CHEM 1200 UNCC Exam 3
Hg, Cu got
I, II
Pb (lead) Sn (Tin) Peanut Butter sandwich
II, IV
Chrome, Iron & Blue got
III, II
Permangate
MnO4^-
A sample of propane, C3H8, contains 15.8 moles of carbon atoms. How many total moles of atoms does the sample contain?
(C moles) 15.8 /3 = 5.26 5.26 x 8 = 42.13 (H moles) 42.13 + 15.8 = 57.9 moles
charges
1 nitrates, hyrdoxide,ammonium, chlorates,acetate 2 sulfates,carbonates, chromate,when hydrogen something the charge is reduced by one (PO4^-3 is HPO3^-2) (hydrogen sulfate HSO4^-, sulfate HSO4^-2)
If a sample of carbon dioxide contains 3.8 moles of oxygen atoms, how many moles of carbon dioxide are in the sample?
1.9
Ascorbic acid (vitamin C) contains 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen by mass. Assume a 100-g sample of ascorbic acid. How many moles of carbon, hydrogen, and oxygen are present in a 100-g sample of ascorbic acid? Use the periodic table as needed.
3.407 C , 4.53 H , 3.406 O 40.92/12.01 4.58/1.01 54.5/16
The most common source of copper (Cu) is the mineral chalcopyrite (CuFeS2). How many kilograms of chalcopyrite must be mined to obtain 300. g of pure Cu?
300g (1mol/63.65g) =4.72 mol 4.72 mol (183.54g/ 1 mol) = 866.4358 g 866.4 g ---> 0.866 kg
One mole of oxygen gas has a mass of ________ g.
32.0 (O2, molecular oxygen)
What is the mass of 0.560 moles of chlorine gas?
39.7 (Cl 2) 2(.56 x 35.45)
/Halogens
7a
Lead
Pb2+ lead (II) Pb4+ lead (IV)
*** HC2H3O2/ C2H3O^-
Acetic Acid/Acetate
Ag Silver
Ag^+
Al Aluminum
Al^3+ 3A
Barium Hydroxide
Ba(OH)2
Acetate
C H O 2 3 2
Acetate
C2H3O2^-
What is the pseudoformula of ascorbic acid, given that ascorbic acid contains 3.407 mol of carbon, 4.53 mol of hydrogen, and 3.406 mol of oxygen?
C3.407H4.53O3.406
What is the empirical formula of ascorbic acid, given that the pseudoformula is C3.407H4.53O3.406? Express your answer as a chemical formula.
C3H4O3
Hydrogen bicarbonate
CHOO ^-2 (pronounce SHOOT)
Cyanide
CN^-
H2CO3 intermediate evolves to what
CO2 (Sulfides)
Carbonate
CO3^2-
Carbonate
COOO ^-2
Calcium Hydroxide
Ca(OH)2
H2CO3/ CO3^2-
Carbonic Acid/Carbonate
HClO3/ ClO3^-
Chloric Acid/Chlorate
HClO2/ ClO2^-
Chlorous Acid/Chlorite
Clorite
ClO2^-
Clorate
ClO3^-
Perchlorate
ClO4^-
Hypoclorate
ClO^-
Cobalt ions
Co2+ cobalt (II) Co3+ cobalt (III)
Chromium
Cr2+ chromium (II) Cr3+ chromium (III)
Dichromate
Cr2O7^2-
Chromate
CrO2^2-
CrOOT
CrO2^2-/ Chromate
DIE chromate
Crite seOxyt
Copper ions
Cu+ copper (I) Cu2+ copper (II)
The chemical formula clearly indicates the relationship between the mass of each element in the formula
False
The empirical formula mass must be 25.0 if the molecular formula mass is 250 and n = 5.
False
Iron ions
Fe2+ iron (II) Fe3+ iron (III)
How can you efficiently determine the number of atoms in a sample of an element?
First determine the mass of the sample and then convert it to the number of atoms using Avogadro's number and the molar mass of the element.
Diatomic
H N F O I Cl Br
Sulfides
H2S
*** Hydrobromic Acid
HBr
Hydrogen Carbonate (Bicarbonate)
HCO2^-
*** Hydrochlroic Acid
HCl
Hydroiotic Acid
HI
Hydrogen Phosphate
HPO4^2-
Hydrogen sulfite
HSO3^-
Hydrogen sulfate
HSO4^-
Mercury
Hg22+ mercury (I) Note that this ion consists of 2 Hg+ ions Hg2+ mercury (II)
What is the mass of 1 mol of atoms for an element?
It is equal to the molar mass of the element.
Why is chemical composition important?
It provides an analysis of the amount of an element found within a sample consisting of a certain compound or a mixture of compounds.
Potassium Hydroxide
KOH
Lithium Hydroxide
LiOH
NH4O2 intermediate evolves to what
NH3 (Ammonium)
Ammonium
NH4^+
Nitrite
NO2^-
Nitrate
NO3^-
Nitrate
NOOO^-
Nitrite
NOO^- (noo smaller than nooo)
Sodium Hydroxide
NaOH
*** HNO3/ NO3^-
Nitric Acid/Nitrate
HNO2/ NO2^-
Nitrous acid/Nitrite
Peroxide
O2^2-
Hydroxide
OH^-
How to calculate mass of a single water molecule.
One water molecule = 1 molecule (1 mol/ 6.022 x 10^23 molecules) = 1.660 x 10^-24 mol of H2O 1.660 x 10^-24 mol (18.0 g/ 1 mol) = 2.99 x 10^-23 (Note that is to a negative power, not positive. It will be a very very small decimal.
Phosphate
PO4^3-
*** HClO4/ ClO4^-
Perchloric Acid
Rubudium Hydroxide
RbOH
Sulfur Hydroxide
S(OH)2
H2SO3 intermediate evolves to what
SO2 (Sulites)
Sulfite
SO3^-2
Sulfate
SO4^-2
Tin ions
Sn2+ tin (II) Sn4+ tin (IV)
Stronium Hydroxide
Sr(OH)2
*** H2SO4// SO4^2-
Sulfuric Acid/Sulfrate
H2SO3/ SO3^2-
Sulfurous Acid/Sulfrite
Which of the following statements correctly describes a relationship between empirical formula and molecular formula?
The empirical formula molar mass is less than or equal to the actual molar mass for all compounds
Why is counting them not an option?
They are so incredibly small it makes traditional counting impossible.
Why is it important to be able to calculate an empirical formula from experimental data?
This allows to determine the amounts (relative masses or moles) of the element in an unknown compound.
The empirical formula mass is 18.0 and the molecular formula mass is 90, therefore n = 5.
True
Zn Zinc
Zn^2+
