Which of the following would best be described as a physical change associated with a lab activity conducted in chemistry class?

The table above lists some properties of a sample of lauric acid. which of these is an intensive property of this sample?

An atom of the isotope argon-40 contains how many neutrons in its nucleus?

Which of the following statements correctly explains the mation of atoms and molecules within the different states of matter?

A student was asked to make observaions about a metal sample in his class. He noted the following observations about an unknown sample: Silvery, mass of 71.3 g, volume of 8 cm3, magnetic. Given the table above, what is the most likely identity of the metal?

Some students used a varity of procedures to investigate four liquid samples. The students recorded the following information:

1. when the Sample W was cooled, solid particles settled out of the liquid.
2. the mass and volume of Sample X were measured, and the density of Sample X was calculated to be 1.6 g/mL.
3. Sample Y was heated, and the temperature was recorded. All the liquid boiled away at the same temperatue and left no residue in the container.
4. When a dilute acid ws added to Sample Z, gas bubbles formed and rapidly rose to the surface of the liquid.

Based on these obervations, which sample was clearly identifiable as a pure substance?

Which of the following statements does not accurately describe one of the three classical states of matter?

A scientist filters a sample of river water. The data from this process are listed in the table. Which of the following data descriptions support the data from the table?

Which of the following properties identified by a student in the lab for a sample of sodium chloride is an extensive property?

The above 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:

1. Does not conduct electricity
2. Has a density of 5.6 g/cm3
3. Has a metallic luster
4. Is a black brittle crysalline solid

This black substance is classified as -

Which of the following lists records the states of matter in order from most compressible to least compressible?

C-12 and C-13 are naturally-occurring isotopes of the element carbon. C-12 occurs 98.89% of the time and C-13 occurs 1.108% of the time. What calculation should be used to determine the atomic mass of this element?

Which of the following best describes sublimation?

According to the periodic table, which of these elements will form an ion with a -2 charge?

Which of the following is the correct Lewis dot diagram for the sodium atom?

Chemists can identify the compositon of some unknown salts by conducting a flame test. When potassium salts are heated in a flame, purple color is observed. This is due to the movement of electons between energy levels. What is the electron configuration of a potassium atom at gound state?

A student combines solid and gaseous substances during a laboratory investigation. A new solid substance is formed that has a definite ratio of elements and unique physical properties. Which of these was formed as a result of this student's activity?

Element X has two known naturally occurring isotopes. The mass and relative abundance of each isotope are as follows: isotope A has a relative abundance of 50.57% and a mass of 78.92 (amu) while isotope B has a relative abundance of 49.43% and a mass of 80.92 (amu). What is the average atomic mass of Element X?

Which group might be said to have the following properties:

1. soft silvery-white color
2. good conductor of thermal energy
3. good conductor of electricity
4. atoms contain a single valence electron

What is the electron configuration for an atom of germanium at ground state?

The element Chlorine exists as two naturally occurring isotopes. Cl-35 occurs 75% of the time and Cl-37 occurs 25% of the time. Which of the following calculations should be used to calculate the correct average atomic mass of chlorine?

Which of the following shows a correct Lewis Dot structure?

How many valence electrons does a neutral atom of silicon have?

A metal sample with a high, broad melting point is examined in a lab. The lab determines that the sample can be separated into a simpler substances by melting it and allowing it to separate based on density of its constituents. The sample is a/an?

Which of the following best explains why CO2 gas is easily compressible ut solid CO2 (dry ice) is incompressible?

Which of these are composed of two or more different substances that are chemically combined in a definite ratio?

The empirical formula for a subsance is CH2. If the molecular mass of the substance is 56, the molecular formula is -

The correct name for the compound represented by the formula N₂S₄ is -

The valence shell electron pair repulsion theory is used to predict the molecular shapes of compounds. What would be the shape of the molecule below according to this theory?

BH₃

What is the percentage by mass of aluminum in the compound aluminum oxide (Al₂O₃₎ rounded to the nearest %?

Gold is a valuable neavy metal that has been highly sought after by every known civilization. Besides its beautiful color, gold is also hghly malleable, and extemely ductile which allows it to be formed into a multitude of shapes and hammered into very thin sheets. This property of gold is primarily the result of -

Which of the diagrams below correctly represents sodium chloride?

The correct formula for dinitrogen pentoxide is -

If the following Lewis dot diagram, :X≡X: , were the correct representation for a molecule, then the X would be representative of the element -

Calcium carbonate is the main component of the shells of snails as well as egg shells. It is an insoluble white solid that can be taken in small doses as an antacid. The correct formula for calcium carbonate is -

Which of these statements is an accurate description of the ionization energies of elements in the periodic table?

Carbon dioxide is a compound tht forms with the combustion of carbon in the presence of oxygen. Electron-dot formulas are used to model the bonds that form. Which of these is the electron-dot formula for carbon dioxide?

What is the formula of the ion hydrogen sulfite, which has a charge of -1?

What is the name for the compound CaSO_4?

Which of the following represents the Lewis dot diagram of ammonia (NH₃)?

AlBr₃ can be used as a catalyst in the Friedel-Crafts alkylation reaction. The correct name for the compund represented by the formula AlBr₃ is -

According to the valence shell electron pair repulsion theory, what molecular structure would phosphorous trihydride have?

Data for the atomic radii and ionization energies of elements in group 1 are shown. Which statement regarding these elements is supported by this information?

Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

The chemical equation shown is an example of a -

Mg⁰ → 3e^- + Mg⁺²

^{The reaction above represents which of the following?}

K₃N

What is the correct name for the compound represented by the formula shown above?

Fe + CuCl₂ → FeCl₂ +Cu

This reaction is a -

Electronegativity is the ability of an element to attract electrons in a bond. The element we use as an anchor has the highest electronegativity. This element is -

Which of the following elements has the same Lewis dot structure as Silicon?