What Conversion?
What conversion factor would get you from moles of a gas to liters of a gas. (@ STP)
1 mol : 22.4 L @ STP
3.57 moles of gas
Table salt (NaCl) poisoning happens when you have ~0.75g of salt per 1 Kg of a persons body weight. How many moles of NaCl would an average high schooler of 68 kg have to consume get salt poisoning?
0.87 moles NaCl
C4H8
Potassium superoxide, KO2, is used in rebreathing masks to generate oxygen according to the reaction below. If the mask contains 0.50 mol KO2 and 0.20 mol water, how many moles of oxygen can be produced? Which is the limiting reagent?
4KO2 + 2H2O → 4KOH + 3O2
0.5 mol KO2 makes 0.375 mol O2
0.20 mol H2O makes 0.30 mol O2 so water is the limiting agent
What conversion factor would get you from moles to atoms?
Avogadro's number 6.022 x 1023 atoms : 1 mol
Scientists have managed to isolate individual atoms in electromagnetic fields. If you have one single atom how many moles of that atom would you have?
1.66 x 10-24 moles of that atom type
Did you know that standard shower heads use 2.5 gallons of water per minute, and are rather inefficient? If you take a 15 minute shower, many moles of water have you used? (1 gallon : 3.785 Liters, 1 liter : 1000mL, 1 mL H2O : 1 gram H2O)
7,885 moles of water per 15 minute shower
A chemical has an empirical formula of CH2NH3 and a molar mass of 93.18 g/mol. What is the molecular formula?
C3H6(NH3)3 or C3H6N3H9
4KO2 + 2H2O → 4KOH + 3O2
If you have 9 grams of water and 64 grams of KO2 which is the limiting agent?
9 grams of water makes 0.75 mol oxygen
64 grams of KO2 makes 0.675 mol oxygen so KO2 is limiting
What conversion factor would get you from moles to molecules?
Avogadro's number 6.022 x 1023 atoms : 1 mol
Table salt (NaCl) poisoning happens when you have ~0.75g of salt per 1 Kg of a persons body weight. This means an 80 Kg person could die and definitely would begin to feel the effects from salt poisoning if they ingested 60 grams of salt. How many moles is 60 grams of NaCl?
1.03 moles NaCl
An average reusable water bottle size is 24 fluid ounces. How many moles of water would that bottle size contain? (1 fl oz : 29.57 mL, 1 ml water : 1 g water)
39.4 moles of water in that bottle size
The common name for dextroamphetamine or 1-phenylpropan-2-amine is its prescription name Adderall. The amphetamine was discovered in 1887 and is a strong central nervous system stimulant. It is used in the treatment of attention deficit hyperactivity disorder, narcolepsy, and obesity. It is 79.95% carbon, 9.692% hydrogen, 10.36% nitrogen, and has a molar mass of 135.204 g/mol. What is the molecular formula?
C9H13N
4KO2 + 2H2O → 4KOH + 3O2
If you have 15 grams of water and 112 grams of KO2 which is the limiting agent and how much of the excess reactant could have been saved?
15 grams of water makes 1.25 mol oxygen so water is excess
112 grams of KO2 makes 1.18 mol oxygen so KO2 is limiting
0.07 moles of oxygen excess is made from 0.84 grams of water that we could have saved/not used
What conversion would get you from moles to grams?
1 mol : molar mass (g)
If you had 1.5 x 1010 molecules would be how many moles of that molecule would you have?
2.49 x 10-14 moles of that molecule
If I have 60 L of nitrogen gas (N2) how many grams of nitrogen do I have?
75.1g N2
A sample of a compound with a formula mass of 34.00 g/mol is found to consist of 5.978% g H and 94.02% O. What is the molecular formula?
H2O2
3AgCN (aq) + Fe (s) → Fe(CN)3 (aq) + 3Ag (s)
If 0.75L of a 1.5M AgCN solution is reacted with excess iron how many grams of pure silver should be produced? If you recover 119 grams of silver what was your percent yield?
121.4 g Ag theoretical gives a 98% yield
What is our conversion factor for dissolved solid in liters of solvent? What are the units for that factor?
Molarity = Moles/Liters
If you needed to make a 5M solution of NaCl (molar mass = 58.44 g/mol) in a 0.250L volumetric flask, how many grams of NaCl would you have to put in that flask?
73.05 g NaCl in the 0.250L flask
NaOH + HCl => NaCl + H2O
According to the reaction above NaOH and HCl react in a 1:1 mole ratio. How many mL of a 1M NaOH solution are required to completely neutralize 500 mL of a 2M HCl solution?
1000 mL of 1M NaOH needed
Serotonin or 5-hydroxytryptamine is a neurotransmitter. Its biological function is complex but it has roles in modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. It is 68.15% carbon, 6.864% hydrogen, 15.90% nitrogen, 9.080% oxygen, and has a molar mass of 176.216 g/mol. What is the molecular formula?
C₁₀H₁₂N₂O
SO2 is a common gas given off in combustion exhaust, and forms acid rain according to two reactions.
2SO2 + O2 => 2SO3 and then SO3 + H2O => H2SO4
If you start with 200g SO2 how many grams of H2SO4 should be produced? If you recover 300g what was your % yield?
306.18 g H2SO4 theoretical with a 98% yield.