6. Chemical Quantities & Aqueous Reactions

Molarity

Concentration and Molarity explained: what is it, how is it used + practice problems

A chemist wants to make 5.5 L of a 0.300 M CaCl2 solution.
What mass of CaCl2 (in g) should the chemist use?

(b) How many moles of KBr are present in 150 mL
of a 0.112 M solution?

The concentration of glucose (C6H12O6) in normal blood is approximately 90 mg per 100 mL. What is the molarity of the glucose?

How to Do Solution Stoichiometry Using Molarity as a Conversion Factor | How to Pass Chemistry

Molarity Example 1

How would you prepare 250 mL of a 0.325 M solution of benzoic acid 1C7H6O22 in chloroform 1CHCl32?

An aqueous NaCl solution is made using 112 g of NaCl diluted
to a total solution volume of 1.00 L. Calculate the molarity of the solution. (Assume a density of
1.08 g>mL for the solution.)

How would you prepare 165 mL of a 0.0268 M solution of benzoic acid 1C7H6O22 in chloroform 1CHCl32?

Household hydrogen peroxide is an aqueous solution containing 
3.0% hydrogen peroxide by mass. What is the molarity of 
this solution? (Assume a density of 1.01 g>mL.)

The sterile saline solution used to rinse contact lenses can be made by dissolving 400 mg of NaCl in sterile water and diluting to 100 mL. What is the molarity of the solution?

Neurotransmitters are molecules that are released by nerve 
cells to other cells in our bodies, and are needed for muscle 
motion, thinking, feeling, and memory. Dopamine is a common 
neurotransmitter in the human brain. 
 
(c) Experiments with 
rats show that if rats are dosed with 3.0 mg/kg of cocaine 
(that is, 3.0 mg cocaine per kg of animal mass), the concentration 
of dopamine in their brains increases by 0.75 mM after 
60 seconds. Calculate how many molecules of dopamine 
would be produced in a rat (average brain volume 5.00 mm3) 
after 60 seconds of a 3.0 mg/kg dose of cocaine.

What volume of 0.200 M ethanol solution contains each 
amount in moles of ethanol? 
c. 1.2 * 10 - 2 mol ethanol

Molarity - Chemistry Tutorial

The density of a 20.0% by mass ethylene glycol (C2H6O2) solution
in water is 1.03 g/mL. Find the molarity of the
solution.

How many moles of solute are present in each of the following solutions? 
(b) 175 mL of 0.67 M glucose (C6H12O6)

Which of the following solutions is more concentrated? (a) 0.500 M KCl or 0.500 mass % KCl in water

(a) How many grams of ethanol, CH3CH2OH, should you
dissolve in water to make 1.00 L of vodka (which is an aqueous
solution that is 6.86 M ethanol)?
(b) Using the density of ethanol (0.789 g/mL), calculate the volume of ethanol you
need to make 1.00 L of vodka.

How many grams of solute would you use to prepare each of the following solutions?
(a) 250.0 mL of 0.600 M ethyl alcohol (C2H6O)

Ammonium chloride, NH4Cl, is a very soluble salt in water. 
(c) If you dissolve 14 g of ammonium chloride in 500.0 mL of 
water, what is the molar concentration of the solution?

The density of acetonitrile 1CH3CN2 is 0.786 g>mL and
the density of methanol 1CH3OH2 is 0.791 g>mL. A solution is made by dissolving 22.5 mL of CH3OH in 98.7 mL of
CH3CN. (c) Assuming that the volumes are additive, what is the molarity 
of CH3OH in the solution?

Calculate the number of moles of solute present in each of
the following solutions: (a) 255 mL of 1.50 M HNO31aq2,

Calculate the molarity of each solution. 
c. 32.4 mg NaCl in 122.4 mL of solution

In 2014, a major chemical leak at a facility in West Virginia
released 28,390 L of MCHM (4-methylcyclohexylmethanol,
C8H16O) into the Elk River. The density of MCHM is 0.9074
g/mL. (a) Calculate the initial molarity of MCHM in the
river, assuming that the first part of the river is 2.00 m deep,
90.0 m wide, and 90.0 m long.

A solution is prepared by dissolving 20.2 mL of methanol
(CH3OH) in 100.0 mL of water at 25 °C. The final volume of the
solution is 118 mL. The densities of methanol and water at this
temperature are 0.782 g>mL and 1.00 g>mL, respectively. For
this solution, calculate the concentration in each unit.
a. molarity

A solution with a final volume of 750.0 mL was prepared by dissolving 30.00 mL of benzene (C6H6, density = 0.8787 g/mL) in dichloromethane. Calculate the molarity of benzene in the solution.

Bronze is a solid solution of Cu(s) and Sn(s); solutions of metals 
like this that are solids are called alloys. There is a range 
of compositions over which the solution is considered a 
bronze. Bronzes are stronger and harder than either copper or 
tin alone. (b) Based on part (a), calculate 
the concentration of the solute metal in the alloy in units of 
molarity, assuming a density of 7.9 g/cm3.

Pure acetic acid, known as glacial acetic acid, is a liquid with
a density of 1.049 g/mL at 25 C. Calculate the molarity of a
solution of acetic acid made by dissolving 20.00 mL of glacial
acetic acid at 25 C in enough water to make 250.0 mL of
solution.

How many moles of solute are present in each of the following solutions? 
(a) 35.0 mL of 1.200 M HNO3

The density of a 16.0 mass % solution of sulfuric acid in water is 1.1094 g/mL at 25.0 °C. What is the molarity of the solution?

How would you prepare 250 mL of a 0.100 M solution of fluoride ions from solid CaF2? Specify the glassware that should be used.

The mass must be converted to moles and the volume to liters.

Convert the mass to moles and divide by the volume in liters.

The volume of the solution must be in liters.

 Molarity is defined as moles of solute divided by the liters of solution. 

What is the molarity of a solution prepared by dissolving 5.00 g of NaCl in 500.0 mL of water?

Calculating Molarity | Chemical Calculations | Chemistry | FuseSchool

Chemistry Basics:  Osmolarity, Osmolality and Tonicity

Practice Problem: Molarity Calculations

What is the molarity of a solution prepared by dissolving 10.19 g of ethanol (CH3CH2OH) in enough water to produce 250.0 mL of solution? (LO 4.1)
(a) 0.8848 M 
(b) 18.08 M
(c) 1.130 M
(d) 0.01808 M

How would you prepare 500 mL of a 0.330 M solution of CaCl2 from solid CaCl2? Specify the glassware that should be used.

A person suffering from hyponatremia has a sodium ion concentration
in the blood of 0.118 M and a total blood volume
of 4.6 L. What mass of sodium chloride would need to be
added to the blood to bring the sodium ion concentration
up to 0.138 M, assuming no change in blood volume?

A railroad tank car derails and spills 36 tons of concen-trated sulfuric acid. The acid is 98.0 mass% H2SO4 and has a density of 1.836 g/mL. 
(a) What is the molarity of the acid?

How many grams of solute would you use to prepare the following solutions? 
(a) 500.0 mL of 1.25 M NaOH

Commercial concentrated aqueous ammonia is 28% NH3 
by mass and has a density of 0.90 g>mL. What is the molarity of this solution?

(c) How many milliliters of a 6.00 M NaOH 
solution are needed to provide 0.350 mol of NaOH?

How many grams of solute would you use to prepare each of the following solutions?
(b) 167 mL of 0.200 M boric acid (H3BO3)

Describe how you would prepare each of the following
aqueous solutions: (a) 1.50 L of 0.110 M 1NH422SO4 solution,
starting with solid 1NH422SO4;

Brass is a substitutional alloy consisting of a solution of
copper and zinc. A particular sample of red brass consisting of 80.0 % Cu and 20.0 % Zn by mass has a density of
8750 kg>m3. (b) What is the molarity of Zn in the solution?

Hypernatremia is a medical condition where a patient has high levels of sodium in their blood, and is the result of the body containing too little water. A patient has a measured sodium level of 165 mM. If 30.0 mL of their blood were drawn, what mass (in ng) of sodium would be present?

How many moles of KCl are contained in each solution?
a. 0.556 L of a 2.3 M KCl solution

Calculate the molarity of each solution.
a. 3.25 mol of LiCl in 2.78 L solution

The concentration of alcohol 1CH3CH2OH2 in blood, called
the “blood alcohol concentration” or BAC, is given in units
of grams of alcohol per 100 mL of blood. The legal definition
of intoxication, in many states of the United States, is that the
BAC is 0.08 or higher. What is the concentration of alcohol,
in terms of molarity, in blood if the BAC is 0.08?

What is the molarity of Na+ in a solution of NaCl whose salinity is 5.6 if the solution has a density of 1.03 g>mL?

Propranolol 1C16H21NO22, a so-called beta-blocker that is used for treatment of high blood pressure, is effective at a blood plasma concentration of 50 ng/L. Express this concen- tration of propranolol in the following units:
(b) Molarity

(c) How many milliliters of 6.1 M HCl 
solution are needed to obtain 0.150 mol of HCl?

Ritalin is the trade name of a drug, methylphenidate, used 
to treat attention-deficit/hyperactivity disorder in young 
adults. The chemical structure of methylphenidate is 
 
(c) Ritalin has a half-life of 3 hours in the blood, 
which means that after 3 hours the concentration in the 
blood has decreased by half of its initial value. For the 
man in part (b), what is the concentration of Ritalin in 
his blood after 6 hours?

Ethylene glycol, C2H6O2, is the principal constituent of auto-mobile antifreeze. If the density of a 40.0 mass % solution of ethylene glycol in water is 1.0514 g/mL at 20 °C, what is the molarity?

A laboratory procedure calls for making 400.0 mL of a 1.1 M
NaNO3 solution. What mass of NaNO3 (in g) is needed?

What volume of 0.200 M ethanol solution contains each
amount in moles of ethanol?
a. 0.45 mol ethanol

What's the Difference Between Molarity and Molality?

How many milliliters of a 0.45 M BaCl2 solution contain 15.0 g of BaCl2?

One brand of laundry bleach is an aqueous solution containing
4.55% sodium hypochlorite (NaOCl) by mass. What is the
molarity of this solution? (Assume a density of 1.02 g>mL.)

(b) Can you identify which
one between 0.10 mol ZnCl2 and 0.1M ZnCl2 contains more
Zn2+ ion? Why?

An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted
to a total solution volume of 2.00 L. Calculate the molarity of the solution. (Assume a density of
1.05 g>mL for the solution.)

Molarity and Dilution

Molarity Made Easy: How to Calculate Molarity and Make Solutions

How would you prepare each of the following solutions? (b) 100 mL of an aqueous solution whose K+ concentration is 0.075 M

Calicheamicin gamma-1, C55H74IN3O21S4, is one of the most 
potent antibiotics known: one molecule kills one bacterial 
cell. Describe how you would (carefully!) prepare 25.00 mL 
of an aqueous calicheamicin gamma-1 solution that could 
kill 1.0 * 108 bacteria, starting from a 5.00 * 10-9M stock 
solution of the antibiotic.

Calculations Involving Solutions in Reactions

How many grams of solute would you use to prepare the following solutions? 
(b) 1.50 L of 0.250 M glucose (C6H12O6)

Hard water contains Ca2+, Mg2+, and Fe2+, which interfere
with the action of soap and leave an insoluble coating on
the insides of containers and pipes when heated. Water softeners
replace these ions with Na+. Keep in mind that charge
balance must be maintained. (a) If 1500 L of hard water contains
0.020 M Ca2+ and 0.0040 M Mg2+, how many moles of
Na+ are needed to replace these ions?

How many moles of KCl are contained in each solution? 
c. 114 mL of a 1.85 M KCl solution

The estimated concentration of gold in the oceans is 1.0 * 10^-11 g/mL.
(a) Express the concentration in mol/L.

2.64 grams of an unknown compound was dissolved in water to yield 150 mL of solution. The concentration of the solution was 0.075 M. What was the molecular weight of the substance?

How many moles of KCl are contained in each solution?
b. 1.8 L of a 0.85 M KCl solution

Residues of the herbicide atrazine 1C8H14ClN52 in water can be detected at concentrations as low as 0.050 mg>L. Express this concentration of atrazine in the following units:
(b) Molarity

Assuming that seawater is an aqueous solution of NaCl, what is its molarity? The density of seawater is 1.025 g/mL at 20 °C, and the NaCl concentration is 3.50 mass %.

How many milliliters of a 0.350 M KOH solution contain 0.0171 mol of KOH?

medical lab is testing a new anticancer drug on cancer cells.
The drug stock solution concentration is 1.5 * 10-9 M, and
1.00 mL of this solution will be delivered to a dish containing
2.0 * 105 cancer cells in 5.00 mL of aqueous fluid. What is the
ratio of drug molecules to the number of cancer cells in the dish?

What is the molarity of each of the following solutions:
(b) 5.25 g of Mn1NO322 # 2 H2O in 175 mL of solution,

Molarity Example 2

What volume in (µL) of 0.125 M HBr contains 0.170 moles HBr?

What volume of 0.200 M ethanol solution contains each
amount in moles of ethanol?
b. 1.22 mol ethanol

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Professor Dave Explains

1. Intro to General Chemistry

2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Solutions

Solutions represent homogeneous mixtures made of 2 or more components that form a uniform composition.&nbsp;

Osmolarity

Osmolarity (ionic molarity) represents the number of moles of ions per liter of solution.&nbsp;

Gas Evolution Equations

A Gas Evolution Equation is a molecular equation that involves the creation of specific gases.&nbsp;

Molecular Equations

Molecular Equations show reacting molecules involved in a chemical reaction.&nbsp;

Complete Ionic Equations

Complete Ionic Equations show aqueous compounds as fully dissociated ions.&nbsp;

Solubility Rules

The Solubility Rules are a convenient set of guidelines to help us determine if a compound will be soluble or insoluble.

Ever wonder how a mass amount such as moles can be converted into the volume amount of liters? Well, molarity serves as the bridge between moles and liters.&nbsp;

Electrolytes

Electrolytes are compounds that can conduct electricity once they are dissolved in a solvent.&nbsp;

Solution Stoichiometry

Solution Stoichiometry deals with stoichiometric calculations in solutions that involve volume and molarity.

Calculate Oxidation Numbers

Calculating Oxidation Numbers is the first pivotal step in understanding redox reactions.&nbsp;

Dilutions

In Dilutions, a solvent (usually water) is added to a concentrated solution.&nbsp;

Redox Reactions

Redox Reactions (oxidation-reduction reactions) involve transference of an electron(s) between reactants.

Activity Series

Activity Series is a list of single displacement reactions in order of reactivity.

Balancing Redox Reactions: Acidic Solutions

Balancing Redox Reactions requires a new approach that accounts for the transfer of electrons between reactants.

Balancing Redox Reactions: Basic Solutions

Balancing Basic Redox Reactions requires all the same steps as balancing in an acidic solution plus an additional step.