought of as an equality. It can also be thought of as an equality. Density of gold=19.3g/cm 3 Density of gold=19.3g/cm g Au = 1 cm 3 Au 19.3g Au = 1 cm 3 Au

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Gold has a density of 19.3 g/cm 3. What is this density in kilograms per cubic meter ? Gold has a density of 19.3 g/cm 3. What is this density in kilograms per cubic meter ? 1930 kg/m kg/m 3

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A student finds a shiny piece of metal she thinks is aluminum. She measures the mass to be 612 g and the volume to be 245 cm 3. Is the sample aluminum? A student finds a shiny piece of metal she thinks is aluminum. She measures the mass to be 612 g and the volume to be 245 cm 3. Is the sample aluminum? Why or why not? Why or why not?

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What is the volume of 4.62 g of mercury? What is the volume of 4.62 g of mercury? What is the mass of 2.00 L of corn oil? What is the mass of 2.00 L of corn oil? What is the volume of 1.25 kg of air? What is the volume of 1.25 kg of air?

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