Chemistry Final Exam Flashcards

Questions and Answers

A chemical formula for a molecular compound represents the composition of:

a compound

a molecule (correct)

a solution

an element

How many atoms of fluorine are present in a molecule of carbon tetrafluoride, CF4?

What is the formula for zinc fluoride?

ZnF2

Name the compound Zn3(PO4)2.

zinc phosphate Signup and view all the answers

Name the compound KClO3.

potassium chlorate Signup and view all the answers

Name the compound Fe(NO3)2.

iron(II) nitrate Signup and view all the answers

Name the compound CF4.

carbon tetrafluoride Signup and view all the answers

Name the compound N2O3.

dinitrogen trioxide Signup and view all the answers

What is the formula for silicon dioxide?

SiO2 Signup and view all the answers

What is the formula for dinitrogen trioxide?

N2O3 Signup and view all the answers

What is the sum of the atomic masses of all the atoms in a formula for a compound?

formula mass Signup and view all the answers

What is the formula mass of ethyl alcohol, C2H5OH?

46.08 amu Signup and view all the answers

What is the formula mass of (NH4)2SO4?

132.16 amu Signup and view all the answers

The molar mass of LiF is 25.94 g/mol. How many moles of LiF are present in 10.37 g?

0.3998 mol Signup and view all the answers

How many Mg2+ ions are found in 1.00 mol of MgO?

6.02 X 10^23 Signup and view all the answers

What is the percentage composition of CF4?

13.6% C, 86.4% F Signup and view all the answers

A formula that shows the simplest whole-number ratio of the atoms in a compound is the:

empirical formula Signup and view all the answers

What is the empirical formula for a compound that is 53.3% O and 46.7% Si?

SiO2 Signup and view all the answers

A compound contains 259.2 g of F and 40.8 g of C. What is the empirical formula for this compound?

CF4 Signup and view all the answers

A compound contains 64 g of O and 8 g of H. What is the empirical formula for this compound?

H2O Signup and view all the answers

What is the empirical formula for a compound that is 36.1% Ca and 63.9% Cl?

CaCl2 Signup and view all the answers

A compound contains 27.3 g of C and 72.7 g of O. What is the empirical formula for this compound?

N2O5 Signup and view all the answers

A compound's empirical formula is N2O5. If the formula mass is 108 amu, what is the molecular formula?

N2O5 Signup and view all the answers

A compound's empirical formula is NO2. If the formula mass is 92 amu, what is the molecular formula?

N2O5 Signup and view all the answers

What is the small whole number that appears in front of a formula in a chemical equation?

a coefficient Signup and view all the answers

A chemical equation is balanced when the:

same number of each kind of atom appears in the reactants and in the products Signup and view all the answers

Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen?

C + O2 -> CO2 Signup and view all the answers

In the chemical equation 2Mg(s) + O2(g) -> 2MgO(s), what does Mg represent?

magnesium Signup and view all the answers

In an equation, the symbol for a substance in water solution is followed by:

(aq) Signup and view all the answers

Which coefficients correctly balance the formula equation CaO + H2O -> Ca(OH)2?

1,1,1 Signup and view all the answers

What is the balanced equation for the combustion of sulfur?

S(s) + O2(g) -> SO2(g) Signup and view all the answers

In what kind of reaction do two or more substances combine to form a new compound?

synthesis reaction Signup and view all the answers

In what kind of reaction does a single compound produce two or more simpler substances?

decomposition reaction Signup and view all the answers

The equation A + BX -> AX + B is the general equation for a:

single-displacement reaction Signup and view all the answers

The reaction represented by the equation 2Mg(s) + O2(g) -> 2MgO(s) is a:

synthesis reaction Signup and view all the answers

The reaction represented by the equation Mg(s) + 2HCl(aq) -> H2(g) + MgCl2(aq) is a:

single-displacement reaction Signup and view all the answers

The reaction represented by the equation 2HgO(s) -> 2Hg(l) + O2(g) is a(n):

decomposition reaction Signup and view all the answers

In the equation 2Al(s) + 3Fe(NO3)2(aq) -> 3Fe(s) + 2Al(NO3)3(aq), iron has been replaced by:

aluminum Signup and view all the answers

The ability of an element to react is the element's:

activity Signup and view all the answers

An element in the activity series can replace any element:

below it on the list Signup and view all the answers

Predict what happens when calcium metal is added to a solution of magnesium chloride.

calcium chloride Signup and view all the answers

Predict what happens when nickel is added to a solution of potassium chloride.

no reaction occurs Signup and view all the answers

Which of the following would not be studied in the branch of chemistry called stoichiometry?

the amount of energy required to break the ionic bonds in calcium fluoride Signup and view all the answers

A balanced chemical equation allows one to determine the:

mole ratio of any two substances in the reaction Signup and view all the answers

Each reaction stoichiometry problem requires using a:

chart of electron configuration Signup and view all the answers

In the reaction represented by the equation C + 2H2 -> CH4, what is the mole ratio of hydrogen to methane?

2:1 Signup and view all the answers

In the reaction represented by the equation N2 + 3H2 -> 2NH3, what is the mole ratio of hydrogen to ammonia?

3:2 Signup and view all the answers

The Haber process for producing ammonia commercially is represented by the equation N2(g) + 3H2(g) -> 2NH3(g). To completely convert 9.0 mol hydrogen gas to ammonia gas, how many moles of nitrogen gas are required?

3.0 mol Signup and view all the answers

For the reaction represented by the equation 2H2 + O2 -> 2H2O, how many moles of water can be produced from 6.0 mol of oxygen?

12 mol Signup and view all the answers

For the reaction represented by the equation 2H2 + O2 -> 2H2O, how many grams of water are produced from 6.00 mol of hydrogen?

108 g Signup and view all the answers

For the reaction represented by the equation SO3 + H2O -> H2SO4, how many grams of sulfur trioxide are required to produce 4.00 mol of sulfuric acid in an excess of water?

320 g Signup and view all the answers

For the reaction represented by the equation 2HNO3 + Mg(OH)2 -> Mg(NO3)2 + 2H2O, how many grams of magnesium nitrate are produced from 8.00 mol of nitric acid, HNO3, and an excess of Mg(OH)2?

593 g Signup and view all the answers

For the reaction represented by the equation Cl2 + 2KBr -> 2KCl + Br2, how many grams of potassium chloride can be produced from 300.g each of chlorine and potassium bromide?

188 g Signup and view all the answers

To determine the limiting reactant in a chemical reaction, one must know the:

available amount of each reactant Signup and view all the answers

To determine the limiting reactant in a chemical reaction involving known masses of A and B, one could first calculate:

the number of moles of B and the number of moles of A available Signup and view all the answers

What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?

percentage yield Signup and view all the answers

What is the measured amount of a product obtained from a chemical reaction?

actual yield Signup and view all the answers

What is the maximum possible amount of product obtained in a chemical reaction?

theoretical yield Signup and view all the answers

A chemist interested in the efficiency of a chemical reaction would calculate the:

percentage yield Signup and view all the answers

If the percentage yield is equal to 100%, then:

the actual yield is equal to the theoretical yield Signup and view all the answers

For the reaction represented by the equation CH4 + 2O2 -> 2H2O + CO2, calculate the percentage yield of carbon dioxide if Laura Buckley and Andrea Case react 1000.g of methane with excess oxygen and find that they have produced 2300.g of carbon dioxide.

83.88% Signup and view all the answers

According to the kinetic-molecular theory, gases condense into liquids because of:

forces between molecules Signup and view all the answers

The kinetic-molecular theory explains the behavior of:

solids, liquids, and gases Signup and view all the answers

Unlike in an ideal gas, in a real gas:

the particles exert attractive forces on each other Signup and view all the answers

According to the kinetic-molecular theory, particles of an ideal gas:

neither attract nor repel each other but collide Signup and view all the answers

What determines the average kinetic energy of the molecules of any gas?

temperature Signup and view all the answers

Which is an example of effusion?

air slowly escaping from a pinhole in a tire Signup and view all the answers

What happens to the volume of a gas during compression?

the volume decreases Signup and view all the answers

Study Notes

Chemical Formulas and Composition

Chemical formula denotes the composition of a molecule.
Example: In carbon tetrafluoride (CF4), there are 4 fluorine atoms.

Common Chemical Compounds

Zinc fluoride's formula is ZnF2.
The compound Zn3(PO4)2 is named zinc phosphate.
KClO3 is referred to as potassium chlorate.
Fe(NO3)2 is known as iron(II) nitrate.
CF4 corresponds to carbon tetrafluoride.
N2O3 is named dinitrogen trioxide.
The formula for silicon dioxide is SiO2.

Formula Mass and Molar Mass

The term "formula mass" refers to the total atomic mass of all atoms in a compound.
Ethyl alcohol (C2H5OH) has a formula mass of 46.08 amu.
The formula mass of ammonium sulfate ((NH4)2SO4) is 132.16 amu.
Molar mass of LiF is 25.94 g/mol; 10.37 g of LiF corresponds to about 0.3998 mol.

Empirical Formulas

Empirical formulas represent the simplest whole-number ratio of atoms in a compound.
The empirical formula for a compound composed of 53.3% O and 46.7% Si is SiO2.
For a compound with 259.2 g of F and 40.8 g of C, the empirical formula is CF4.
A compound containing 64 g of O and 8 g of H has the empirical formula H2O.
The empirical formula for a compound made of 36.1% Ca and 63.9% Cl is CaCl2.

Chemical Reactions and Balancing Equations

A chemical equation is balanced when each type of atom is equal on both sides.
In the equation 2Mg(s) + O2(g) → 2MgO(s), Mg is the magnesium reagent.
The balanced equation for oxidation of sulfur is S(s) + O2(g) → SO2(g).
Synthesis reactions occur when two or more substances create a new compound, while decomposition reactions break down a compound into simpler components.

Stoichiometry and Moles

Stoichiometry involves calculating the mole ratio of substances in a reaction.
In the reaction N2 + 3H2 → 2NH3, the mole ratio of hydrogen to ammonia is 3:2.
The Haber process requires 3.0 moles of nitrogen gas to completely convert 9.0 moles of hydrogen gas to ammonia.

Yield and Efficiency in Reactions

Actual yield refers to the measured amount of product from a chemical reaction.
Theoretical yield indicates the maximum possible product.
Percentage yield compares actual yield to theoretical yield expressed as a percentage.
A 100% yield indicates actual equals theoretical yield.

Kinetic-Molecular Theory

The kinetic-molecular theory describes the behavior of solids, liquids, and gases.
Real gases differ from ideal gases due to intermolecular forces.
Changes in temperature directly affect the average kinetic energy of gas molecules.
Effusion is exemplified by air escaping from a punctured tire.

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Test your knowledge of molecular compounds and their formulas with these flashcards. Each flashcard provides a term related to chemistry, along with its specific definition. Perfect for reviewing essential concepts before your final exam!