Separation
Why are separation techniques important to science
To identify what has been separated, to obtain important and pure substances, to remove unwanted particles.
If a gas has a volume of 4.0 L and a pressure of 2.0 atm, what will its volume be if the pressure is increased to 4.0 atm?
2.0 atm x 4.0 L = 4.0 atm x V2
V2 = 8.0/4.0 = 2.0L
What is a mole?
A fundamental unit in chemistry used to measure the amount of a substance. One more is 6.022x10^23 particles. A mole provides a bridge between the microscopic world of atoms and molecules and the macroscopic world of grams and liters (any of these answers work)
Convert 5.0 miles to kilometers (1 mile = 1.60934 km)
8.05 km
What is heat?
Heat is energy in transit due to a temperature difference
Name one separation technique for solids in liquid mixtures, and one for liquids in liquid mixtures
Solids in liquid: evaporation, distillation, centrifugation, sedimentation, filtration, magnetic separation, fractional distillation
Liquids in liquid: distillation, chromatography, partition separation using a funnel
How are pressure and volume related in Boyle's Law? How are temperature and volume related in Charles Law?
Boyle's: indirectly
Charles: directly
If you have 2 moles of an ideal gas at a temperature of 350 K and a pressure of 1.5 atm, what is the volume of the gas?
PV = nRT
1.5V = 2 x 0.0821 x 350
V = 38.6 = 39 L
1.5 L
What are the there types of heat we discuss?
Sensory heat, latent heat, specific heat capacity
What is magnetic separation and how can it be used
Involves the separation of a magnetic substance from a non-magnetic substance by means of a magnet. Can be used in waste management, removing metal contaminants from pharmaceutical products, magnetic cell separation.
If I have a 3.5 L gas at 345K, what will its temperature be if I increase the volume to 4.8 L?
3.5 x T2 = 345 x 4.8
3.5 x T2 = 1,656
T2 = 473 K
A container holds 0.5 moles of gas at a pressure of 2.0 atm at a temperature of 30 Celsius. What is the volume of the gas?
30 + 273.15 = 303.15
2 x V = 0.5 x 0.0821 x 303.15
V = 6.222 = 6.2 L
Convert 60 inches to centimeters (1 inch = 2.54 cm)
152.4 cm
Conduction: the heat transfer from the handle to your hand
Convection: the movement of the water as it becomes boiling
Radiation: the electromagnetic rays from the stovetop
In filtration, what is the substance that is left behind called? What is the substance that passes through called?
Left behind: residue
Passes through: filtrate
If I have an unknown initial temperature of gas in a 6.4 mL container, and I transfer it to a 5.8 mL container at 47 degrees Celsius at a pressure of 2.0 atm, what was its initial temperature?
Disregard pressure
47 + 273.15 = 320.15
6.4/T1 = 5.8/320.15
2,048.96 = 5.8 x T1
T1 = 353.26K = 350 K
A container holds 3 moles of gas at a pressure of 1.5 atm and a temperature of 40 °C. What is the volume of the gas? If the temperature is increased to 100 °C while keeping the pressure constant, what will be the new volume?
T1 = 40 + 273.15 = 313.15K
T2 = 100 +273.15 = 373.15 K
1.5 V = 3 x 0.0821 x 313.15 = 62.1 L
SECOND PART
62.1 / 313.15 = V2 / 373.15
V2 = 75.3 = 75L
convert 75 miles per hour to meters per second (1 mile = 1609.43 meters)
33.53 m/s
What is the difference between exothermic and endothermic, and give an example of each
Exothermic: heat is released to surroundings. Burning wood, burning gasoline, respiration
Endothermic: heat is absorbed from the surroundings. Photosynthesis, decomposition
Distillation takes advantage of different ____________ ________ in liquids
boiling points
If I have 1.55 L of a gas at a pressure of 65.4 mmHg, what will its new pressure be at a volume of 980 mL?
1.55L/1 x 1000 mL/L = 1550 mL
1550 x 65.4 = 980 x P2
P2 = 103.45 = 103 mmHg
A gas occupies a volume of 5.0 L at a pressure of 1.0 atm and a temperature of 25 °C. How many moles of gas are present?
1.0 x 5.0 = n x 0.0821 x (25+273/15)
n = 0.204 = 0.20 moles
convert 120 km/h to m/s
33.33 m/s
Heat energy is being used to break intermolecular forces rather than to increase the temperature of a substance