Chapter 11 IB Chemistry Warm Ups Mrs. Hilliard

Chapter 11 Vocabulary 1. Scientific Notation- a way of expressing very large or small numbers to a power, must be a number between 1-9. Ex: 2.5 x 10 5 11. Negative correlation- one variable increases while the second variable decreases or vice versa. 2. Experimental error- the degree of uncertainty associated with every measurement. 12. Electromagnetic spectrum- the range of all possible frequencies of electromagnetic radiation, including gamma rays, x-rays, ultraviolet rays, radio and microwaves. 3. Random errors- uncontrolled variables that cannot be eliminated but can be reduced by repeated measurements. 13. Spectroscopy- the study of the interaction between matter and electromagnetic radiation. It originated through the study of visible light dispersed according to its wavelength, by a prism. 4. Absolute uncertainty- the margin of uncertainty associated with the result from a given measurement. Symbol is ∆A 14. Mass spectroscopy- an analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions. 5. Relative uncertainty- the ratio comparing the size of the absolute uncertainty to the size of the measured experimental result, A. formula is ∆A/A 6. Propagation of uncertainty- determining how the different uncertainties combine to give the resultant uncertainty. 15. H NMR- Proton Nuclear Mass Resonance Spectroscopy- is a research technique that exploits the magnetic properties of certain atomic nuclei. It determines the physical and chemical properties of atoms or the molecules in which they are contained. 7. Percentage error- expresses as a percentage the difference between an approximate or measured value and an exact or known value. Percentage error =accepted value- experimental value/ accepted value x 100% 16. Significant figures- (exponential notation) the number of digits reflecting the precision of a given measurement. Greater # of digits, greater certainty about numerical value of quantity. 8. Dependent variable- plotted on the y-axis 17. Degree of unsaturation (index of hydrogen deficiency IHD)- used to determine from a molecular formula the number of rings or multiple bonds in a molecule. 9. Independent variable- plotted on the x-axis 10. Positive correlation- where two variables increase or decrease in parallel to one another.

Sig Figs 1. List some qualitative data. 2. List some quantitative data. 3. Determine which targets are accurate, precise, neither, or both. 4. How many significant figures are in 0.0200g? 5. How many sig figs are in 2.000g? 6. How many sig figs are in 2.10004g? 7. The mass of a sample bottle and a piece of aluminum metal is 35.4200g. The mass of the empty sample bottle is 28.9200g. If the aluminum displaces 2.41 cm3 of water, calculate the density of aluminum, in g cm-3.

Sig Figs 1. List some qualitative data. Color, chemical reactivity, solubility, melting point 2. List some quantitative data. Temperature, mass, concentration 3. Determine which targets are accurate, precise, neither, or both. 4. How many significant figures are in 0.0200g? 3 5. How many sig figs are in 2.000g? 4 6. How many sig figs are in 2.10004g? 6 7. The mass of a sample bottle and a piece of aluminum metal is 35.4200g. The mass of the empty sample bottle is 28.9200g. If the aluminum displaces 2.41 cm3 of water, calculate the density of aluminum, in g cm-3. 35.4200g- 28.9200g= 6.5000g D=mass/volume D= 6.5000g/2.41cm3 D=2.70g/cm3 Remember sig figs with calculations

Scientific Notation Change 349000 into scientific notation. Convert 3.126 x 10-3 into standard notation. Convert 9.32 x 10 5 into standard notation.

Scientific Notation Change 349000 into scientific notation. Convert 3.126 x 10-3 into standard notation. Convert 9.32 x 10 5 into standard notation.

Density- Use page 73 in Chem book for densities What is the Density of a solution that has a mass of 22.2g and a volume of 14mL? Identify the solution. What is the Density of a solution that has a mass of 12g and a volume of 5.5mL? Identify the solution. What is the Density of a cube of wood if the mass is 43g and the volume is 1.25 mL? What type of wood is it?

Density- Use page 73 in Chem book for densities What is the Density of a solution that has a mass of 22.2g and a volume of 14mL? Identify the solution. 22.2g/14 mL=1.59g/mL = Sucrose (sugar solution) What is the Density of a solution that has a mass of 12g and a volume of 5.5mL? Identify the solution. 12g/5.5 mL = 2.18g/mL = Salt (Sodium Chloride Solution) What is the Density of a cube of wood if the mass is 43g and the volume is 1.25 mL? What type of wood is it? 43g/1.25mL= 34.4g/mL = Red Maple Wood

Data What is qualitative data? What is quantitative data? How can random errors be reduced? What is the difference in random errors and systematic errors? How do you record uncertainties?

Data What is qualitative data? All non-numerical information obtained from observations not from measurements. What is quantitative data? Information obtained from measurements, and always associated with random errors/uncertainties, determined by the apparatus, and by human limitations such as reaction times. How can random errors be reduced? Repeated trails and measurements What is the difference in random errors and systematic errors? Random errors occur because of uncontrolled variables in an experiment and cannot be eliminated. They can be reduced by repeated measurements. Random errors affect the precision of the results. Systematic errors are associated with a flaw in the actual experimental design or with the instrumentation used. Systematic errors imply that the measured quantity will always be greater or less than the true value. (instrumentation errors, experimental methodology errors, personal errors) How do you record uncertainties? As a range +/- to an appropriate precision. (ex: if mass could be between 3.55g and 3.57g is uncertainty of 0.01 +/-)

Measurements If a student calculates that the mass of a metal is 0.40 +/- 0.01g with a volume of 0.070 +/- 0.005 cm3. How should the density be recorded using this data? Which experimental procedure is most likely to lead to a large systematic error? Measuring the volume of a gas produced with a gas syringe Measuring the volume of a solution using a volumetric pipette Determining the concentration of a base by titration with a burette Determining the enthalpy change in neutralization in a flask A pipette reading is recorded as 43.30 +/- 0.05cm3. Which of the following could be the actual value? 43.39 cm3 43.28 cm3 43.33 cm3 A and C A and B A, B, and C B and C

Measurements If a student calculates that the mass of a metal is 0.40 +/- 0.01g with a volume of 0.070 +/- 0.005 cm3. How should the density be recorded using this data? D=M/V .40/.070=5.7 .01/.40=.03x100=3 .005/.070=.07x100=7 3+7=10/100x5.7=.6 5.7+/-0.6 Which experimental procedure is most likely to lead to a large systematic error? Measuring the volume of a gas produced with a gas syringe Measuring the volume of a solution using a volumetric pipette Determining the concentration of a base by titration with a burette Determining the enthalpy change in neutralization in a flask A pipette reading is recorded as 43.30 +/- 0.05cm3. Which of the following could be the actual value? 43.39 cm3 43.28 cm3 43.33 cm3 A and C A and B A, B, and C B and C

Errors A piece of copper with a mass of 21.023g was found to have a volume of 2.36cm3. A student carried out the following calculation to determine the density. Density (g cm-3)= 21.023/2.36 What is the best value the student could report for the density of copper? What is likely to be reduced when an experiment is repeated a number of times? What is the best method to decrease the random uncertainty of a measurement in an acid-base titration?

Errors A piece of copper with a mass of 21.023g was found to have a volume of 2.36cm3. A student carried out the following calculation to determine the density. Density (g cm-3)= 21.023/2.36 What is the best value the student could report for the density of copper? 8.91 (least total # of sig. figs when multiplying or dividing) What is likely to be reduced when an experiment is repeated a number of times? Random errors What is the best method to decrease the random uncertainty of a measurement in an acid-base titration? Repeat the titration

EMS- Electromagnetic Spectrum List the types of electromagnetic radiation in order of decreasing wavelength (longest first), include colors of visible light. What is the difference between a line spectrum and a continuous spectrum? The thinning of the ozone allows for more UV-B radiation to reach Earth’s surface, use the data table to explain why UV-A radiation is not as dangerous. Type of Radiation Wavelength (nm) UV-A 320-380 UV-B 290-320

EMS- Electromagnetic Spectrum List the types of electromagnetic radiation in order of decreasing wavelength (longest first), include colors of visible light. Radio waves, microwaves, Infrared waves, Visible light (red, orange, yellow, green, blue, Indigo, violet (ROYGBIV)), Ultraviolet (UV), X rays, gamma rays ( rays) What is the difference between a line spectrum and a continuous spectrum? Line spectrum is discrete lines, usually characteristic of excited atoms or molecules that makes up the electromagnetic spectrum consisting. Continuous spectrum apparently having all wavelengths over a comparatively wide range, usually characteristic of solids and other substances at high temperatures and pressures. The thinning of the ozone allows for more UV-B radiation to reach Earth’s surface, use the data table to explain why UV-A radiation is not as dangerous. The wavelength is longer for UV-A radiation so it is less dangerous to our cells. As wavelength decreases, the radiation becomes more dangerous. Type of Radiation Wavelength (nm) UV-A 320-380 UV-B 290-320