Temperature Conversions and Density Calculations

Temperature Scales FahrenheitFahrenheit CelsiusCelsius KelvinKelvin Anders Celsius Lord Kelvin (William Thomson)

Temperature Scales Boiling point of water Freezing point of water Celsius 100 ˚C 0 ˚C 100˚C Kelvin 373 K 273 K 100 K Fahrenheit 32 ˚F 212 ˚F 180˚F

Temperature Conversions: An Approach to Problem Solving Temperature Scales: Fahrenheit scale, o F; Celsius scale, o C; Kelvin scale, K Temperature Conversion Formulas Celsius to Kelvin: K = o C Celsius to Fahrenheit: o F = 1.80( o C) + 32 Fahrenheit to Celsius :

Calculations Using Temperature If body temp is 37 ˚C, what is the temperature in kelvin?If body temp is 37 ˚C, what is the temperature in kelvin? If nitrogen is liquid nitrogen at -196˚C, what is the temperature in kelvin?If nitrogen is liquid nitrogen at -196˚C, what is the temperature in kelvin? If body temp is 37 ˚C, what is the temperature in kelvin?If body temp is 37 ˚C, what is the temperature in kelvin? If nitrogen is liquid nitrogen at -196˚C, what is the temperature in kelvin?If nitrogen is liquid nitrogen at -196˚C, what is the temperature in kelvin?

Temperature Conversions Practice A person with hypothermia has a body temperature of 29.1°C. What is the body temperature in °F? Celsius to Fahrenheit: o F = 1.80( o C) + 32 °F = 9/5 (29.1°C) + 32 = = = 84.4°F

Learning Check The normal temperature of a chickadee is 105.8°F. What is that temperature in °C? The normal temperature of a chickadee is 105.8°F. What is that temperature in °C? 1) 73.8 °C 2) 58.8 °C 3) 41.0 °C

Learning Check Pizza is baked at 455°F. What is that in °C? 1) 437 °C 2) 235°C 3) 221°C

DENSITY - an important and useful physical property Mercury 13.6 g/cm g/cm 3 Aluminum 2.7 g/cm 3 Platinum

DENSITYDENSITY Density is an INTENSIVE property of matter.Density is an INTENSIVE property of matter. –does NOT depend on quantity of matter. –temperature Contrast with EXTENSIVEContrast with EXTENSIVE –depends on quantity of matter. –mass and volume. Styrofoam Brick

PROBLEM: Mercury (Hg) has a density of 13.6 g/cm 3. What is the mass of 95 mL of Hg in grams? In pounds?

Strategy 1.Use density to calc. mass (g) from volume. 2.Convert mass (g) to mass (lb) Need to know conversion factor = 454 g / 1 lb PROBLEM: Mercury (Hg) has a density of 13.6 g/cm 3. What is the mass of 95 mL of Hg? First, note that 1 cm 3 = 1 mL

1.Convert volume to mass PROBLEM: Mercury (Hg) has a density of 13.6 g/cm 3. What is the mass of 95 mL of Hg? 2.Convert mass (g) to mass (lb)

Learning Check Osmium is a very dense metal. What is its density in g/cm 3 if g of the metal occupies a volume of 2.22cm 3 ? 1) 2.25 g/cm 3 2)22.5 g/cm 3 3)111 g/cm 3

Solution 2) Placing the mass and volume of the osmium metal into the density setup, we obtain D = mass = g = volume2.22 cm 3 volume2.22 cm 3 = g/cm 3 = 22.5 g/cm 3 = g/cm 3 = 22.5 g/cm 3

Volume Displacement A solid displaces a matching volume of water when the solid is placed in water. 33 mL 25 mL

Learning Check What is the density (g/cm 3 ) of 48 g of a metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 mL? 1) 0.20 g/ cm 3 2) 6.0 g/m 3 3) 252 g/cm 3 33 mL 25 mL 2) 6.0 g/m 3 2) 6.0 g/m 3

Learning Check Which diagram represents the liquid layers in the cylinder? (K) Karo syrup (1.4 g/mL), (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL) 1) 2) 3) K K W W W V V V K 1)

Learning Check The density of octane, a component of gasoline, is g/mL. What is the mass, in kg, of 875 mL of octane? 1) kg 2) 614 kg 3) 1.25 kg 1) kg

Learning Check If blood has a density of 1.05 g/mL, how many liters of blood are donated if 575 g of blood are given? 1) L 2) 1.25 L 3) 1.83 L 1) L

Density is the mass per unit volume. Density = mass Volume Example: A block has a volume of 25.3 cm 3. Its mass is 21.7g. Calculate the density of the block. Example: A student fills a graduated cylinder to 25.0 mL with liquid. She then immerses a solid in the liquid; the volume rises to 33.9 mL. The mass of the solid is 63.5 g. What is the density? d = m = 21.7 g___ V 25.3 cm 3 = g/cm 3 Try this on your own!! 7.13 g/mL