What follows an element's symbol in a chemical formula to indicate the number of atoms of that element in one molecule of the compound?
subscripted number
The chemical formula for an ionic compound represents one
formula unit
What is the correct name for the NO3- ion?
Nitrate
What is the correct formula for copper (i) cyanide?
CuCN
What is the correct name for the compound P2Cl4?
diphosphorus tetrachloride
What is the correct formula for the compound made of magnesium and nitrogen?
Mg3N2
Oxidation numbers are used to indicate the
charge of an ion
What is the oxidation number of nickel in NiCO3?
+2
What is the correct name for the compound Ni2O3 using the Stock system?
Nickel (iii) oxide
What is the oxidation number of phosphorus in the PD4(3-) ion?
+5
What is the mass percentage of cobalt in cobalt (ii) fluoride, CoF2?
60.80%
What is the mass of 4.80 mol of barium hydride, BaH2?
669g
Which of the following molecular formulas does not have the corresponding empirical formula XY2Z?
XYZ
The simplest whole number ratio of moles of each element in a compound is known as the
empirical formula
Changing a subscript in a correctly written chemical formula will
change the formula so that it no longer represents the same compound
Using the Stock system of naming, Cr2(SO4)3 is named
chromium (lll) sulfate
In a polyatomic ion, the algebraic sum of the oxidation numbers of all atoms is equal to
the charge of the ion
The first part of the name of a binary ionic compound is the
cation
The empirical formula may not represent the actual composition of a(n)
molecular compound
The formula for phosphoric acid is
H3PO4
To determine the correct molecular formula of a compound from an empirical formula, one must determine the
formula mass
***Write the oxidation number for the given element:
Sulfur in H2SO4
+6
Oxygen in peroxides (H2O2)
-1
Magnesium in MgO
+2
Silicon in SiCl4
+4
***Write the formulas for the following compounds:
Silicon dioxide
SiO2
Carbon tetriodide
CI4
Tin(lV) chromate
Sn(CrO4)2
Barium hydroxide
Ba(OH)2
***Write the names of the following compounds, using whichever prefix is indicated:
PI3, Stock system
Phosphide (III) iodide
N2O4 Traditional
Dinitride tetraoxide
Fe(NO2)2 Stock system
Iron (II) nitrite
CCl4 Traditional
Carbon tetrachloride
CO Traditional
Carbon monoxide
CuCO3 Stock system
Copper (II) Carbonate
Formulas and Names
Ca 2+ and Cl -
CaCl2 Calcium Chloride
Pb 2+ and CrO4 -2charge
PbCrO4 Lead (II) Chromate
Name ions
38. CN -1charge
cyanide
39. O -2charge
oxide
40. OH -1charge
hydroxide
What is the molar mass of tetraethyl lead, Pb(C2H5)4?
323.2 g
What is the formula mass of copper(ll) chloride, CuCl2?
134.6 u
What is the percentage composition of CuCl2 by mass?
47.25% Cu & 52.75% Cl
What is the mass of 0.240 mol glucose, C6H12O6?
43.2
What is the empirical formula for a sample of a compound that contains
259.2 g F and 40.8 g C?
CF4
The empirical formula for a compound is C2H5 and its formula mass is 58
amu. What is its molecular formula?
C4H10
A sample of a compound is 80% carbon and 20% hydrogen by mass. Its
formula mass is 30 amu. What is the molecular formula?
C2H6