CHEM concentrations

Question 1

The amount of solute in a solution

Answer 1

Concentration

Question 2

one strength which have known amounts of solute and solvent in a given quantity of solution.
e.g. Normal Saline Solution: 0.85% NaCL

Answer 2

Standard Solution

Question 3

Qualitative Description

solutions of relatively low concentration

Answer 3

Dilute or Weak

Question 4

• solutions of relatively high concentration

Answer 4

Concentrated or Strong

Question 5

•Quantitative Description

equivalent weight solute
Liter solution

Answer 5

Normality (N)

Question 6

•Quantitative Description
moles solute / Kg solvent

Answer 6

Molality* (m’

Question 7

•Quantitative Description

moles solute / Liter solution

Answer 7

Molarity(M)

Question 8

•Quantitative Description

moles solute / total moles solution

Answer 8

Mole Fraction(χA)

Question 9

%concentration
•% (w/w) =

Answer 9

Mass solute/ mass solution x 100

Question 10

% (w/v) =

Answer 10

mass solute/ volume solution x 100

Question 11

% (v/v) =

Answer 11

volume solute/ volume solution x 100

Question 12

denotes the number of moles of a given substance per liter of solution.
-A capital letter M is used to abbreviate the units of mol/L.

(in units of mol/L, molar, or M) or molar concentration

Answer 12

Molarity

Question 13

Molarity (M) formula

Answer 13

moles solute / liters of solution

Question 14

mol/kg, molal, or m) denotes the number of moles of solute per kilogram of solvent (not solution).
•The term ______ solution is used as a shorthand for a “one _____ solution”, i.e. a solution which contains one mole of the solute per 1000 grams of the solvent.

Answer 14

Molality

Question 15

molality formula

Answer 15

m of solution = mol solute/ kg solvent

Question 16

as a proportion of the total number of moles in a solution.
•are dimensionless quantities.

Answer 16

molar fraction

Question 17

mole fraction (X) formula

Answer 17

X of solution= mol solute/ mol solution

Question 18

denoted “mol %”
•equal to 100% times the mole fraction, is sometimes quoted instead of the mole fraction

Answer 18

mol %= mol solute/ mol solution x100

Question 19

Equivalent weight solute per liter of solution
•The definition of a gram equivalent varies depending on the type of chemical reaction that is discussed - it can refer to acids, bases, redox species, and ions that will precipitate

Answer 19

Normality

Question 20

is the only concentration unit that is reaction dependent.

Answer 20

Normality

Question 21

one equivalent (or equivalent weight) of a substance is the amount of that substance which supplies or consumes one mol of reactive species.

Answer 21

normality calculations

Question 22

normality formula

Answer 22

Normality (N)= Equivalent wt. solute/ liter solution

Question 23

T or F

For Bronsted acids and bases, normality refers to how many moles of H+ or OH- there are per liter.

Answer 23

true

Question 24

T or F
Thus, for hydrochloric acid (HCl) and sodium hydroxide (NaOH) the normality is equal to the molarity.

Answer 24

TRUE

Question 25

t or f But for substances like sulfuric acid (H2SO4) or barium hydroxide Ba(OH)2, the normality is twice the molarity. •For a substances like phosphoric acid (H3PO4) and aluminum hydroxide Al(OH)3, normality would be three times the molarity and so forth.

Answer 25

TRUE

Question 26

denotes the mass of a substance in a mixture as a percentage of the mass of the entire mixture.

Answer 26

% Concentrations

Question 27

% Concentrations formula

Answer 27

•% (w/w) = mass solute/ mass solution x 100

Question 28

t or F Volume-volume percentage (sometimes referred to as percent volume per volume, % v/v) describes the volume of the solute in mL per 100 mL of the resulting solution. This is most useful when a liquid - liquid solution is being prepared, although it is used for mixtures of gases as well.

Answer 28

TRUE

Question 29

used especially in to denote relative proportions in measured quantities; particularly in low-value (high-ratio) proportions at the parts-per-million (ppm), parts-per-billion (ppb), and parts-per-trillion (ppt) level.

Answer 29

Parts Per Notation

Question 30

Since parts-per notations are quantity-per-quantity measures, they are known as dimensionless quantities; that is, they are pure numbers with no associated units of measurement

Answer 30

Parts Per Notation

Question 31

often used in the measure of dilutions (concentrations) for instance, for measuring the relative abundance of dissolved minerals or pollutants in water.

Answer 31

Parts-per notation

Question 32

measure of concentration similar to molarity.

Answer 32

Formal Concentration (F)

Question 33

used when solving chemical equilibrium problems. It is calculated based on the formula weights of chemicals per liter of solution.

Answer 33

Formal Concentration (F)

Question 34

The difference between ______ and molar concentrations is that the formal concentration indicates moles of the original chemical formula in solution, without regard for the species that actually exist in solution. Molar concentration, on the other hand, is the concentration of species in solution.

Answer 34

Formal

Question 35

Reducing the concentration of a solution

Answer 35

Dilution

Question 36

The total number of solutes in the solution remains the same after ________, but the volume of the solution becomes greater, resulting in a lower molarity, ppm, mg/L, or % concentration.

Answer 36

Dilution

Question 37

(t or f) When a solution is diluted, solvent is added to lower its concentration. The amount of solute remains constant before and after the dilution: moles BEFORE = moles AFTER

Answer 37

TRUE

Question 38

(t or f) You dilute a solution whenever you add solvent to a solution. Adding solvent results in a solution of lower concentration. You can calculate the concentration of a solution following a dilution by applying this equation: •CiVi = CfVf •where C is the concentration, V is volume, and the subscripts i and f refer to the initial and final values.

Answer 38

true

Question 39

is a method in chemistry that allows quantitative analysis of the concentration of an unknown acid or base solution.

Answer 39

Titration

Question 40

It makes use of the neutralization reaction that occurs between acids and bases, and that we know how acids and bases will react if we know their formula.

Answer 40

Titration

Question 41

equipment used in a titration are:

Answer 41

Burette •Acid/Base Indicator (the one used varies depending on the reactants) •Erlenmeyer flask •Standard Solution (a solution of known concentration, a common one is aqueous Na2CO3) •Solution of unknown concentration

Question 42

Titration Formula

Answer 42

CaVa = CbVb •Ca = concentration of the acid •Va = volume of the acid •Cb = concentration of the base •Vb = volume of the base

Question 43

There are three types of Titration

Answer 43

1) strong acid and strong base 2) weak acid and strong base 3) strong acid and weak base