1. Chemical Foundations

2.  Every quantitative observation or measurement consists of two parts, the number and the unit.  The fundamental SI base units include ◦ Length-meter ◦ Mass-kilogram/gram ◦ Time-second ◦ Temperature-Kelvin ◦ Amount of a substance-mole ◦ Electrical current-ampere

3.  Mega  Kilo  Deci  Centi  Milli  Micro  Nano  M…10^6  k…10^3  d…10^-1  c…10^-2  m…10^-3  μ…10^-6  n…10^-9

4.  The combination of two or more SI base units ◦ The most common that we encounter will be volume.  To find the volume of a cube, we calculate the product of its length, width and height.  Sample: Derive the liter from a cubic meter

5.  Every measurement that is made in the lab has some degree of uncertainty.  Example: Read the volume of liquid in the graduated cylinder…compare student results to emphasize where uncertainty is.  Certain digits vs. Uncertain digits ◦ Report all measurements by recording all certain digits and the first uncertain digit. ◦ These numbers are called the significant figures of the measurement.

6.  Accuracy refers to the agreement of a particular value with the true value.  Precision refers to the degree of agreement among several measurements of the same quantity.  Error ◦ Random error means that a measurement has equal probability of being too high or too low and occurs when estimating the value of the last digit in a measurement. ◦ Systematic error occurs in the same direction all of the time and is indicative of a problem with the procedure or equipment.

7.  Rules for counting significant figures ◦ Nonzero integers are always significant ◦ Zeros  Leading zeros or zeroes to the left are never significant, they are just placeholders  Captive zeros are always significant  Trailing zeros or zeros to the right are only significant if there is a decimal point. ◦ Exact numbers or numbers not obtained through measurement have an infinite number of significant figures.

8.  Multiplication and Division ◦ The number of significant figures in the result is the same as the number of significant figures in the least precise measurement used in the calculation.  Addition and Subtraction ◦ The number of decimal places in the result is the same as the number of decimal places in the least precise measurement used in the calculation.

9.  All significant figures and all rounding are calculated as the last step in every problem.  Examples: ◦ 4.56 x 1.4 = ◦ 21- 13.8 = ◦ (2.34 + 5.6)/(2.3 x 18)=

10.  Systematic approach to convert a given result into a different system of units. ◦ To do this we multiply the starting quantity by some form of 1 to change its units. ◦ Often this must be done multiple times to reach the desired unit.  You will need to memorize common conversion factors such as those in table 1.4 on page 16.

11.  7 inches = __________cm  10km = _________miles  8.67kg = _________ng  5.6x10 10 μm=__________Mm

12.  Three systems for measuring temperature are widely used: Celsius, Kelvin and Fahrenheit Scales.  Conversions ◦ Conversions between the Celsius and the Kelvin scale are simple because the size of the degree is the same, they just having different starting points.  Add or subtract 273. ◦ Conversions between Celsius and Fahrenheit are more difficult because the size of the degree is no the same.  T F = T C x (9/5) + 32  T C = (T F - 32) x (5/9)

13.  Calculated value measuring the amount of matter in a given volume of the substance.  Density is often used to identify a substance since every substance has its own density.  Determined by taking the mass of the substance and dividing by its volume.  You will no longer be asked to simply solve for the density but rather expected to be able to use density in other more difficult calculations.

14.  Matter is defined as anything that has mass and takes up space. ◦ Matter can be broken into two broad categories: Mixtures and Pure Substances  Mixtures can be broken down into homo or heterogeneous.  Homo  Hetero  Separation Techniques  Pure substances can be broken into compounds or elements  Elements  Compounds