Review for TEST on Chapter 2

1. Review for TEST on Chapter 2 Measurement

2. Density • Density = mass/volume; units g/mL or g/cm3. • If mass is smaller, and volume is unchanged, predict what happens to density? • If mass is unchanged, and volume is decreased, predict what happens to density? • If mass is larger and volume increases, what happens to density? Density decreases Density increases can’t predict this.

3. Significant digits 0.00012000 0.0001204 1.2 x 103 10000 808 80890 5 sig. digs. 4 sig. digs. 2 sig. digs. 1 sig. dig. 3 sig. digs. 4 sig. digs.

4. Prefixes 1km = ___m 10 dm = ___ m 100 cm =___ m 1000 mm =___ m 1km = 1000m 10 dm = 1 m 100 cm =1 m 1000 mm =1 m __kL = 1000 L __ dL = 1 L __ cL = 1 L __ mL = 1 L 1kL = 1000 L 10 dL = 1 L 100 cL = 1 L 1000 mL = 1 L

5. Using conversion factors. • You have a 20.0 g of substance, how many kg do you have? • You have 8.9 kL, how many L do you have? • You have 860 g, how many mg do you have? 1kg 1000g 20.0 g = 0.0200 kg 1000 L 1 kL 8.9 kL = 8,900 L 1000 mg 1 g 860 g = 860,000 mg

6. time distance mass volume temperature seconds meters kg (we use g in Chem.) L (we use these and mL or cm3 1 cm3 = 1 mL) Kelvin (we measure in Celsius and convert to Kelvin) SI Units

7. Procedures • Always Read Labs before attempting. • Simplify instructions for easy use. • Pay attention to safety instuctions. • Record observations and Data as you follow the instructions to do the lab. • Write up your lab.

8. Density = mass/volume • Calcium chloride is used as a de-icer on roads in winter. It has a density of 2.50 g/cm3. What is the volume of 7.91 g of this substance? Density = Mass Volume mass = 7.91 g density = 2.50 g/cm3 Volume = ? Volume = Mass Density Volume = 7.91 g 2.50 g/cm3 Volume = 3.16 cm3 mass = volume x density

9. Accuracy Precision Significant Digit Measurement Mass Weight Volume procedure quantity balance graduated cylinder Vocabulary