Students perform an experiment that instantaneously forms a precipitate. They mix aqueous iron (III) nitrate and sodium hydroxide to produce iron (III) hydroxide and aqueous sodium nitrate.

What is the correct balanced equation for this reaction to show conservation of mass?

What are the correct coefficients if the law of conservation of mass is applied to the decomposition of solid ammonium nitrite to nitrogen gas and liquid water?

The reaction between solid aluminum and liquid bromine is exothermic. This reaction creates the product aluminum bromide.

What equation includes the correct formulas and demonstrates conservation of mass?

Students perform several experiments recording the reactions in lab journals. The students write and balance the chemical equations for each reaction and include the state of matter notations for each compound. The equations are pictured here. Which chemical involved in the student experiments is dissolved in water?

What are the coefficients that would correctly balance this reaction? 
 

__Ni + __C₄H₈N₂O₂ → __Ni(C₄H₈N₂O₂)₂

What is the balanced equation for the combustion of magnesium?

Which coefficients are required to correctly balance the equation, C₂H₂ + O₂ → CO₂ + H₂O?

What are the coefficients that would correctly balance this equation? 
 

__Zn + __K₂CrO₄ → __K + __ZnCrO₄

When solid zinc is dissolved into a solution of copper sulfate, the reaction creates a clear solution of zinc sulfate. In this oxidation-reduction reaction, the zinc atoms are oxidized, and copper (II) ions are reduced to create solid copper.

What type of reaction occurs between zinc and copper sulfate?

Methane is natural gas containing both carbon and hydrogen. What type of reaction occurs when methane reacts with oxygen gas to produce carbon dioxide, water, and energy?

Which equation above represents a precipitation reaction?

A student observes what happens when two different aqueous solutions are mixed in a test tube. Which of the following observations would be most indicative of a precipitation reaction?

Which equation represents a neutralization reaction?

By predicting the outcome of the following reactants mixing together in an aqueous solution, what type of reaction will take place? 

Pb(NO₃)₂ (aq) + 2 KI (aq) →

Which of the following reactions involves the ions of two compounds exchanging places to form two new compounds?

What type of reaction involves a single compound producing two or more simpler substances?

What reaction involves one element replacing an element in a compound that is from the same activity series?

What reaction involves two or more substances combining to form a single compound?

How many Mg atoms are found in 1.00 mole of MgO?

How many atoms of NaCl are present in 11.0 moles?

How many atoms are in a sample containing 4.000 moles of carbon? 

How many atoms are in a 591 g sample of gold?

How many atoms of silicon would there be in a sample that contained 4.66 x 10³⁰ grams?

A three (3.00) mole sample of K₂S would have how many atoms of potassium?

Calculate the number of molecules present in .20 moles of H₂O.

How many Mg ions are present in 3.00 moles of MgCl₂?

A molecule of glucose is comprised of 6 atoms of carbon, 12 atoms of hydrogen, and 6 atoms of oxygen.

What is the molar mass of glucose?

What is the molar mass of MgSO₄?

What is the molar mass of sodium chloride, NaCl?

Describe the process of calculating the molar mass of Li₂S.

A student is conducting an experiment at STP where a solid metal is reacting with an acid solution to produce a hydrogen gas as seen above.  This gas is then collected in a eudiometer, and its volume is measured in milliliters.

Using the diagram of the experiment, determine how many moles of hydrogen gas have been collected in the eudiometer (assuming the gas is still at STP).

A student has a 5.00 gram sample of calcium chloride (CaCl₂) solid.  How many moles of calcium chloride are contained in this sample?

Which of the following is the mass in grams of 4.25 × 10³ mol of N₂?

In the reaction N₂ + 3H₂ → 2NH_3, what is the mole ratio of hydrogen to nitrogen?

In the reaction 2 H₂ + O₂ → 2 H₂O, what is the mole ratio of hydrogen to water?

Calcium hydroxide and hydrochloric acid react to form calcium chloride and water as shown in the chemical reaction.  If the chemicals are present in exactly the correct ratios to fully use all of the ingredients, how many moles of water would be formed from 5 moles of HCl?

 ___Ca(OH)₂ + ___HCl    ​ ___CaCl₂ + ___H₂O

In the reaction 2H₂ + O₂ → 2H₂O, how many moles of oxygen are required to fully react with 6.0 mol of hydrogen?

In the reaction 2RbNO₃ → 2RbNO₂ + O₂, how many moles of O₂ are produced when 5.0 mol of RbNO₃ decompose?

A scientist fills a large, tightly sealed balloon with 75,000 mL of helium at STP. Using significant figures, how many moles of helium are contained within the balloon? 

Use the following chemical equation to answer the question.

4K_(s) + O_2(g) → 2 K₂O_(s)

If a staff member at a laboratory has 12.0 grams of potassium metal, what is the theoretical yield of potassium oxide that the scientist could potentially produce from the reaction with oxygen gas?

In 1860, Robert Boyle was the first to use phosphorus to ignite sulfur-tipped wooden splints that gave rise to our modern matches. One of the ways it can be made involves the chemical reaction of calcium phosphate with carbon and silicon dioxide in a furnace:

2Ca₃(PO₄)₂ + 6SiO₂ + 10C → 6CaSiO₃ + P₄ + 10CO

Refer to the information above. A match manufacturer received a supply of 2.72 × 10⁶ g of silicon dioxide. In order to reduce waste and improve product purity, the match manufacturer must measure precise amounts of the other reactants.

How many grams of calcium phosphate and carbon should the match manufacturer use?

In 1860, Robert Boyle was the first to use phosphorus to ignite sulfur-tipped wooden splints that gave rise to our modern matches. One of the ways it can be made involves the chemical reaction of calcium phosphate with carbon and silicon dioxide in a furnace:

2Ca₃(PO₄)₂ + 6SiO₂ + 10C → 6CaSiO₃ + P₄ + 10CO

Refer to the information above. If you use 100.0 grams of calcium phosphate and an excess of silicon dioxide and carbon, how many moles of phosphorus will be produced?

3CaCl_2(aq) + 2Na₃(PO₄)_(aq) →  Ca₃(PO₄)_2(s)  + 6NaCl_(aq)

Use the balanced equation and the Molar Mass table above to answer the following question.

Suppose 163.9 g of Na₃(PO₄) in solution mixed with sufficient CaCl₂ in solution yields 116 g of Ca₃(PO₄)_2(s) . What is the percent yield of Ca₃(PO₄)_2(s)?

3CaCl_2(aq) + 2Na₃(PO₄)_(aq) →  Ca₃(PO₄)_2(s)  + 6NaCl_(aq)

Use the balanced equation and the Molar Mass table above to answer the following question.

How much Ca₃(PO₄)_2(s)  could be produced in an industrial process if 55.00 g of CaCl₂ in solution reacted completely with sufficient Na₃(PO₄) _(aq)?

A student burns 1.50 mol C₃H₈ according to the following reaction:

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

How many grams of carbon dioxide are produced?

One step in the production of copper is to heat copper (I) sulfide, Cu₂S, with oxygen. This produces copper (I) oxide and sulfur dioxide gas according to the following reaction:

2Cu₂S_(s)  + 3O_2(g) ​→ 2Cu₂O_(s)  + 2SO_2(g)

What is the greatest mass of SO₂ that can be produced from 15.0 mol Cu₂S? 

In order to produce CO₂, a student put a sample of calcium carbonate in a flask and added hydrochloric acid using the following equation:

Ca(CO₃) + HCl → H₂O + CO₂ + CaCl₂

The student finds the mass of CO₂ generated to be 100 g. If the student began with 200 g of HCl and there was ample CaCO₃ left unreacted, what was the percent yield? 

K₂HPO₄ is a highly water-soluble salt. It can be used as a buffering agent, food additive, or fertilizer. The neutralization of phosphoric acid with potassium hydroxide can be used to form potassium hydrogen phosphate.

H₃PO₄ + 2KOH → K₂HPO₄ + 2H₂O

100 g of phosphoric acid (H₃PO₄) is reacted with excess potassium hydroxide. The final mass of K₂HPO₄ produced is found to be 163 g.

What is the percent yield?

One example of rocket fuel is the reaction of hydrazine with dinitrogen tetroxide.  

2N₂H_4(l)  + N₂O_4(g) → 3N_2(g)  + 4H₂O_(g)  + heat

This reaction is hypergolic, meaning it does not need an external ignition source, and highly exothermic. 1.000 liter of hydrazine is reacted with excess dinitrogen tetroxide. The density of hydrazine is 1.021 g/mL, and the molar mass is 32.0452 g/mol.

How many moles of water could be produced? 

Baking soda (sodium bicarbonate) is a compound commonly used in baked goods, as a deodorizer in refrigerators, and as an antacid. Commercial quantities of baking soda are produced by mixing soda ash dissolved in water with carbon dioxide. Baking soda precipitates as a solid from this method:

Na₂CO₃ + CO₂ + H₂O → 2NaHCO₃

How many grams of soda ash would be needed to produce 1.00 kg of sodium bicarbonate?

Carbon tetrachloride is a solvent which is used as a refrigerant and also as a cleaning agent. Today, methane and chlorine are mainly used to produce carbon tetrachloride:
CH₄ + 4Cl₂ → CCl₄ + 4HCl

How many grams of carbon tetrachloride can be produced from reacting 709.0 grams of chlorine (Cl₂) with excess methane?

When sodium is placed in water, the following chemical reaction occurs.

2Na_(s) + 2H₂O _(l) → 2NaOH _(aq) + H_{2 (g)}

If a teacher uses a 0.350 gram sample of sodium metal for a demonstration with excess water, how many liters of hydrogen gas would be produced at STP?

Use the balanced equation below for the combustion of butane to form carbon dioxide and water to answer the following question.

2C₄H_10(g) +13O_2(g) → 8CO_2(g) +10H₂O_(g)

Suppose a grill lighter contains 50.0 g of butane.  How many grams of butane in the lighter would have to be burned to produce 17.9 L of carbon dioxide at STP?

Use the balanced equation below to answer the following question about the reaction of calcium with hydrochloric acid that produces hydrogen.
Ca_(s) + 2HCl_(aq) → Ca^₂+_(aq) + 2Cl^-_(aq) + H_2(g)

What is the theoretical yield in liters of hydrogen at STP if 20.1 g of calcium are completely reacted?

Ammonia and oxygen can react to produce nitrogen and water.
Following is the balanced equation:

4NH_3(g) + 3O_2(g)  2N_2(g) + 6H₂O_(g)

Suppose 17.0 grams of ammonia react completely with oxygen. How many liters of nitrogen will be produced at STP?

Given the combustion reaction C₃H₈ + 5 O₂ ­­→ 3 CO₂ + 4 H₂O, how many liters of carbon dioxide can be produced from 1.00 liter of O₂ at standard temperature and pressure?

Given the following reaction for photosynthesis, 6 CO₂ + 6 H₂O ­­→ C₆H₁₂O₆ + 6 O₂, how many liters of O₂ can be produced from 100 g of water at standard temperature and pressure?

A model of a chemical reaction is shown. Which substance is the limiting reagent in the chemical reaction? 

A chemist wants to recover solid silver by reacting solid copper with aqueous silver nitrate. The chemist uses stoichiometry to determine which reactant is completely used and which is in excess. The chemist's equation and calculations are shown below.

Using this information, identify the limiting reagent.

The products of the reaction CaF₂ + Br₂ → CaBr₂ + F₂ are formed by reacting calcium fluoride with bromine. If equal moles of each reactant were present, what would be the limiting reactant?

The equation demonstrates a reaction of sodium chloride and fluorine.

2NaCl + F₂ → 2NaF + Cl₂

In order for the reaction to proceed, for every two moles of sodium chloride, there must be at least how many mole(s) of fluorine?

In a closed system, equal amounts of ammonia and oxygen react to produce nitrogen monoxide and water. What is the limiting reactant?

4NH₃ + 5O₂ → 4NO + 6H₂O

For the equation SnO₂ + 2H₂ → Sn + 2H₂O, tin (IV) oxide reacts with excess hydrogen to produce tin and water. What is the limiting reactant?

Students held a four-mole strip of magnesium over a flame until a combustion began. Students were provided the balanced chemical reaction for the combustion of magnesium and asked to describe the limiting reactant. 

2Mg + O₂ → 2MgO

Students created diagrams to demonstrate collisions between gas molecules in a container. They drew dots to represent the gas molecules and arrows to indicate the direction and kinetic energy of each gas molecule. Which diagram and explanation best demonstrates the postulates of the kinetic molecular theory of gases?

According to the kinetic molecular theory of gases, the pressure of the gas is due entirely to the ―

Which statement accurately depicts the mass and volume of a gas according to the kinetic molecular theory?

According to the kinetic molecular theory, which statement best describes the motion of gas particles?

Which of the following statements is related to a postulate (assumption) of the kinetic molecular theory of gases?

A teacher asked students to observe a sealed balloon that was held over a pot of boiling water. Students observed steam begin to surround the balloon and heat up the balloon. The students observed that the balloon increased in volume as it was held over the water. The teacher asked each student to provide an explanation of the phenomenon. Samples of student explanations were recorded below.

Which student's explanation correctly explains why the balloons increased in volume?

Which of the following is not one of the postulates of the kinetic molecular theory for ideal gases?

Which of these is a postulate of kinetic molecular theory?

Observe the balloons A and B above.  Both balloons have a temperature of 25.0°C, contain 0.50 moles of gas sealed by the knot at the bottom, and have a volume of 2.2 L.

If balloon A is placed in a freezer with a temperature of -5.50°C, which of the following statements regarding the volumes of the balloons is accurate?

In an experiment with the apparatus shown, the plunger is used to compress helium gas to different volumes. The corresponding volume and pressures (arbitrary units) are measured and displayed in the data table.  What is the best estimate of the pressure if the volume is compressed to a value of 10.0 units?

In an experiment with the apparatus shown, the plunger is used to compress helium gas to different volumes. The corresponding volume and pressures (arbitrary units) are measured and displayed in the table.  Which statement best characterizes the data in the table?

Consider four sealed, rigid containers with the following volumes: 50 mL, 100 mL, 250 mL and 500 mL.  If each of these contains .25 moles of helium gas at standard temperature, which container would have the greatest pressure?

If the temperature of a gas changes, but the number of moles and volume remain constant, which of the following values must also change?

A fixed quantity of gas is placed inside a container of fixed volume at a temperature of 27°C.  The gas has a pressure, P.

Which expression shows the pressure of the gas at 57°C?

The volume of a sample of oxygen is 200.0 mL when the pressure is 3.000 atm and the temperature is 37.0 ^oC.  What is the new temperature if the volume increases to 400.0 mL and the pressure decreases to 2.000 atm?

The volume of a gas is 50.0 mL at 20.0 K.  What will be the new temperature if the gas is compressed to 10.0 mL under constant pressure?

Calculate the approximate volume of a 1.50 mol sample of gas at 15.0^oC and a pressure of 3.75 atm.

A sample of a gas in a rigid container at 30.0°C and 2.00 atm has its temperature increased to 40.0°C.  What will be the new pressure?

Solid sodium carbonate, Na₂CO₃, reacts with sulfuric acid, H₂SO₄, to produce CO₂ gas according to the following equation:

                     Na₂CO_3(s) + H₂SO_4(aq) → CO_2(g) + H₂O_(l) + Na₂SO_4(aq)

During an experiment to produce carbon dioxide gas, a student recorded the following data:

Pressure CO₂ = 708.1 mm Hg

Volume CO₂ = 29.65 mL

Temperature CO₂= 25.5 °C

How many moles of CO₂ were produced?

With pressure, volume, and temperature being known values, the ideal gas law can be used to —

What is the volume of 1 mole of gas at Standard Temperature and Pressure (STP)?

What is the new pressure of 150 mL of a gas that is compressed to 50 mL when the original pressure was 3.0 atm and the temperature is held constant?

A student is making a solution of sodium carbonate (Na₂CO₃).  They mix 0.79 grams of sodium carbonate into 50.0 mL of water. 

What is the molarity of the sodium carbonate solution?

What volume of 0.125 M KMnO₄ is required to yield 0.180 mol of potassium permanganate, KMnO₄?

A sample of 0.0255 mol potassium hydroxide, KOH, was dissolved in water to yield 10.0 mL of solution.  What is the molarity of the solution?

What volume of 2.5M NaOH solution contains 3.25 mol of NaOH?

What is the molarity of a 9.79 L solution that contains 0.400 mol HCl?

In Flint, Michigan, toxic lead metal was found in the water and it needs to be filtered out in order for the city to have clean and safe drinking water.  A company is proposing a solution where they mix negative ions into the water to bond with the Pb⁺² ions and form an insoluble solid that can be filtered out.

Which of the following compounds contains ions that could be used in order to form a precipitate with lead?

Based on the solubility graph above, which of the following substances is the most soluble in water at 40^o C?

In chemistry class, a student wanted to develop solubility rules by reacting various 0.1 M aqueous solutions together to see if a precipitate formed.  His results are pictured. Which of the following conclusions can be made based on the results shown here?

According to the graph above, which salt has a solubility curve which resembles the behavior of gasses in solution?

Students are asked to make statements about the solubility graph above.  Which student does the best job of communicating the general features of the graph?

Refer to the graph above.  In order to have a saturated solution, how many grams of potassium nitrate, KNO₃, need to be dissolved in 100 grams of water at 20°C.

Refer to the above graph. 90 grams of sodium nitrate (NaNO₃) are put into 100 grams of water and stirred. The final mixture has a temperature of 20°C.  

About how many grams of the sodium nitrate dissolved?

The solubility rules for various salts in water indicate most salts of _______ are not soluble in water.

Hard water contains ions, such as calcium and magnesium, which can dry out the skin and hair. Water softeners work to remove some ions and replace them with others, such as sodium or potassium.

What property of water allows it to transport ions?

Why is water used as a solvent in many solutions? 

Electrolytes are important to the body because they contribute to basic functions such as muscle contraction. Electrolyte ions, such as sodium and magnesium, must be balanced correctly in order to maintain bodily functions.

What property of water allows it to act as carrier for these ions? 

What makes water, H₂O, a polar molecule?

Why is water sometimes called the “universal solvent?”

Water can dissolve many substances because ―

A diluted solution of hydrofluoric acid has a volume of 3 L and a molarity of 3 M. If the original solution had a volume of 2 L, what was the initial molarity?

Of an 8 M solution of HCl, 1 L is diluted to 2 M. What is the volume of the diluted solution?

A chemical company is advertising that the vinegar they produce is superior to other company’s vinegar because it contains 1.24 M acetic acid.  An investigation into their techniques shows that in order to make a bottle of Superior’s Vinegar they start with 150 mL of 17.4 M acetic acid and dilute it to a total volume of 2500 mL with distilled water.

Which of the following statements correctly evaluates the claim that Superior’s Vinegar contains 1.24 M acetic acid?

Beginning with commercial grade hydrochloric acid, 1.00 x 10² mL of a 12.4 M HCl is added to water to bring the total volume of the solution to 0.820L.  What is the concentration of this new solution?

To make 2.00 L of 0.300 M sulfuric acid, how many mL of a 1.00 M stock solution should be used?

High-nitrogen fertilizers change the pH of soil for optimal crop production. Students collected soil samples treated with high-nitrogen fertilizers to test the pH.  What conclusion is best supported by the data?   

Potassium hydroxide, also known as lye, dissociates into metal and hydroxide ions in water. The resulting solution is caustic and used for industrial purposes.

What describes the dissociated solution?

Which type of solution has achieved equilibrium between solute and solvent if the solute is still visible after mixing?

Which of the following is the best way to determine if an aqueous solution of sodium acetate (NaC₂H₃O₂) is supersaturated?

A solution that contains the maximum amount of solute that is soluble at a given temperature is said to be —

Any substance that does not conduct electricity when in solution is called a(n) ―

Which of the following statements makes a valid conclusion regarding the graph above?

What will happen to the ability of a solid to dissolve in a liquid if the temperature increases?

What will happen to the ability of a gas to dissolve in a liquid if the temperature increases?

Which of the following would decrease the rate of solution when dissolving a solid in water?

Which of the following would increase the rate of dissolution of a solid in a solution?

Which of the following would result in being able to dissolve a greater amount of gas in a solution?

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?

What is the pH of a solution with a hydrogen ion concentration of 1.3 x 10^-11?

Determine the pH of a solution that has a hydrogen ion concentration of 6.3 x 10^-6.

What does pH measure?

The pH of a basic solution is —

A sample of fruit juice is found to have a hydrogen ion concentration of 2.87 x 10^-4. What would the pH be?

What is the pH of a substance that has a hydrogen ion concentration of 1.2 ×10⁻² M ?

Predict the missing product in the acid-base reaction.

2HBr + Ca(OH)₂ → 2H₂O + _______ 

Predict the missing product in the acid-base reaction.

HCl + NaOH → H₂O + ______

How are acids described according to the Bronsted-Lowry definition?

A student researched some of the properties of H₂CO₃.  Based on the properties described, what type of chemical is H₂CO₃?

A researcher is conducting a titration experiment where they mix hydrochloric acid with barium hydroxide:
___ HCl _(aq) + ___ Ba(OH)_2 (aq) → ___  _____ + ___  _____

Which of the following reactions shows a correctly balanced chemical equation for the titration being performed?

An aqueous solution of sodium hydroxide reacts completely with a solution of hydrochloric acid.  After all the water evaporates from the reaction mixture, what will remain?

During exercise, muscle cells break down glucose to provide energy. This chemical reaction is represented by the following chemical equation.

C₆H₁₂O₆ + 6O₂ --> 6CO₂ + 6H₂O + energy

How does this equation show the conservation of mass?

The unbalanced equation below shows the combustion of methane.

_CH₄ + _O₂ --> _CO₂ + _H₂O

Which series of numbers represents the coefficients necessary to balance the

equation?

Which of these is a decomposition reaction?

What type of reaction is shown below?

2KClO₃ (s) --> 2KCl (s) + 3O₂ (g)

Magnesium chloride has an atomic mass of 94 amu. What is the mass of one mole of magnesium chloride?

Which BEST defines what a mole represents in chemistry?

How many hydrogen atoms are in 2 mol of H₂O?

How many atoms are in a 4.67 g sample of silicon?

The chemical formula for glucose is C₆H₁₂O₆. What is the percent by mass of hydrogen in glucose?

What is the percent of sodium present in sodium hydrogen carbonate, NaHCO₃?

Which of the following is true of a limiting reagent?

I. It is a reactant

II. It limits the amount of product formed

III. It determines the maximum amount of product formed.

What determines the theoretical yield in a chemical reaction?

Solid zinc (II) oxide is added to hydrochloric acid to form zinc (II) chloride in water. How many moles of zinc chloride will be produced when 112 grams of zinc oxide is used?

Antimony is burned in oxygen to form antimony oxide.

4Sb + 3O₂ --> 2Sb₂O₃

How many moles of Sb₂O₃ will be formed when you have 20.0 moles of oxygen gas?

Which graph shows the correct relationship between pressure and volume?

Charles' law describes the relationship between which two quantities?

The graph below represents data collected during a laboratory investigation on the phase changes of water. Which can be concluded from the graph?

Water vapor in the atmosphere condenses to form droplets in clouds. What happens to energy during condensation?

Which property of water allows it to dissolve substances like sodium chloride and glucose but prevents it from dissolving lipids?

All of the planets in the solar system formed at about the same time from a large cloud of gas and dust. How is Earth different from other planets in the solar system?

Based on these rules, what would the precipitate be in the reaction below?

ZnSO₄(aq) + 2AgCl(aq) --> Ag₂SO₄(?) + ZnCl₂(?)

A student mixes oil and water in a flask. After a while, the oil and water separate into two layers. Which statement BEST explains this result?

What is the concentration of a solution if 2.0 moles of sodium chloride is dissolved in 0.50 liter of water?

Which unit listed below is used to measure solution concentration in chemistry?

Which equation can be used to calculate the dilution of a solution?