AP Chemistry Final
Consider the numbers 23.68 and 4.12. The sum of these numbers has _____ significant figures, and the product of these numbers has _____ significant figures.
4, 3
A 16.4-g sample of HF is dissolved in water to give 2.0 * 10^2 mL of solution. The concentration of the solution is:
4.1 M
What is the molar mass of ethanol (C2H5OH)?
46.07 g/mol
What mass of NaOH is required to react exactly with 25.0 mL of 2.7 M H2SO4?
5.4 g
Write the steps for the Acid-Base Titration technique
1) Rinse burette with titrant 2) Fill burette with titrant (no air bubbles)--Record initial volume 3) Rinse 3 Erlynmeyer Flasks with DI water 4) Pipet unknown concentration of analyte (10 mL - 30 mL) in flask 5) As we titrate, colorless solution (analyte) becomes faint pink (endpoint)--Record final volume 6) Molarity of titrant --> moles of titrant --> moles of analyte --> molarity of analyte
Calculate the ratio of the effusion rates of N2 and N2O
1.25
Calculate the density of nitrogen at STP.
1.25 g/L
A sample of ammonia has a mass of 43.5 g. How many molecules are in this sample?
1.54 * 10^24 molecules
Which of the following has 61 neutrons, 47 protons, and 46 electrons?
108/47 Ag+
The standard temperature for gases is
0 degrees C
A scientist obtains the number 0.045006700 on a calculator. If this number actually has 4 significant figures, how should it be written?
0.04501
A 7.11-g sample of potassium chlorate was decomposed according to the following equation: 2KClO3 --> 2KCl + 3O2 How many moles of oxygen are formed?
0.0870 mol
Express the volume 781.2 cm^3 in liters.
0.7812 L
A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729 mm above the pool of mercury. What is the pressure of the atmosphere?
0.959 atm
Standard pressure for gases is
1 atm
Which of the following metric relationships is incorrect?
1 gram = 10^3 kilograms
409 Kelvins equals
136 degrees C
You have 88.6 mL of a 2.50 M solution of Na2CrO4(aq). You also have 125 mL of a 2.50 M solution of AgNO3(aq). Calculate the concentration of Na+ after the two solutions are mixed together.
2.07 M
The valve between the 2.00-L bulb, in which the gas pressure is 1.80 atm, and the 3.00-L bulb, in which the gas pressure is 3.00 atm, is opened. What is the final pressure in the two bulbs, the temperature remaining constant?
2.52 atm
A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 70 gram sample of chemical X should contain how many grams of carbon?
20 grams
The Claus reactions, shown below, are used to generate elemental sulfur from hydrogen sulfide. 2H2S + 3O2 --> 2SO2 + 2H2O SO2 + 2H2S --> 3S + 2H2O How much sulfur (in grams) is produced from 21.5 grams of O2?
21.5 g
What is the mass of a 6.761-mol sample of sodium hydroxide?
270.4 g
A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6 degrees C. Determine the temperature at which the volume of the gas is 3.42 L.
278 K
You have 41.6 g of O2 gas in a container with twice the volume as one with CO2 gas. The pressure and temperature of both containers are the same. Calculate the mass of carbon dioxide gas you have in the container.
28.6 g
You have two samples of the same gas in the same size container, with the same pressure. The gas in the first container has a Kelvin temperature four times that of the gas in the other container. The ratio of the average velocity of particles in the first container compared to that in the second is
2:1
Aqueous solutions of barium chloride and silver nitrate are mixed to form solid silver chloride and aqueous barium nitrate. The balanced complete ionic equation contains which of the following terms?
2Ag+(aq)
You mix 55 mL of 1.00 M silver nitrate with 25 mL of 0.84 M sodium chloride. What mass of silver chloride should you from?
3.0 g
Express the number 0.000333 in scientific notation.
3.33 x 10^-4
Bromine exists naturally as a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains
35 protons, 44 neutrons, 35 electrons
Convert 0.3980 m to mm.
398.0 mm
Suppose the reaction of Ca3(PO4)2 + 3H2SO4 --> 3CaSO4 + 2H3PO4 is carried out starting with 153 g of Ca3(PO4)2 and 76.8 g of H2SO4. How much phosphoric acid will be produced?
51.1 g
What is the coefficient for water when the following equation is balanced? As(OH)3 + H2SO4 --> As2(SO4)3 + H2O
6
Avogadro's hypothesis states that:
At the same temperature and pressure, equal volumes of different gases contain an equal number of particles.
A 0.4987-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.9267 g of CO2 and 0.1897 g of H2O. What is the empirical formula of the compound?
C3H3O2
The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the molecular formula of styrene?
C8H8
Which of the following would have a higher rate of effusion that C2H2? N2 O2 Cl2 CH4 CO2
CH4
In the reaction 2Ca(s) + O2(g) --> 2CaO(s), which species is oxidized?
Ca
__________ are substances with constant composition that can be broken down into elements by chemical processes
Compounds
Aqueous solutions of sodium sulfide and copper(II) chloride are mixed together. Which statement is correct?
CuS will precipitate from solution.
Which of the following is NOT a postulate of the kinetic molecular theory?
Gas particles have the most of their mass concentrated in the nucleus of the atom.
Which of the following are INCORRECTLY paired? -Sr, alkaline earth metal -Ta, transition metal -F, halogen -H, noble gas -Ru, transition metal
H, noble gas
Which compound contains the highest percent by mass of hydrogen?
H2O
Write the formula for sulfurous acid
H2SO3
All of the following are weak acids EXCEPT: HCNO HBr HF HNO2 HCN
HBr
Which of the following is a strong acid?
HClO4
The limiting reactant in a reaction
Has the lowest ratio of moles available/coefficient in the balanced equation/moles available
Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0 degrees C and 1 atm pressure. For which gas do the molecules have the highes average velocity?
He
A solid acid HX is mixed with water. Two possible solutions can be obtained. Which of the following is true? I. All of the bonds from the acid are broken. II. Some of the bonds from the acid are broken, some of them are still together.
In case I, HX is acting like a strong acid, and in case II, HX is acting like a weak acid.
The density of gasoline is 0.7025 g/mL at 20 degrees C. When gasoline is added to water:
It will float on top.
What would happen to the average kinetic energy of the molecules of a gas sample if the temperature of the sample increased from 20 degrees C to 40 degrees C?
It would increase
Use the kinetic molecular theory of gases to predict what would happen to a closed sample of a gas whose temperature increased while its volume decreased.
Its pressure would increase.
The first scientist to show that atoms emit any negative particles was
J. J. Thomson
Which of the following compounds in soluble in water? Ni(OH)2 K3PO4 BaSO4 CoCO3 PbCl2
K3PO4
The scientist who discovered the law of conservation of mass and is also called the father of modern chemistry is
Lavoisier
For an ideal gas, which pairs of variables are inversely proportional to each other (if all other factors remain constant)?
T and n
All of the following are characteristics of metals EXCEPT: -good conductors of heat -malleable -ductile -often lustrous -tend to gain electrons in chemical reactions
Tend to gain electrons in chemical reactions
Which of the following is NOT an assumption of the kinetic molecular theory for a gas?
The average velocity of the gas particles is directly proportional to the absolute temperature.
The van der Waals equation, nRT = [P + a(n/V)2](V - nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for
The finite volume of molecules
In the reaction 2Cs (s) + Cl2 (g) --> 2CsCl (s), Cl2 is
The oxidizing agent
Graham's law states that:
The rates of effusion of gases are inversely proportional to the square roots of their molar masses
Which of the following is an example of a quantitative observation?
The temperature of the liquid is 60 degrees C
Dalton's law of partial pressures states that:
The total pressure of a mixture of gases is the sum of the partial pressure of all of the gaseous compounds
Boyle's law states that
The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature
Which statement is NOT correct?
There are only three types of radioactivity known to scientists today
Which metals form cations with varying positive charges?
Transition metals
A metric unit for length is
kilometer
The state of matter for an object that has a definite volume but not a definite shape is
liquid state
The SI unit of pressure is the
pascal
The boiling of water is a
physical change because the gaseous water is chemically the same as the liquid.
In a chemical equation, the ___________ are written on the left side of the arrow, and the ____________ are written on the right side of the arrow.
reactants; products
The following reactions: 2K (s) + Br2 (l) --> 2KBr (s) AgNO3 (aq) + NaCl (aq) --> AgCl (s) + NaNO3 (aq) HCl (aq) + KOH (aq) --> H2O (l) + KCl (aq) are examples of:
redox, precipitation, and acid-base, respectively
The state of matter for an object that has both definite volume and definite shape is
solid state
The ____________ in a chemical equation represent the number of atoms in a particular molecule or formula unit.
subscript
The first people to attempt to explain why chemical changes occur were
the Greeks
Order the four metric prefixes from smallest to largest.
"nano-" < "milli-" < "centi-" < "kilo-"
Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.23% abundance), X-29 (28.976 amu, 4.67% abundance) and X-30 (29.974 amu, 3.10% abundance). What is the identity of element X?
(.9223*27.977) + (28.976*.0467) + (29.974*.0310) = 28.09 Si
The oxidation state of iodine in IO3^- is
+5
What mass of calcium chloride, CaCl2, is needed to prepare 3.950 L of a 1.49 M solution?
653 g
What is the coefficient for oxygen when the following equation is balanced? NH3 + O2 --> NO2 + H2O
7
A piece of zinc with a mass of 12.14 g is submerged in 46.3 cm^3 of water in a graduated cylinder. The water level increases to 48.0 cm^3. The correct value for the density of zinc from these data is?
7.1 g/cm^3
A 20.0 mL sample of glycerol has a mass of 25.2 grams. What is the mass of a 57-mL sample of glycerol?
72 g
The melting point of a certain element is 391 degrees C. What is this on the Fahrenheit scale?
736 degrees F
Explain the main differences between a compound and a mixture.
A compound is made of elements, and a mixture is made up of pure substances, which are made of compounds
Aqueous solutions of barium chloride and silver nitrate are mixed to form solid silver chloride and aqueous barium nitrate. The net ionic equation contains which of the following terms?
Ag+(aq)
Write the chemical formula for aluminum oxide
Al2O3
An example of a pure substance is: elements compounds pure water carbon dioxide all of these
All of these
The first chemist to perform truly quantitative experiments was
Boyle
An ion is formed
By either adding or subtracting electrons from the atom
Give three physical methods used by chemists to separate mixtures and identify the type of mixture best suited for each process
Distillation: Two colorless liquids with one more volatile than the other Filtration: Solid + liquid Chromatography: Solid + liquid OR solid + gas
Write the formula for iron(III) oxide
Fe2O3
Garfield (weighing 24 lbs) took a flight to the moon on the space shuttle. As usual, he stuffed himself with lasagna during the entire flight and napped when he wasn't eating. Much to his delight when he got to the moon he found he only weighed 4 lbs. He immediately proclaimed a quick weight loss diet. Explain the fallacy in his reasoning. Assume gravity on the moon to be about one-sixth that of Earth.
Mass stays the same, but weight changes according to the gravitational force.
A species with 12 protons and 10 electrons is
Mg2+
Write the chemical formula for an ammonium ion
NH4+
Which of the following pairs of compounds can be used to illustrate the law of multiple proportions? NH4 and NH4Cl ZnO2 and ZnCl2 H2O and HCl NO and NO2 CH4 and CO2
NO and NO2
Generally, observed behavior that can be formulated into a statement, sometimes mathematical in nature, is called a(n)
Natural law
Balanced chemical equations imply which of the following?
Numbers of atoms are conserved in chemical change
We generally report a measurement by recording all of the certain digits plus ______ uncertain digit(s).
One
Write the formula for phosphorus trichloride
PCl3
As part of the calibration of a new laboratory balance, a 1.000-g mass is weighed with the following results: Trial Mass 1 1.201 +- 0.001 2 1.202 +- 0.001 3 1.200 +- 0.001 The balance is
Precise but inaccurate
Which of the following is true about the kinetic molecular theory?
Pressure is due to the collisions of the gas particles with the walls of the container.
Complete the following: Because real gas particles have attraction for one another:
Real gases act more ideally at higher temperatures and lower pressures.
Which of the following properties of a real gas is related to the b coefficient in the van der Waals equation?
Real gases consist of molecules or atoms that have volume.
The agreement of a particular value with the true value is called
accuracy
The amount of uncertainty in a measured quantity is determined by
both the skill of the observer and the limitations of the measuring instrument
Which of the following is NOT a unit in the SI system?
calorie
A method of separation that employs a system with two phases of matter, a mobile phase and a stationary phase, is called
chromatography
The _____________ in a balanced equation represent numbers of molecules.
coefficient
Real gases are those that
deviate from ideal behavior.
A solution is also called a
homogeneous mixture
