Welcome to Chemistry I

Chemistry I-4 th Block: 1/6/14 Due: Syllabus signed-place in tray Objectives: Discuss and Apply Lab Safety Rules Review Scientific Skills-graphing Homework: Review Lab Safety Rules-safety test tomorrow Graphing Assignment

Safe, Engaging, and Productive Classroom?

What is chemistry ?-4th Block

What is chemistry? Study of Matter -Identify and classify matter based on its composition/make-up. -Analyze the chemical and physical changes of matter.

Elements: Different Atoms

Classification of Matter

Elements: Different Atoms

Scientific Skills Objectives I can distinguish between the independent and dependent variable in an experiment. I can distinguish between quantitative and qualitative data. I can distinguish between accurate and precise results. I can plot and interpret experimental data. I can convert between measurements. I can establish a relationship between significant figures and accuracy of a measurement. When calculating with measurements, I can express and answer to the correct degree of accuracy. I can apply the density equation to problems.

Experimental Variables Independent variable -Variable “I” control; manipulated during the expt. -Graph on x-axis Dependent Variable -Variable that “depends” upon the independent variable. -Graph on y-axis

Hummingbird Graphing Assignment

Types of Experimental Results Qualitative Results: (quality) -results observed through your senses. -subjective results Quantitative Results:(quantity) -measurements/calculations from an experiment. -definitive results

Measurements and Conversions

Scientific Skills Review: Bell Ringer *Use data from data table on worksheet to answer questions: 1. What is the independent variable in this experiment? 2. What is the dependent variable in this experiment? 3. a. A qualitative observation from this experiment? b. A quantitative observation from this experiment?

Scientific Skills Review: Bell Ringer *Use data from data table on worksheet to answer questions: 1. What is the independent variable in this experiment? 2. What is the dependent variable in this experiment? 3. a. A qualitative observation from this experiment? b. A quantitative observation from this experiment?

Measurements and Conversions

Measurement Conversion Lab Purpose: To make accurate measurements and conversions. Must show work(your thinking!) for conversions to receive full credit.

Measurement Conversion Lab

Measurements and Conversions

Measurement Conversions

Bell Ringer: Scientific Skills 1.Make the correct unit conversions. a L = _____mL b.500 g = ____kg c.How many meters are in 22.5 in? d.How many ft are in 13.5 km? 2.Determine if the experimental masses is/are accurate, precise, or both? The actual value of the rock is 2.5 grams. Mass (g)Trial 1Trial 2Trial 3Trial 4 rock

Scientific Notation Way to abbreviate very large or small measurements. Move decimal place so value of measurement is between 1 and 10. If initial measurement is smaller than one, the exponent is negative. If initial measurement is larger than one, the exponent is positive.

Scientific Notation

Analyzing Quantitative Data Precision : Accuracy:

Analyzing Quantitative Data Precision : Accuracy:

Accuracy vs. Precision Accurate Results: -Compare experimental data with the actual value. -When experimental data is equal to the actual value. Precise Results: - Comparing experimental data from several trials or from different lab groups in a class. -When experimental data is similar to one another.

Exit Slip: Scientific Skills 1. Convert each measurement below to scientific notation. a.The Earth is 92,960,000 miles from the sun. b. The approximate diameter (length) of a carbon atom is cm. 2. How would you explain to a friend the difference between accuracy and precision? You can include a picture.

Bell Ringer: Scientific Skills 1. Convert each measurement to scientific notation. a.The Earth is 92,960,000 miles from the sun. b. The approximate diameter of a carbon atom is cm. 2. How would you explain to a friend the difference between accuracy and precision (you can include an illustration)?

Accuracy vs. Precision Accurate Results: -Compare experimental data with the actual value. -When experimental data is equal to the actual value. Precise Results: - Comparing experimental data from several trials or from different lab groups in a class. -When experimental data is similar to one another.

Chemistry I-4th Block: 1/13/15 Due: Scientific Skills worksheets(lab) Measurement Lab-complete today Objectives: I can convert between measurements. I can classify data as accurate and/or precise. I can apply scientific notation to measurements. I can identify significant figures in a measurement. (Significant Figures Lab)

Accurate Measurements Purpose: To practice taking correct measurements and apply appropriate conversions. Every measurement has some degree of uncertainty. Depends upon the instrument used. Determine the correct measurement for the length of paper for Ruler A and Ruler B:

Accurate Measurments Every measurement has some degree of uncertainty. Depends upon the instrument used. Determine the correct measurement for the length of paper for Ruler A and Ruler B:

Significant Figures Lab Purpose: Take accurate measurements. Identify and understand the importance of significant figures in a measurement.

Chemistry I-4th Block: 1/14/15 Due: Measurement Lab-place in tray Objectives: Scientific Skills Review Quiz (interpreting and graphing data) I can identify significant figures in a measurement. When performing calculations with data, I can express answers to the correct degree of accuracy. Homework: Significant Figures Lab-post qts. Significant Figures worksheet

Significant Figures Significant Figures: The numbers directly related to an object’s measurement. Place holders are NOT significant figures. Importance of significant figures? Determines the degree of accuracy for a measurement.

Significant Figures in Measurements 1.All non-zero numbers (1-9) are significant. Ex. 234 g = 3 significant figures (sig. figs) 2. Zeros in between nonzero numbers are significant. Ex. 2,034 g = 4 sig. figs. 3. Leading zeros (come before non-zero numbers) are NOT significant. Only serve as placeholders. Ex = 3 sig. figs 4. Trailing zeros (come after non-zero numbers) are significant IF there is a decimal point in the measurement. Ex g = 4 sig. figs. Ex. 2,340 g = 3 sig. figs.

Significant Figures in Measurements

Calculating with Measurements “Your only as good as your weakest link.” An answer from a calculation involving measurements, can only be as accurate (good) as the weakest measurement in the calculation.

Calculating with Significant Figures 1. Multiplying and Dividing: The # of sig. figs. in the answer must be equal to the # of sig. figs. in the weakest (least accurate) measurement. 2. Addition and Subtraction: The # of decimal places in the answer must be equal to the # of decimal places in the weakest measurement (least accurate).

Calculating with Significant Figures

Significant Figures Review How many significant figures are in each measurement? a.0.054g = 2 sig. figs. b g= 4 sig. figs. c.2,000g= 1 sig. fig. d g= 5 sig figs. Calculate each answer to the correct degree of accuracy. a.4.025g x 0.052g x 9.20g = 1.9 g 3 (2 sig. figs) b.3.2g g + 3g = 9 g 9g (no decimal places)

Density How do we calculate density? -Ratio of mass divided by volume of an object. -Heart!

Density Lab: Class’s Analysis Lab Group Expt. Density (g/mL) Lab GroupExpt. Density (g/mL)

Density Lab Post-Lab Qts.

Gallery Walk