Chemistry Final
Which of the following shows a correct Lewis dot structure?
. .N: .
Which particle has the lightest mass?
0 -1 e
What is the pH of a substance that has a hydrogen ion concentration of 1.2 ×10−2 M?
1.00
Chemists can identify the composition of some unknown salts by conducting a flame test. When potassium salts are heated in a flame, a purple color is observed. This is due to the movement of electrons between energy levels. What is the electron configuration of a potassium atom at ground state?
1s2 2s2 2p6 3s2 3p6 4s1
The equation below represents a nuclear reaction. What is the mass number of the missing particle in this reaction? Record your answer and fill in the bubbles on your answer document.
24
How many molecules are in 0.500 mole of N2O5?
3.01×1023 molecules
What volume of 1.0 M sodium phosphate, to the nearest tenth of a liter, must be used to make 4.0 L of 0.80 M sodium phosphate?
3.2
What is the volume of 2.00 moles of chlorine (Cl2) at STP, to the nearest tenth of a liter?
44.8
When the equation below is balanced, what is the coefficient for oxygen? ___C3H8(g)+ ___O2(g)---___CO2(g)+___H2O(g)
5
How many atoms are present in 179.0 g of iridium?
5.606 ×1023 atoms
The diagram below shows a gas with an initial pressure of 3060 mm Hg in a cylinder at a constant temperature. The gas expands inside the cylinder and pushes the piston up. What is the final pressure of the gas after the expansion?
784 mm Hg
A form of technetium-99 has a half-life of approximately 6 hours. Which substance correctly completes the equation above?
99 Ru 44
Which of these is the electron-dot diagram for Br2(l)?
: : :B:B: : :
The diagram below shows a battery giving off a current producing bubbles in two test tubes. Which of the following best shows that the investigation results in a chemical change?
A burning wood splint placed above the mouth of the test tube on the right glows brighter when some gas is released from the test tube.
A sample of a compound is added to distilled water in a clean beaker. A reaction occurs, and the water temperature drops rapidly. Which of the following statements is best supported by this observation?
An endothermic reaction occurred.
Which product balances the chemical equation below? 3AgNO3(aq)+FeCl3(aq)---3AgCl(s)+____
Fe(NO3)3(aq)
The diagram below shows part of Dmitri Mendeleev's original periodic table, with symbols of known elements and their atomic masses. Mendeleev's arrangement of elements is different than that of the modern periodic table. Based on Mendeleev's arrangement, which elements should be placed in the shaded boxes labeled X and Z respectively?
Gallium (Ga), because it has chemical properties similar to those of aluminum (Al), and germanium (Ge), because it has chemical properties similar to those of silicon (Si)
Sodium, mercury, argon, and neon are used in the production of lamps. There are fewer safety guidelines regarding the handling of neon and argon than for mercury and sodium. Which of the following best describes the elements within the group of the periodic table that contains neon and argon gas?
Gaseous at room temperature and mostly unreactive with metals
Which equation represents a neutralization reaction?
H2SO4+2NaOH---Na2SO4+2H2O
What is the formula of the ion hydrogen sulfite, which has a charge of −1?
HSO3 -1
Which of the following best explains why doubling the temperature of an ideal gas in a closed vessel doubles the pressure?
Increasing the temperature causes gas molecules to move more rapidly, striking the vessel walls more frequently and with greater force.
A scientist filters a sample of river water. The data from this process are listed below. These data support which of the following descriptions of the sample?
It is a mixture because solid particles are separated from the river water.
The solubility of an unknown substance was tested during an experiment. Based on the solubility curve information and the results of the experiment, what is most likely the identity of this unknown solute?
KNO3
Which of the following correctly matches a compound with its molecular geometry?
Methane (CH4): tetrahedral
Which of the following diagrams correctly represents the formation of a compound consisting of magnesium and fluorine?
Mg--F --F
Which mixture can be separated through filtration because one of the substances is insoluble in water?
Na2SO4 and SrSO4
Which of the following substances is a strong electrolyte when dissolved in water?
NaNO3
The diagram below represents a nuclear reaction. Which of the following best describes this reaction?
Nuclear fission is occurring because a nucleus is being split into smaller nuclei.
DB. A material safety data sheet (MSDS) for a chemical is shown below. Which of these is the IUPAC name for H3PO4(aq)?
Phosphoric acid
Heart cells require a certain balance of sodium and potassium ions to function. The blood, which is approximately 83% water, carries these two types of ions to the heart. The property of water that allows it to carry ions to the heart is its—
Polarity
What is the chemical formula for disulfur decafluoride?
S2F10
Some students used a variety of procedures to investigate four liquid samples. The students recorded the following information. • When Sample W was cooled, solid particles settled out of the liquid. • The mass and volume of Sample X were measured, and the density of Sample X was calculated to be 1.6 g/mL. • Sample Y was heated, and the temperature was recorded. All the liquid boiled away at the same temperature and left no residue in the container. • When a dilute acid was added to Sample Z, gas bubbles formed and rapidly rose to the surface of the liquid. Based on these observations, which sample was clearly identifiable as a pure substance?
Sample Y
Which of the following includes an example of a chemical property of an element?
Sodium is a solid at room temperature and reacts with other elements
X-ray crystallography is a technique that allows scientists to determine the ionic and atomic radii of elements. Which of these statements correctly describes a trend in ionic or atomic radii in the periodic table?
The atomic radius increases from top to bottom in a group.
Which of these statements is an accurate description of the ionization energies of elements in the periodic table?
The ionization energy of lithium is greater than that of potassium.
Which of these is a postulate of kinetic molecular theory?
The kinetic energy of gas molecules depends on temperature.
Which of the following best explains why CO2 gas is easily compressible but solid CO2 (dry ice) is incompressible?
The molecules of solid CO2 are much closer together than the molecules of CO2 gas.
In a famous experiment conducted by Ernest Rutherford, positively charged alpha particles were scattered by a thin gold foil. Which of the following is a conclusion that resulted from this experiment?
The nucleus is very small and the atom is mostly empty space.
As a distant star moves away from Earth, the light given off by the star has a measurably lower frequency. What happens to the wavelength and energy of the photons of light when the frequency becomes lower?
The wavelength becomes longer, and the energy decreases.
A detail from a label on a bottle of a water-softening agent is shown below. Which inference about the contents of the bottle can best be drawn?
They consist of barium chloride dihydrate.
The graph below shows a solubility curve for ammonia gas and solubility measurements taken at different temperatures. Between which two points did the ammonia solution change from being unsaturated to saturated?
V----W
When zinc is exposed to air, zinc oxide is produced. What happens in this reaction?
Zinc is oxidized, and oxygen is reduced.
What is the electron configuration for an atom of germanium at ground state?
[Ar]4s23d104p2
The following table lists some properties of copper and sulfur. Samples of copper metal and sulfur powder are placed in the same test tube and heated over a Bunsen burner. The resulting substance has the following properties. • Does not conduct electricity • Has a density of 5.6 g/cm3 • Has a metallic luster • Is a black brittle crystalline solid This black substance is classified as —
a compound
Elements in a group of the periodic table are described below. These elements most likely belong to which group?
alkali metals
The table below lists some properties of a sample of lauric acid. Which of these is an intensive property of this sample?
boiling point
The diagram below shows what happens when zinc reacts with hydrochloric acid. Which of these best describes the energy transformation that occurs during this reaction?
chemical energy--thermal energy