General Chemistry Final Exam |Questions with
100% verified Answers
What is the difference between molecular weight and molar mass? - ✔️✔️Molar mass = g/mol
Molecular weight= amu/molecule
....But for practical purposes they are the same thing
What is an "equivalent" ? What about gram equivalent weight? - ✔️✔️asks how many moles of
the thing we are interested in (protons, hydroxide ions, electrons, or ions) will one mole of
reference compound produce--basically, one equivalent = 1 mole of something
Example: 1 Eq = 1 mole HCl or .5 mole H2CO3
When dealing with gram equivalent weight, its the same thing (you are dealing with one mole
of something) but you extrapolate out to the molar mass of a molecule, so equivalents are
being measured in grams
Example: 1 Eq= 1 mol HCl = 36.5g HCl or .5 mole H2CO3 = 31g H2CO3
What is Normality? How do you convert from normality to molarity? - ✔️✔️a measure of the
concentration, given in the units equivalents/L
Molarity and normality are related by the n-factor (# of the species of interest per molecule)
molarity= normality/n
Determine the normality of the following solutions:
a) .25M Phosphoric acid
,b) 95 g Phosphate ion in 100 ml of solution - ✔️✔️a = .75N
b= 30N
What does the law of constant composition state? - ✔️✔️that any pure sample of a given
compound will contain the same elements in an identical mass ratio
What is the difference between empirical formula and molecular formula? - ✔️✔️Empirical
formula gives the most simplified whole-number ratio of the elements in a compound
Molecular formula gives the exact number of atoms of each element in the compound and is a
multiple of the empirical formula
Find the percent composition by mass of sodium, carbon, and oxygen in a sodium carbonate
molecule (Na2CO3) - ✔️✔️Na= 43%
C=11%
O= 45%
Experimental data from the combustion of an unknown compound indicates that it is 28.5%
iron, 24% sulfur, and 49.7% oxygen by mass. What is it's empirical formula? - ✔️✔️Fe2S3O12
What is a combination reaction? - ✔️✔️two or more reactants form one product
A + B --> C
What is a decomposition reaction? - ✔️✔️a single reactant breaks down into two or more
products
A --> B + C
,What is a combustion reaction? - ✔️✔️Involves oxidation (usually with oxygen) of a fuel (usually
a hydrocarbon), forming carbon dioxide and water
Hydrocarbon + O2 --> H2O + CO2
What is a single displacement reaction? Explain how redox reactions are an example of a single
displacement reaction. - ✔️✔️When an atom or ion in a compound is replaced by an atom or ion
of another element
The atoms that are involved in trading places within a compound each have changes in how
many electrons they have, one is reduced (usually the one that leaves) and one is oxidized
(usually the one that replaces)
What is a double displacement reaction? What kinds of products usually form? - ✔️✔️When
elements from two different compounds swap places with each other to form two new
compounds.
This type of reaction occurs when one of the products is removed from the solution as a
precipitate or gas or when two of the original species combine to form a weak electrolyte
What is a neutralization reaction? - ✔️✔️A specific type of double displacement reaction in which
an acid reacts with a base to produce a salt and water
Describe what occurs when zinc nitrate is dissolved in ammonium sulfate - ✔️✔️It is a double
displacement reaction, so it forms zinc sulfate and ammonium nitrate. Zinc sulfide will then
precipitate out of solution as a solid salt.
Identify the reaction type and likely products:
, 2H2 + O2
Al(OH)3 + H3PO4
2H2O + electricity
NaNO3 + CuOH
Zn + AgCl - ✔️✔️combination rxn; forms water
neutralization rxn; forms AlPO4 and H2O
decomposition rxn; forms hydrogen and oxygen
double displacement rxn; forms sodium hydroxide and copper nitrate
Single displacement rxn; forms zinc chloride and free silver
Balance the following reactions. What are the numbers that are placed in front of each atom in
a balanced equation? What do they tell you?
1. ___Fe + ___Cl2 --> ___FeCl3
2. ___Zn + ___HCl --> ___ZnCl2 + ___H2
3. ___C5H2 + ___O2 --> ___CO2 + ___H2O
4. ___Pb(NO3)2 + ___AlCl3 --> ___PbCl2 + ___Al(NO3)3 - ✔️✔️1. 2Fe + 3Cl2 --> 2FeCl3
2. Zn + 2HCl --> ZnCl2 + H2
100% verified Answers
What is the difference between molecular weight and molar mass? - ✔️✔️Molar mass = g/mol
Molecular weight= amu/molecule
....But for practical purposes they are the same thing
What is an "equivalent" ? What about gram equivalent weight? - ✔️✔️asks how many moles of
the thing we are interested in (protons, hydroxide ions, electrons, or ions) will one mole of
reference compound produce--basically, one equivalent = 1 mole of something
Example: 1 Eq = 1 mole HCl or .5 mole H2CO3
When dealing with gram equivalent weight, its the same thing (you are dealing with one mole
of something) but you extrapolate out to the molar mass of a molecule, so equivalents are
being measured in grams
Example: 1 Eq= 1 mol HCl = 36.5g HCl or .5 mole H2CO3 = 31g H2CO3
What is Normality? How do you convert from normality to molarity? - ✔️✔️a measure of the
concentration, given in the units equivalents/L
Molarity and normality are related by the n-factor (# of the species of interest per molecule)
molarity= normality/n
Determine the normality of the following solutions:
a) .25M Phosphoric acid
,b) 95 g Phosphate ion in 100 ml of solution - ✔️✔️a = .75N
b= 30N
What does the law of constant composition state? - ✔️✔️that any pure sample of a given
compound will contain the same elements in an identical mass ratio
What is the difference between empirical formula and molecular formula? - ✔️✔️Empirical
formula gives the most simplified whole-number ratio of the elements in a compound
Molecular formula gives the exact number of atoms of each element in the compound and is a
multiple of the empirical formula
Find the percent composition by mass of sodium, carbon, and oxygen in a sodium carbonate
molecule (Na2CO3) - ✔️✔️Na= 43%
C=11%
O= 45%
Experimental data from the combustion of an unknown compound indicates that it is 28.5%
iron, 24% sulfur, and 49.7% oxygen by mass. What is it's empirical formula? - ✔️✔️Fe2S3O12
What is a combination reaction? - ✔️✔️two or more reactants form one product
A + B --> C
What is a decomposition reaction? - ✔️✔️a single reactant breaks down into two or more
products
A --> B + C
,What is a combustion reaction? - ✔️✔️Involves oxidation (usually with oxygen) of a fuel (usually
a hydrocarbon), forming carbon dioxide and water
Hydrocarbon + O2 --> H2O + CO2
What is a single displacement reaction? Explain how redox reactions are an example of a single
displacement reaction. - ✔️✔️When an atom or ion in a compound is replaced by an atom or ion
of another element
The atoms that are involved in trading places within a compound each have changes in how
many electrons they have, one is reduced (usually the one that leaves) and one is oxidized
(usually the one that replaces)
What is a double displacement reaction? What kinds of products usually form? - ✔️✔️When
elements from two different compounds swap places with each other to form two new
compounds.
This type of reaction occurs when one of the products is removed from the solution as a
precipitate or gas or when two of the original species combine to form a weak electrolyte
What is a neutralization reaction? - ✔️✔️A specific type of double displacement reaction in which
an acid reacts with a base to produce a salt and water
Describe what occurs when zinc nitrate is dissolved in ammonium sulfate - ✔️✔️It is a double
displacement reaction, so it forms zinc sulfate and ammonium nitrate. Zinc sulfide will then
precipitate out of solution as a solid salt.
Identify the reaction type and likely products:
, 2H2 + O2
Al(OH)3 + H3PO4
2H2O + electricity
NaNO3 + CuOH
Zn + AgCl - ✔️✔️combination rxn; forms water
neutralization rxn; forms AlPO4 and H2O
decomposition rxn; forms hydrogen and oxygen
double displacement rxn; forms sodium hydroxide and copper nitrate
Single displacement rxn; forms zinc chloride and free silver
Balance the following reactions. What are the numbers that are placed in front of each atom in
a balanced equation? What do they tell you?
1. ___Fe + ___Cl2 --> ___FeCl3
2. ___Zn + ___HCl --> ___ZnCl2 + ___H2
3. ___C5H2 + ___O2 --> ___CO2 + ___H2O
4. ___Pb(NO3)2 + ___AlCl3 --> ___PbCl2 + ___Al(NO3)3 - ✔️✔️1. 2Fe + 3Cl2 --> 2FeCl3
2. Zn + 2HCl --> ZnCl2 + H2
