Chapter 3 Ultimate Review! Mrs. DiGennaro Chem 1A

Quantitative vs. Qualitative Quantitative = QUANTITY = NUMBERS (It is 39 degrees Celsius) Qualitative = QUALITY = NO NUMBERS (it is hot) You try it: Describe your shoes qualitatively and quanitatively

Scientific Notation Move the decimal behind the first non-zero digit Count the number of ‘jumps’ Jump right? Negative exponent Jump left? Positive exponent You try it: 3,123,901.22 0.0005678

Accuracy/Precision/Error Accuracy: How close your values are to the ‘true value’ Precision: How close your measurements are to each other. Error: ‘How wrong were you?’ … This is the (absolute value of) difference between your value and the accepted value (difference means SUBTRACT) Percent Error: IErrorI/accepted value x 100 You try it! Elizabeth performed an experiment and found that water boiled at 98 degrees celsius. What is the percent error of her data? What could have caused this error?

Significant figures KNOW THE RULES! Every non-zero digit is significant= 1,234 has 4 significant figures Zeros between non-zero digits are significant = 1001 has 4 significant figures Leftmost zeros before a nonzero digit are NOT significant = 0.000012 has 2 significant figures Zeros at the end of a number AND to the right of a decimal point ARE significant 100.23 has 5 significant figures Zeros at the end with no decimal point are NOT significant = 1,000,000 has 1 significant figure When adding/subtracting, line up decimal point and round your answer to the least number of DECIMAL places in the problem = 2.14 + 2.1 = 4.2 (The answer has 1 decimal place because that is the lowest number of decimal places) When Multiplying/dividing, round your answer to the least number of significant figures

SI system of Measurement Length = meter Volume = cubic meter Mass = kilogram* Temperature = kelvin* Time = second *Why do you think the SI unit is kilogram and not gram? Kelvin and not celsius?

Convert!!! mega (M) 1,000,000 times larger than the unit kilo (k) 1,000 times larger than the unit deci (d) 1/10 the size of the unit cent (c) 1/100 the size of the unit milli (m) 1/1000 the size of the unit micro ( ) 1/1,000,000 the size of the unit

Density Density= relationship between and objects mass and volume Density = mass/volume You try it: What is the density of a copper penny that has a mass of 3.1 grams and a volume of 0.35 cubic centimeters? What is your unit?

Temperature Temperature shows us the heat transfer Feels cold to you? Heat going to that object Feels hot to you? Heat going from object to you Temperature scales Celsius = based on freezing point (0 degrees) and boiling point (100 degrees) of water Kelvin = based on ABSOLUTE ZERO K = Degrees Celsius + 273 Degrees Celsius = K – 273 You try it! At what temperature (kelvin) does water boil? At what temperature (kelvin) does water freeze?

What type of questions will you see? Conversion questions. For example, how many grams in 27.4 kilograms? Significant figures Count them, round to a specific significant figure, add/subtract/multiply/divide Write in scientific notation Is it accurate? Precise? What is the percent error? Be able to solve for the missing value in a density problem Temperature conversion: kelvin-Celsius and reverse