Scientific Investigation

Safety: 1.What is a fume hood used for? 2.What are 3 precautions you should take when handling chemicals? 3.What is an SDS? What is some of the information found on an SDS?

Label the safety equipment. Explain the use for each. 1.Exits5. Fire extinguisher 2.Shower6. Fire blanket 3.Goggles7. Fume hood 4.Eyewash8.

If you spill an acid or a base on yourself, you should: A.rinse with acetone or another suitable solvent or neutralizing solution. B.ask your teacher what to do C.immediately wash with soap and cool water and tell your teacher D.go immediately to the clinic E.do nothing unless you feel a burn or irritation

You or your neighbor's clothing catches fire, what should you do? A.drop to the floor and roll to extinguish the flames - if it's your lab mate who's clothing is on fire, help them to do the same B.run C.go to the safety shower

If something on your lab benches catches fire, what is the best response from the choices below? A. always run for the fire extinguisher if you see a flame B. if and only if it is possible to do so safely, cover the flames with a beaker or watchglass, remove solvents from the area, then get the fire extinguisher; if it is not possible to do this, leave the room and pull the fire alarm, and call 911 from a safe phone C. get the safety wash and aim the water at the flames D. the moment you see a hint of the flame, immediately leave the room and pull the fire

You get a chemical in your eye. What should you do? A. nothing B.rinse with water for a few minutes and tell your teacher or the lab coordinator C.immediately flush with water, continue washing for 15 minutes, tell your teacher, then go to the clinic if so advised D.go to the restroom and rinse with water because the water is better there

What is the correct procedure for diluting an acid solution? A.Pour the acid into the water. B.Pour the water into the acid. C.Pour both the acid and water into a clean beaker at the same time. D.This is too dangerous to do.

Name the equipment

Scientific Investigation 1.What is the independent variable? 2.What is the dependent variable? 3.What is the general trend in the data?

Measurements Always estimate between the smallest two divisions on and instrument. If a measurement is exactly on a line always add a final zero. Measurements must have units.

Significant Figures How many significant figures are in each of the following? not Start counting at the first nonzero number and count the rest!

Identify each of the following as measurements of length, area, volume, mass, density, time or temperature. Give the significant figures in each. a.5 ns_______ ________sig figs b.25.5 mg_______ _______ sig figs c. 540 km2_______ _______

Calculations with measurements Do the following problems and round to the correct # of significant figures: 3.45 cm cm = 0.089g – g = 7.8 m x m = 8760 g / 8900 mL = Answers for + & - get rounded to the least number of decimal places! Answers for x & / get rounded to the least number of significant figures.!

(c) 2006, Mark Rosengarten Rounding with addition and subtraction Answers are rounded to the least precise place.

(c) 2006, Mark Rosengarten Rounding with multiplication and division Answers are rounded to the fewest number of significant figures.

Carry out the following calculations and round your answers to the correct number of significant figures. A g g g = _______________________________ B.( m)(347.0 m) = _______________________________ C.[(10.3 s)( m)] / [(1.68 s)(36.43)] = _______________________________

An ancient gold coin is 2.2 cm in diameter and 3.0 mm thick. It is a cylinder for with volume of 1.14 cm 3. What is the mass of gold in grams if gold has a density of 19.3 g/cm 3 ?

(c) 2006, Mark Rosengarten Metric Conversions Determine how many powers of ten difference there are between the two units (no prefix = 10 0 ) and create a conversion factor. Multiply or divide the given by the conversion factor. How many kg are in 38.2 cg? (38.2 cg) /( cg/kg) = km How many mL in dL? (0.988 dg) X (100 mL/dL) = 98.8 mL

Scientific Notation Ex. 3.2 x m Only one number in front of the decimal Units go on the outside of the number Positive exponent = move decimal to right Negative exponent = move decimal to left It is easiest to do calculations using scientific notation with a scientific calculator!! You are responsible for making sure you have one for the SOL test. They are not provided!!!

Accuracy vs Precision

Percent Error [Actual – Experimental] x100% Actual