Chemistry Final Exam
What are the standard conditions of temperature and pressure?
1 atm pressure and 0 Celsius
Avogadro's number
6.022 x 10^23
Write the electron configuration for argon, atomic number 18
1s2 2s2 2p6 3s2 3p6
What number should be written in front of Na to balance the equation Na + MgCl2 -> NaCl + Mg?
2
How many moles of platinum are equivalent to 1.20 x 10^24 atoms?
2 moles
Determine the number of moles in 100. g of potassium. The molar mass of potassium is 39.10 g/mol
2.55 moles
What is the molar volume of a gas at a standard temperature and pressure?
22.4 L/mol
What number should be written in front of O2 to balance the equation 4 Al + O2 -> Al2O3
3
What is the general form for a single-replacement reaction?
A + BX -> AX + B
Why do chemists work with moles instead of individual atoms?
A mole is a collection of atoms large enough to measure while an individual is too small to measure
What is the general form for a double-replacement reaction?
AX + BY -> AY + BX
What is the empirical formula of a compound whose molecular formula is C2Cl6?
CCl3
The word equation "magnesium reacts with chlorine to produce magnesium chloride" would be represented by which of the following formula equations?
Mg + Cl2 -> MgCl2
How would you describe the solution of the slat formed form the reaction of a weak acid and a strong base?
basic solution
In a reaction in which hydrogen reacts with oxygen to produce water, which substances are the reactants?
both hydrogen and oxygen
Which of the following normally exists as a diatomic molecule?
chlorine
Given that the reaction of CuCl2 + Mg -> Cu + MgCl2 occurs, what can you conclude?
copper is less active than magnesium
The characteristics of gases needed to describe a gas completely include all of the following except
density
When a sample of a gas is kept at constant pressure, the volume and kelvin temperature of the gas are
directly proportional
What kind of reaction is represented by the equation CH4 + 2 O2 -> CO2 + 2 H2O?
double replacement
Because acids and bases are conductors of electricity, they are referred to as
electrolytes
Explain the term empirical formula. What is the empirical formula of strontium bromide, SrBr2
empirical formula shows the smallest whole-number mole ratio of the different atoms in the compound. SrBr2
At the same temperature and pressure, equal volumes of different kinds of gases contain
equal numbers of molecules
If the temperature and pressure of equal volumes are kept constant, the number of particles of each gas are
flexible in some way and can expand or contract
Two simplifying, but false, assumptions of the ideal gas law are that gas particles exert no attractive forces upon one another and gas particles
have no volume of their own
The correct name of the acid HBr is
hydrobromic acid
The reactions of acids with metals produces the gas
hydrogen
The reaction of the anions and cations of slats with water to from acid or base solutions is called
hydrolysis reaction
Explain how industrial processes create acid rain
industrial processes produce compounds that dissolve in atmospheric water in clouds creating acidic solutions that fall to the ground
What kind of substance is represented by a formula unit?
ionic
Differentiate between an ionic compound and a molecular compound
ionic compound is composed of positive and negative ions combined so that the number of positive and negative charges are equal. molecular compound is a chemical compound whose simplest units are molecules
The relative strengths of acids are determined by the extent to which the acid particles
ionize in water solutions
Why can water dissolve NaCl, whereas hexane cannot?
it is a polar solvent, water is attracted to both anions and cations
What temperature scale must be used when working with the ideal gas equation?
kelvin
The temperature scale that has absolute zero as its zero point is the
kelvin scale
Solution concentration as moles of solute/kilograms of solvent is known as
molality
Which concentration unit is used when calculating colligative properties relating to boiling point elevation?
molality
The molar mass of aluminum is 26.98 g/mol and the molar mass of oxygen is 16.00 g/mol. Calculate the molar mass of Al2O3
molar mass is 101.96
The number of atoms of an element equal to the number of atoms in exactly 12.0 grams of carbon-12 is called a
mole
What is the molecular formula of a compound whose empirical formula is CH?
need more information
What is the correct name of the acid HNO2
nitrous acid
Assuming that zinc is a more active metal than lead, what will happen if a lead metal strip is placed into a solution of zinc (11) nitrate?
nothing will happen, there will be no reaction
In a molecule of acetic acid, HC2H3O2, the acidic hydrogen is the hydrogen bonded to a(n)
oxygen atom
A substance that is formed by a chemical reaction is called
product
A solution that contains as much solute as can possibly be dissolved under the existing conditions is said to be
saturated
In a neutralization reaction, the individual properties of the acid and base
are destroyed
In a chemical equation, the symbol that takes the place of the world yields is a
arrow
The sum of the percentages in the percent composition of a substance equals
100
How many atoms of oxygen are represented in 2 Ca(NO3)2?
12
Why does the last electron of potassium enter the 4s level rather than the 3d level?
4s levels have lower energies than the 3rd so it's easier to fill up
Determine the mass in grams of 5.00 mols of oxygen. The molar mass of oxygen is 16.00 g/mol
80 grams
Explain the significance of Avogadro's constant, 6.022 x 10^23. What is the relationship between it and the molar mass of oxygen, 16.00g/mol?
Avogadro's constant is the number of particles in 1 mol of a substance. Because the molar mass of oxygen= 16 g/mol, the mass of 1 mol of 6.022 x 10^23, oxygen atom's is 16.00 g
What is the empirical formula of water?
H2O
How has Dalton's theory about atomic particles been modified by modern science?
We now know about isotopes, atoms are just not solid they have electrons, protons, neutrons, and empty space
Write the electron configuration for strontium
[Kr] 5s2
Air, the gas we are most familiar with, consists of
a mixture of several different types of gases
A substance that can act as either an acid or a base is described as
amphoteric
On the subatomic level, why do some substances undergo certain chemical reactions?
some substances undergo certain chemical reactions on the subatomic level due to the nucleus. the nucleus contains protons and neutrons but on the outside there is a cloud of electrons. due to the subatomic level the electrons will start to change causing a reaction. it depends on the substance and what it contains that will affect the reaction. the substances will then be changed to something new.
The origin of the word acid relates to acids' taste, which is best described as
sour
The acid that is often called the "King of Chemicals" is
sulphuric acid
To determine the concentration of a solution in molarity units, you need to know all of the following except
the mass of the solvent
The electron configuration for nitrogen is 1s2 2s2 2p3. What does the 3 in 2p3 mean?
the number of electrons
What do quantum numbers describe?
the properties of atomic orbitals and the properties of electrons in orbitals
What determines the behavior of an amphoteric compound?
the strength of the acid or base with which it is reacting
Why do most atoms form chemical bonds?
they become more stable bonded together
In a chemical reaction, what is the relationship between the total mass of the reactants and the total mass of the products?
they must be equal
Explain why scientists use resonance structures to represent some molecules
to represent ions or molecules that cannot be represented by a single lewis structure
Which of the following characteristic of a Bronsted-Lowry base?
unshared pair of electrons
Acidic hydrogens are usually bonded to elements that attract electrons
very strongly
Which of the following is not an important factor influencing solubility?
volume of the solvent
In balancing a chemical equation, which of the following are you allowed to do?
write coefficients
