Potassium (K) has a smaller atomic mass than argon (Ar) even though the atomic number of potassium is larger than the atomic number of argon. Which of the following best accounts for this observation?

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

A compound has a mass of 2.6632 × 10² g/mol. The number of significant figures in this mass is —

What are the coefficients of the correctly balanced equation?

The correct formula for dinitrogen pentoxide is

When ionic compounds are named, the name of a monatomic anion will end in which of the following suffixes?

When 1 g of sodium chloride (NaCl) is placed in 100 g of water, a solution results. Once the solution is prepared, water is now considered what part of the solution?

What is the name of the compound with the formula PCl₅?

How many electrons does the iron ion have when it forms the ionic compound FeCl₃ ?

Covalent bonds mainly occur between —

What is the volume of the water in this graduated cylinder?

If substance X is a liquid, substance Y is a gas, and substance Z is a solid, and all are at the same temperature and pressure, then the order of increasing strength of their intermolecular forces would be —

If a sample has a mass of 1.25 × 10² g and a volume of 51 mL, what is its density?

What is the empirical formula of the compound with the molecular formula C₆H₁₂?

The diagram shows water molecules in an open beaker and water molecules that have evaporated into the air above the beaker. Which change in this system will increase the rate of evaporation?

A chemist is examining an unidentified element sample with oxidation states of +2, +3, and +6. The element has a shielding effect similar to that of potassium (K). Which statement about the unidentified element is most likely true?

The reaction for the decomposition of ammonia (NH3 ) can be written as shown. If a student starts with 21.7 g of NH3 , how many grams of hydrogen (H2 ) gas will be produced by the reaction?

The product in a balanced reaction is 4Al₂O₃ . Which of the following shows the number of aluminum and oxygen atoms in 4Al₂O₃?

According to the pH scale, which substance is slightly acidic?

Which of these is most likely to form between elements transferring electrons to form oppositely charged particles?

Which of the following is a chemical change?

The table shows the specific heat capacity of four substances. For an equal mass of each substance, which one will require the least amount of heat to raise its temperature from 20°C to 30°C?

What is the volume occupied by 51.0 g of ammonia (NH₃ ) gas at STP?

Which substance will release the greatest amount of heat when 1.00 mol is frozen?

A student hypothesizes that bromine (Br) has different chemical properties from krypton (Kr). The periodic table supports this hypothesis by indicating that —

A mixture of gases with a pressure of 800 mm Hg contains 10% oxygen and 90% nitrogen by volume. What is the partial pressure of the oxygen gas in the mixture?

Which graph best shows the relationship between the volume of a gas and its temperature as the gas pressure remains constant?

One example of an ionic compound is —

A bottle of chemical Q spills on the floor. According to the MSDS, what is the proper response to this accident?

Le Chatelier’s principle describes what happens to a system in equilibrium when a stress occurs. All of the following could shift an equilibrium EXCEPT —

What type of reaction is shown?

Hydrogen chloride is a covalent compound. Which is a correct Lewis dot structure for HCl?

Which is the best use for a fume hood?

Which of the following equations is balanced?

The specific heat of aluminum is 0.900 . How much heat is required to raise the temperature of a 30.0 g block of aluminum from 25.0°C to 75.0°C?

When an electric current is passed through water, the reaction shown takes place. If the arrow were pointing in the opposite direction, what type of reaction would the new reaction represent?

The picture shows a small section of elements from the periodic table. Which element has one more proton than element X?

If 1.0 mole of methane reacts with oxygen to produce carbon dioxide and water, what mass of water is produced?

The melting point of a substance was determined to be 35.7 °C in the laboratory. The accepted value is 34.8 °C. Determine the percent error in this experiment.

How many significant figures are found in 5.0600 x 10⁴?

Ingrid is conducting an experiment to find the most flammable clothing fabric. What process is she utilizing for this inquiry?

An atom contains 70 protons, 70 electrons, and 99 neutrons. What is the mass number?

A student watched her teacher perform the above demonstration. The student was curious how the reaction would result if the amount of sulfuric acid was increased or decreased. To create an experiment, what does the student need to do next?

A chemistry class has decided to conduct a long-term study on the conditions of a dam in regards to the quality of water being held behind the dam. What type of instrument would the class use to monitor the temperature, water flow, and silt levels?

Luke would like to complete a simulation on the reaction between metals and metal ions. What technological tool should Luke use to create the simulation?

An example of a chemical property is —

A neutral atom of aluminum-27 contains —

C₆H₁₂O₆ What is the percent composition of hydrogen found in glucose?

Students want to separate and compare the components of black ink and green ink. Which technique is the best for the students to use?

When compared to sulfur-32, sulfur-34 has more —

When 80 g of sodium hydroxide, NaOH, are dissolved in enough water to make 500 mL of solution, the molarity of the solution is —

The figure demonstrates the proper procedure of —

Four students each took three temperature readings of a sample of water. The actual temperature of the sample was 80.0ºC. Which student’s measurements were both accurate and precise?

A binary covalent compound contains 7 phosphorus elements. What prefix should be used when naming this element?

What is the name for the compound CaSO₄?

Which of these sets of coefficients correctly balances the equation?

If the pH of a solution is 4, what is the pOH?

Which of the following is a mixture?

1s² 2s² 2p⁶ 3s²...

Complete the above electron configuration for calcium.

The correct name for CaCl₂ is —

What is the molar mass of Al(NO₃ )₃?

Which element has the electron configuration of 1s² 2s²

A balloon is filled with 3.8 L of helium gas at STP. Approximately how many moles of helium are contained in the balloon?

A student attempts to measure the specific heat capacity of an unknown liquid through repeated trials. She measures its specific heat capacity, in A student attempts to measure the specific heat capacity of an unknown liquid through repeated trials. She measures its specific heat capacity, in J/g·°C , as 2.14, 2.11, 2.13, 2.12, and 2.11. The specific heat capacity of the liquid should be recorded as —

The chemical equation shown is an example of a —

According to the diagram, during a phase change the temperature —

At what point do a solid and gas exist at equilibrium?

If the temperature changes from point M to point N, at constant pressure, compound X undergoes —

What is the mole ratio for O₂ to SO₃ ?

A sample of metal with a mass of 15.0 g is heated from 75 °C to 105 °C. During this process, 173 J of energy are absorbed by the metal. Determine the specific heat of this metal and use the table above to identify the element name.

Which of these best describes the basis on which new scientific ideas are accepted or rejected?

Based on its position in the periodic table, the element sulfur would be expected to have how many valence electrons?

The number of molecules in 48.0 grams of oxygen gas (O₂ ) is —

A student determined that the density of a sample of tin is 8.00 g/mL, when the actual density of tin is 7.28 g/mL. What was the percent error in the student’s calculation?