Practice Exam Answers

Which statement best explains the purpose of using a mole in the measurement of matter?

The volume of a gas decreases to half of its original volume, but the gas maintains the same number of moles and temperature. According to the ideal gas law, what will most likely happen to the pressure?

The chemical equation shows the decomposition of ammonium nitrate open paren NH sub 4 NO sub 3 close paren NH sub 4 NO sub 3 rightarrow cap n sub 2 cap o plus 2 cap h sub 2 cap o A chemist who is performing this reaction starts with 160 point 1 g of NH sub 4 NO sub 3 The molar mass of NH sub 4 NO sub 3 is 80 point 0 3 g over mol ; the molar mass of water open paren cap h sub 2 cap o close paren is 18 point 0 1 g over mol What mass, in grams, of cap h sub 2 cap o is produced?

Consider the reaction. 3 Mg s plus 2 cap h sub 3 PO sub 4 aq rightarrow Mg sub 3 open paren PO sub 4 close paren sub 2 s plus 3 cap h sub 2 g Which statement is true at STP? (The atomic mass of Mg is 24 point 3 1 u )

The pH of lemon juice at 298 cap k is found to be 2 point 3 2 What is the concentration of cap h sub 3 cap o raised to the plus power ions in the solution? Use open bracket cap h sub 3 cap o raised to the plus power close bracket is equal to 10 raised to the negative pH power

Which factor influences both solubility and the rate of dissolution?

Which statement describes the law of conservation of energy?

When ammonium chloride is dissolved in water, the beaker gets cold. Which type of reaction does this describe?

An unknown substance turns methyl orange solution red. This shows that the substance

What overall effect does adding a catalyst have on a chemical reaction?

How does an increase in reactant concentration affect the rate of reaction?

A chemist dilutes a 1 point 0 milliliters sample of 2 point 0 cap m KNO sub 3 by adding water to it. If the concentration of the solution that is obtained is 0 point 0 0 8 0 cap m , what is its volume? Use cap m sub i cap v sub i is equal to cap m sub f cap v sub f

Consider the reaction. 2 Al sub 2 cap o sub 3 rightarrow 4 Al plus 3 cap o sub 2 How many moles of oxygen are produced if 11 point 0 mol of Al are produced?

A solution containing 1 point 1 5 mol benzene dissolved in carbon tetrachloride has a concentration of 0 point 8 6 m How many kilograms of carbon tetrachloride must the solution contain? Use molality is equal to moles of solute over kilograms of solvent

A gas cylinder contains 2 point 0 mol of gas cap x and 6 point 0 mol of gas cap y at a total pressure of 2 point 1 atm. What is the partial pressure of gas cap y ? Use the fraction with numerator cap p sub A and denominator cap p sub cap t is equal to the fraction with numerator n sub A and denominator n sub cap t

For the reaction, the order of reaction for NH sub 4 raised to the plus power is 1 , and the order of reaction for NO sub 2 raised to the negative power is 1 NH sub 4 raised to the plus A q power plus NO sub 2 raised to the negative A q power rightarrow cap n sub 2 times g plus 2 cap h sub 2 cap o l What is the rate law for the reaction?

A weak base is added to water. Which information is required to find the strength of its conjugate acid ?

Which energy changes are associated with a liquid freezing?

Consider the chemical equation in equilibrium. cap A times g plus 2 cap b g if and only if cap c times g plus cap d times g plus heat What will happen to the equilibrium of this reaction if the temperature is increased?

Consider the reaction. 3 cap o sub 2 g long left right arrow 2 cap o sub 3 g At 298 cap k , the equilibrium concentration of cap o sub 2 is 1 point 6 times 10 to the negative 2 power cap m , and the equilibrium concentration of cap o sub 3 is 2 point 8 6 times 10 to the negative 28 power cap m What is the equilibrium constant of the reaction at this temperature?

Consider these intermediate chemical equations. cap p sub 4 times s plus 3 cap o sub 2 g rightarrow cap p sub 4 cap o sub 6 s triangle cap h sub 1 is equal to negative 1 comma 640 kJ cap p sub 4 cap o sub 10 s rightarrow cap p sub 4 times s plus 5 cap o sub 2 g triangle cap h sub 2 is equal to 2 comma 940 point 1 kJ What is the enthalpy of the overall chemical reaction cap p sub 4 cap o sub 6 s plus 2 cap o sub 2 g rightarrow cap p sub 4 cap o sub 10 s ?

What is the main reason that it takes 2 to 3 minutes for the reaction to occur between sucrose and sulfuric acid in the dehydration of sucrose?

During a lesson in physical science about changes of matter, students made ice cream. Among the materials that are required to make ice cream is salt. Which answer choice best explains the role of salt in this activity?

Consider this chemical equation. Mg OH sub 2 plus 2 HNO sub 3 rightarrow Mg open paren NO sub 3 close paren sub 2 plus 2 cap h sub 2 cap o Which is the net ionic equation?

Digby wants to determine how many calories are in his bag of chips. Which calorimeter should he use?

A compound accepts electrons from another substance to form a covalent bond. Which term best describes this compound’s behavior?

The combustion of glucose, cap c sub 6 cap h sub 12 cap o sub 6 s , produces carbon dioxide, CO sub 2 times g , and water, cap h sub 2 cap o g , according to the equation. cap c sub 6 cap h sub 12 cap o sub 6 s plus 6 cap o sub 2 g rightarrow 6 CO sub 2 g plus 6 cap h sub 2 cap o l The enthalpy of the reaction is negative 2 comma 840 kJ What is the heat of combustion, per mole, of glucose?

Brownian motion is not observed in a mixture that includes two phases. Which best identifies the mixture?

Consider the equation. Fe times s plus CuSO sub 4 times aq rightarrow Cu times s plus FeSO sub 4 times aq Which reactant is a substance that is dissolved in solution?