Honors Chemistry Cumulative Exam

Which proportionality applies to Avogadro's law?

d) V ∝ n

Which refers to the amount of a solute that will dissolve in a given volume of solvent at a given temperature and pressure?

d) concentrated

A mixture of three noble gases has a total pressure of 1.25 atm. The individual pressures exerted by neon and argon are 0.68 atm and 0.35 atm, respectively. What is the partial pressure of the third gas, helium?

a) 0.22 atm

A student was comparing the solubility of equal amounts of table salt and table sugar at different temperatures.The table below shows the four samples that the student used and the temperature of the water that they were dissolved in. Which of the samples most likely had the highest solubility?

a) 1

Which method would increase the solubility of a gas?

a) Increasing the pressure

Which equation agrees with the ideal gas law?

a) V1/T1 = V2/T2

Which equation is derived from the combined gas law?

a) V1/T1 = V2/T2

A 1-L soda bottle contains dissolved carbon dioxide gas. Which bottle would have the highest concentration of dissolved gas?

a) a bottle that is sealed

An aqueous solution is made from a molecular compound rather than from an ionic compound. If some ions are present in solution, which best describes the solute?

a) a weak electrolyte

Under which conditions does the molar volume of a gas decrease?

a) at 273 K and at 2.0 atm

In which process do ionic compounds separate into their oppositely charged constituent ions when they are dissolved in water?

a) dissociation

Which factor increases the rate of dissolution in an unsaturated solution?

a) increasing the temperature

A chemist dissolved crystals of an unknown substance into water at room temperature. He found that 33 g of the substance can be dissolved into 100 mL of water. What property of the unknown substance was the chemist most likely investigating?

a) its solubility

If the pressure, volume, and the number of moles of a gas are known, which is needed to calculate the universal gas constant from the ideal gas law?

a) the temperature of the gas

A chemist has dissolved a certain substance in water. The chemist knows that more of the substance could be dissolved into the water before it stops dissolving. Therefore, the current solution is (unsaturated/saturated/supersaturated).

a) unsaturated

The molar mass of NaOH is 40.00 g/mol. If 5.20 g NaOH are dissolved in 0.500 L of solution, what is the molarity of the solution?

b) 0.260 M

What is the temperature of 0.80 mol of a gas stored in a 275 mL cylinder at 175 kPa?

b) 7.2 K

Which law states that the pressure and absolute temperature of a fixed quantity of gas are directly proportional under constant volume conditions?

b) Charles's law

Consider a balloon that has a volume V. It contains n moles of gas, it has an internal pressure of P, and its temperature is T. If the balloon is heated to a temperature of 15.5T while it is placed under a high pressure of 15.5P, how does the volume of the balloon change?

b) It stays the same

Which represents the ionization of a strong electrolyte?

b) K3PO4(s) → 3K+(aq) + PO43-(aq)

A student requires 2.00 L of 0.100 M NH4NO3 from a 1.75 M NH4NO3 stock solution. What is the correct way to get the solution?

b) Measure 114 mL of the 1.75 M solution, and dilute it to 2.00 L.

Which is true about dissolving a polar substance in water?

b) The solute particles are carried into the solution.

Shown below is an ion from a salt molecule. Which statement best explains the event?

b) This is hydration, which occurs during dissociation.

Josh prepares a solution by mixing sodium nitrate and water. To calculate the molarity of the solution, Josh should calculate the moles of which substance, and why?

b) sodium nitrate, because it is the solute

The gas in the piston is being heated, and the piston has moved upward. The observation will be summarized in a row of the incomplete table below. What are the variables for this piston?

b) temperature and volume

Nonelectrolytes fail to ionize or dissociate in water because

b) they are very strongly bonded together

What volume would 3.01•1023 molecules of oxygen gas occupy at STP?

c) 11.2 L

Consider this reaction. 2SO2(g) + O2(g) → 2SO3(g) What volume of oxygen gas, in milliliters, is required to react with 0.640 g of SO2 gas at STP?

c) 112 mL

A gas in a rigid container at 25°C has a pressure of 0.96 atm. A change in temperature causes the pressure to increase to 1.25 atm. What is the new temperature of the gas?

c) 115°C

Which solution is the most concentrated?

c) 2.0 mL of 10.5 M H2O2, where H2O2 has a molar mass of 34 g/mol

Decomposition of potassium chlorate (KClO3) produces potassium chloride (KCl) and pure oxygen (O2). The balanced equation for the reaction is as follows. 2KClO3(s) → 2Kcl(s) + 3O2(g) What volume of oxygen gas is released at STP if 10.0 g of potassium chlorate is decomposed? (The molar mass of KClO3 is 122.55 g/mol.)

c) 2.74 L

A student takes a measured volume of 3.00 M HCl to prepare a 50.0 mL sample of 1.80 M HCl. What volume of 3.00 M HCl did the student use to make the sample?

c) 30.0 mL

Consider the reaction. N2(g) + 3H2(g) → 2NH3(g) How many grams of N2 are required to produce 100.0 L of NH3 at STP?

c) 62.5 g

The expression below was formed by combining different gas laws. Which law was used to determine the relationship between the volume and the number of moles in this equation?

c) Avogadro's law

Which law states that the volume of a gas is proportional to the moles of the gas when pressure and temperature are kept constant?

c) Charles's law

The graph below shows how solubility changes with temperature.Which two solutions have similar solubilities at 40°C?

c) Na2HAsO4 and Na2SO4

A student uses 0.0821 L• atm/mol • K as the value of the gas constant. What is most likely true about the variables in the ideal gas law?

c) V has the units of liters, and T has the units of kelvin.

Consider the proportionality below. PV ∝ nT What does this best represent?

c) ideal gas law

Water is dissolved into n-butanol (a polar liquid). Which is the second step at the molecular level as water dissolves into n-butanol?

c) n-Butanol molecules surround water molecules.

Under which conditions will sugar most likely dissolve fastest in a cup of water?

c) sugar crystals with stirring at 15°C

What is the temperature of 0.750 mol of a gas stored in a 6,850 mL cylinder at 2.21 atm?

d) 246 K

The chemical equation for the combustion of acetylene (C2H2) is given below. 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g) What volume of oxygen at STP is required for the complete combustion of 100.50 mL of C2H2?

d) 251.25 mL

Five gases combined in a gas cylinder have the following partial pressures: 3.00 atm (N2), 1.80 atm (O2), 0.29 atm (Ar), 0.18 atm (He), and 0.10 atm (H). What is the total pressure that is exerted by the gases?

d) 5.37 atm

Consider the balanced chemical equation for the combustion of methane (CH4). CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) Given that the molar mass of CO2 is 44.01 g/mol, how many liters of oxygen is required at STP to produce 88.0 g of CO2 from this reaction?

d) 89.6 L

Which is an example of dissociation?

d) Ca3(PO4)2 → 3Ca2+ + 2PO43-

Which law is described by saying that doubling the absolute temperature will double the pressure of a sample of gas in a rigid container?

d) Gay-Lussac's law

The volume of a fixed amount of gas is doubled, and the absolute temperature is doubled. According to the ideal gas law, how has the pressure of the gas changed?

d) It has stayed the same

Which is an example of ionization?

d) Mg(OH)2 → Mg2+ +2OH-

Which is the first step in the dissolving process?

d) The solvent molecules are attracted to particles at the surface of the solute.

The concentration of a solute in a solution is greater than the maximum concentration that is predicted from the solute's solubility. What is the best way to describe this solution?

d) supersaturated