Flashcards for Unit 1

Anything that has mass & occupies space. Matter

Weight A measure of the gravitational pull on matter. You would weigh less on the moon!

Mass A measure of the quantity of matter. You would have the same mass on the moon.

Scientific Method A series of steps followed to solve problems, including collecting data, forming a hypothesis, testing the hypothesis, and stating conclusions.

Observation A fact you take in with your senses.

Hypothesis A testable statement

Conclusion An inference

Scientific Law Describes what happens. Often stated mathematically. Summarizes many (thousands of) observations.

Theory A model that tries to explain why nature behaves a certain way. May be modified.

How many fundamental units in the SI system? 7

Physical quantity that must be measured. It cannot be calculated. Fundamental or Base Unit

A unit defined as a combination of fundamental units. Derived Unit

Unit of Mass Unit of Time Unit of Length Unit of Temperature Unit of Amount of Substance Unit of Volume: derived unit (Space or capacity) Kilogram Second Meter Kelvin Mole Liter, milliliter, cubic centimeter

Liter Metric Unit of Volume 10 cm X 10 cm 10 cm Derived Unit

? cm 3 = 1 Liter 1000 cm 3 = 1 Liter Derived Unit

? milliliter = 1 Liter 1000 mL = 1 Liter Derived Unit

? milliliter = 1 cm 3 1 mL = 1 cm 3 Derived Unit

What is the mass of 1 liter of pure H 2 O? 1 kilogram Mass/Volume relationship

What is the volume of 1 kg of pure H 2 O? 1 liter Mass/Volume relationship

What is the mass of 1 cm 3 of pure H 2 O? 1 gram Mass/Volume relationship

What is the volume of 1 gram of pure H 2 O? 1 cm 3 or 1 mL Mass/Volume relationship

Freezing Point of water in the Kelvin scale. 273 K Physical Constant

Boiling Point of water in the Kelvin scale. 373 K Physical Constant

Freezing Point of water in the centigrade scale. 0 C0 C0 C0 C Physical Constant

Boiling Point of water in the centigrade scale. 100  C Physical Constant

Ice / water equilibrium Another name for freezing point.

Steam / water equilibrium Another name for boiling point.

? cm in 1 meter 100 cm = 1 meter Conversion Fact

? mm in 1 meter 1000 mm = 1 meter Conversion Fact

? m in 1 km 1000 m = 1 kilometer Conversion Fact

? mg in 1 g 1000 mg = 1 gram Conversion Fact

Density Mass / Volume

Density Describes how matter is packed into space.

Units of Density grams / cm 3 for solids grams / ml for liquids

Density D M V

Accuracy How close a measured value is to an accepted value.

Precision How close a series of measurements are to one another.

High Precision Low Scatter

Percent Error  Measured value – Accepted value  x 100% Table T, reference tables Accepted value

Temperature A measure of the average kinetic energy of the particles of a system.

 C to K Table T, reference tables K =  C + 273

Scientific Notation The number is written as a product of 2 numbers: - a number between 1 & 10 - a power of 10

2 X Negative exponent so the number is between 0 and 1: 0.002

5 X 10 2 Positive exponent so the number is greater than 1: 500

Convert 345 X to scientific notation X The 1st factor got smaller by a factor of 100. So the 2 nd factor must increase by a factor of 100.

Significant Figures All known digits plus 1 estimated digit. From the perspective of the person MAKING the measurement.

cm Interpreting someone else’s measurements. Decimal Present – Pacific side Start counting at 1 st nonzero # and count until the end of the number. 7 sig figs

g Decimal Present – Pacific side Start counting at 1 st nonzero # and count until the end of the number. 3 sig figs 123 Interpreting someone else’s measurements.

4855 g Decimal Absent – Atlantic side Start counting at 1 st nonzero # and count until the end of the number. 4 sig figs 1234

4000 mm Decimal Absent – Atlantic side Start counting at 1 st nonzero # and count until the end of the number. 1 sig fig 1

Rule for sig figs in Addition and Subtraction Answer has same number of decimal places as the addend with the least number of decimal places.

28.0 cm cm cm cm But what do you report? 77.2 cm is correct! Least # of decimal places !

Rule for sig figs in Multiplication & Division Answer has same number of significant figures as the factor with the least number of significant figures.

24 m X 3.26 m = m 2 But what do you report? 78 m 2 is correct! 2 sig figs 3 sig figs

An aluminum cube has a mass of 4.75 grams. The dimensions of the cube are 1.2 cm X 1.2 cm X 1.2 cm. What is the density of the cube? a) g/cm 3 b) 2.75 g/cm 3 “Volume” = cm 3 c) 2.7 g/cm 3 d) 0.36 cm 3 /g 3 sig figs 2 sf

Calculating density by water displacement. Final Volume = 46.0 mL Initial Volume = 40.0 mL Volume of rock = 6.0 mL Mass of rock = 54.0 g Density of rock = 9.0 g/mL 2 sig figs – determined by the digits in the difference not by the raw data!

A solution contains grams of NaCl dissolved in 1.0 Liter of H 2 O. What is the molarity expressed to the correct sig figs? Molar Mass of NaCl = 58.5 grams. Calculated from P.T g 1 mole = moles 58.5 grams 58.5 grams moles/1.0 Liter = 0.75 M 5 sig figs 2 sig fig

Data Table 2 columns plus title independent variable – controlled by scientist (column 1) dependent variable – measured variable (column 2)

Graph 2 axes plus title independent variable – controlled by scientist (column 1) – GOES on X-AXIS dependent variable – measured variable (column 2) – GOES on Y-AXIS

Linear Relationship X-axis Y-axis Y = mX + b

Direct Relationship X-axis Y-axis Y = mX

Inverse Relationship X-axis Y-axis XY = k where k is a constant

Graph of a Constant X-axis Y-axis