Math in Chemistry Unit 1B

 What is it?  Anything that has ______ and ____________  What is volume?  _______________________________________  What tools are used to measure volume?  For liquids – ____________________________  For solids – ______________________________ Matter

 What is mass?  ___________________________________  Measured in ___________, usually with a balance  Related to, but not the same as ________________  What is weight?  _________________________________________

 Most properties of matter are best described in quantitative terms  A quantitative measurement has ___________________  There are __________ associated with quantitative measurements Units of measurement

 What is the SI system?  A subset of the metric system adopted in 1960 as the standard system of measurement units  The most common units used in chemistry:  _______length__  _______mass__  _______time__  _______temperature__  _______amount of substance__ Systeme Internationale (SI)

 Based on ________  Prefixes identify the factor of 10  Kilo = ______ (k)  Hecta =______ (h)  Deka = ______ (dk)  Deci = ______ (d)  Centi = ______ (c)  Milli = ______ (m) SI Prefixes

This pneumonic device should help you remember the basic metric prefixes: __________________________ ________________________ ________________________ (kilo, hecta, deka, unit, deci, centi, milli) Remembering Prefixes

Metric conversions

 What is scientific notation?  _______________________________________________ _______________________________________________  M x 10 x  When moving the decimal left, the exponent is ____  When moving the decimal right, the exponent is ____ Scientific notation

 10 0 = ___  10 1 = ___  10 2 = ___  10 3 = ___  + exp. = __________  Large #’s > 1 o = ___ = ___ o = ___ = ___ o = ___ = ___ o - exp. = ___________ o Very small #’s < 1

1.Before +/-, make sure all #’s have the same exponent: 1.Ex. 9.9 x 10 2  x x 10 4  x x M 1 x 10 x +/- M 2 x 10 x M 1 +/- M 2 x 10 x Using scientific Notation

2.Multiplication: 1.Add exponents after multiplying M values 2.M 1 x 10 x x M 2 x 10 y 1.__________________________________

Division: 1.Subtract exponents after dividing M values 2.M 1 x 10 x d M 2 x 10 y 1.________________________________________

1.Exact numbers 1.Counting 2.Results of definitions (1 hour = 60 minutes) 2.Measurements – are never exact. These are limited by the instrument used. 1.BR scale – nearest lb(2 lbs) 2.Food scale – nearest ounce(2.25 lbs) Significant Figures

Significant figures in measurements include _____________________________________________ _____________________________________________ Ex.6.35 m6 and 3 are certain, 5 is uncertain, so there are ___ significant figures. Scientists agree +/- 1 in last sig. fig.

1.ALL _________ digits are significant (1234 has ___ sig. figs.) 2.“_____________” (those zeroes before a non-zero digit) are ______ significant. They are used only to locate the decimal. ( has _____ sig. fig.) Rules for determining how many significant figures

3.“____________” (those zeroes between two non- zero digits) are _______ sig. (50005 has _ sig. figs.) 4.“_____________” that follow a non-zero digit and are not followed by a decimal are _____ significant. (50000 has __ sig. fig) 5.“______________” that follow a non-zero digit and ARE followed by a decimal ____ significant. ( has __ sig. figs.)

1.In addition and subtraction: 1.Round answer to the part of the equation with the fewest significant figures = ___________ Using Significant Figures

1.In multiplication and division: 1.Round your answer to the same # of significant figures as your factor having the least # of sig. figs. If a factor is an exact number, do not include it in your sig. figs. 1.If a factor is a conversion factor (1 hr = 60 min), do not include it in your sig. figs. 2 x 237 = 474 = _______ (w/ sig figs) If, however, 2 is an exact number, then your answer would be _______.

1.Precision – _________________________________ (a precise measurement should be measured +/- 1 digit each time) 2.Accuracy – __________________________________________ __________________________________________ (again, this should be +/- 1 digit) Why use significant figures?

 What is a conversion factor?  A mathematical expression that _______________________________________________ _______________________________________________  Based on statements of ________________________  Ex._________________________________  Can be written as: Conversion Factors

1.ALWAYS write both the ______________________ ( ex. ________, NOT ___) 2.Units act like _____________________in solving equations. a.Cannot ______ unlike units 1.3x + 4y = ___________ 2.3cm + 4 dm = __________ 3.3 cm + 40 cm = _________ Using conversion factors in Dimensional Analysis

3.CAN ___ units 1.a.X x Y = ____ 2.b.cm x cm = ________ 3.g x cm 2 /sec = _________ 4.CAN ___ and ______ units

1.Study the problem (highlight key info) 2.Write down all data with label and units 1.Ex. Mass = 3 g 1.(label) amt. unit 2.Write down what you are asked to find 1.V = ? L Problem-solving strategies

3.Find a __________ that connects the given data to the information you’re trying to find. 4.Use __________________________________________ __________________________________________ 5.Check your result (_________________________)

If a person drives 88 km/hr for 2 hours, how far will they have traveled? speed = _____time = __________ distance = ? Example 1

Convert the mass of a 180 lb person to appropriate metric units. Example 2

How many minutes are there in 2 weeks? 1.Realize that you will need more than 1 conversion factor to get from minutes to weeks. 2.What conversion factors do we know? 1.1 week = ___ days 2.1 day = ___ hours 3.1 hour = ___ minutes Example 3

 What is a derived unit?  A unit _________ from a combination of the seven base units:  Ex. _______ is derived by multiplying the length, width and height of an object.  1 cm 3 = ____ (where mL is our derived unit) Derived units