مراجعه كيمياء 110 دوري الاول

DR.AZZA ABOSAIF (( 0560267333 ) - REVISION COURCE OF CHEMISTRY 110 (1ST TERM-1ST TEST )

CHAPTER 3:-

Sample problems :-

1- How many moles are in 24 g of k ?

2- How many atoms are in 286 g of k ?

3- What is the weight of 66 mole of k atoms ?

4 – how many moles are in 3x1023atoms of k ?

1 MOLE === ATOMIC MASS === AV.#


Sample problems :-

1- How many moles are in 66 g of CH4?

2- How many molecules are in 286 g of CH4 ?

3- What is the weight of 66 mole of CH4 molecules ?

4 – how many moles are in 3x1023MOLECULES of H2O ?

1 MOLE === ATOMIC MASS === AV.#


How many H atoms are in 68 g of H2SO4 ?

How many O atoms are in 66 moles of H3PO4 ?

STCHIOCHEMTRY :-

H2 + O2 H2O

1- Balance equation

2- Describe the chemical equation :

H2 + O2 H2O Moles

# weight

volume

Part of whole:-


3.7

A process in which one or more substances is changed into one

or more new substances is a chemical reaction.

A chemical equation uses chemical symbols to show what

happens during a chemical reaction.

If 209 g of methanol are used up in the combustion, what mass of water is produced?

Methanol burns in air according to the equation

2 CH3OH + 3 O2 2 CO2 + 4 H2O


LIMITING REAGENT :-

…………………………………………………………………………………………………

…………………………………………………………………………………………………

………………………………………………………………………………………………..

EXCESS REAGENT :-

…………………………………………………………………………………………………

…………………………………………………………………………………………………

………………………………………………………………………………………………..

EXAMPEL:- from the text book :-


Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark-brown gas:

2NO(g) + O2(g) 2NO2(g)

In one experiment 0.886 mole of NO is mixed with 0.503 mole of O2. Calculate the number of

moles of NO2 produced (note: first determine which is the limiting reagent).

A) 0.886 mol

B) 0.503 mol

C) 1.01 mol

D) 1.77 mol

Theoretical Yield is the amount of product that would

result if all the limiting reagent reacted.

Actual Yield is the amount of product actually obtained

from a reaction.

% Yield = Actual Yield

Theoretical Yieldx 100

3.10

Reaction Yield


The mole (mol) is the amount of a substance that

contains as many elementary entities as there

are atoms in exactly 12.00 grams of 12C.

3.2

1 mol = NA = 6.0221367 x 1023

Avogadro’s number (NA)

M = molar mass in g/mol

NA = Avogadro’s number

Molecular mass (or molecular weight) is the sum of

the atomic masses (in amu) in a molecule.

SO2

1S 32.07 amu

2O + 2 x 16.00 amu

SO2 64.07 amu

For any molecule

molecular mass in amu = molar mass in grams

1 molecule of SO2 weighs 64.07 amu

1 mole of SO2 weighs 64.07 g3.3

AVERAGE ATOMIC MASS

EX:- 3.1


Percent composition of an element in a compound =

n x molar mass of element

molar mass of compoundx 100%

n is the number of moles of the element in 1 mole

of the compound (assume you have 1 mole!).

%C =2 x (12.01 g)

46.07 gx 100% = 52.14%

%H =6 x (1.008 g)

46.07 gx 100% = 13.13%

%O =1 x (16.00 g)

46.07 gx 100% = 34.73%

52.14% + 13.13% + 34.73% = 100.0%

3.5

EX:-

Calculate the

%composition of

C,H and O in

C2H6O

Empirical FormulasDetermine the empirical formula of a

compound that has the following percent

composition by mass:

K 24.75%, Mn 34.77%, O 40.51% percent.

EMP.F

N= Wt./ATmass

OMnK

HOW CAN YOU FIND THE

MOLECULAR FORMULA FROM THE

EMPRICAL FORMULA

EX:- 3.1


Chapter 3 Mass Relationships in Chemical Reactions

___________________________________________________________________________

1. What is the mass, in grams, of one copper atom?

A. 1.055 10-22

g

B. 63.55 g

C. 1 amu

D. 1.66 10-24

g

E. 9.476 1021

g

2. Determine the number of moles of aluminum in 96.7 g of Al.

A. 0.279 mol

B. 3.58 mol

C. 7.43 mol

D. 4.21 mol

E. 6.02 1023

mol

3. Which of the following samples contains the greatest number of atoms?

A. 100 g of Pb

B. 2.0 mole of Ar

C. 0.1 mole of Fe

D. 5 g of He

E. 20 million O2 molecules


4. Formaldehyde has the formula CH2O. How many molecules are there in 0.11 g of formaldehyde?

A. 6.1 10-27

B. 3.7 10-3

C. 4

D. 2.2 1021

E. 6.6 1022

5. How many sulfur atoms are present in 25.6 g of Al2(S2O3)3?

A. 0.393

B. 6

C. 3.95 1022

D. 7.90 1022

E. 2.37 1023

6. The percent composition by mass of a compound is 76.0% C, 12.8% H, and 11.2% O. The molar mass of this

compound is 284.5 g/mol. What is the molecular formula of the compound?

A. C10H6O

B. C9H18O

C. C16H28O4

D. C20H12O2

E. C18H36O2


7. What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole

numbers?

___ Al4C3 + ___ H2O ___ Al(OH)3 + ___ CH4

A. 3

B. 4

C. 6

D. 12

E. 24

8. When 22.0 g NaCl and 21.0 g H2SO4 are mixed and react according to the equation below, which is the limiting

reagent?

2NaCl + H2SO4 Na2SO4 + 2HCl

A. NaCl

B. H2SO4

C. Na2SO4

D. HCl

E. No reagent is limiting.

9. How many grams of Cl2 can be prepared from the reaction of 16.0 g of MnO2 and 30.0 g of HCl according to the

following chemical equation?

MnO2 + 4HCl MnCl2 + Cl2 + 2H2O

A. 0.82 g

B. 5.8 g

C. 13.0 g

D. 14.6 g

E. 58.4 g


10. What is the theoretical yield of chromium that can be produced by the reaction of 40.0 g of Cr2O3 with 8.00 g of

aluminum according to the chemical equation below?

2Al + Cr2O3 Al2O3 + 2Cr

A. 7.7 g

B. 15.4 g

C. 27.3 g

D. 30.8 g

E. 49.9 g

Answer Key 1.A 2.B 3.B 4.D 5.E 6.E 7.D 8.A 9.C 10.B


CHAPTER 4 :-

EX:-

Dilution :- is the procedure for preparing a less concentrated solution from a more

concentrated solution. Mi Vi = MF VF

EX:-

How would you prepare 60.0 mL of 0.200 M HNO3 from a stock solution of 4.00 M

HNO3?

Solution Stoichiometry:- The concentration of a solution is the amount of solute present in a given

quantity of solvent or solution.

M = molarity =

moles of solute

liters of solution

What mass of KI is required to make 500. mL of a 2.80 M KI solution?

DILUTION

Add Solvent


Chapter 4 Reactions in Aqueous Solution

1. What mass of K2CO3 is needed to prepare 200. mL of a solution having a potassium ion concentration of 0.150 M?

A. 4.15 g

B. 10.4 g

C. 13.8 g

D. 2.07 g

E. 1.49 g

2. A 50.0 mL sample of 0.436 M NH4NO3 is diluted with water to a total volume of 250.0 mL. What is the ammonium

nitrate concentration in the resulting solution?

A. 21.8 M

B. 0.459 M

C. 2.18 10-2

M

D. 8.72 10-2

M

E. 0.109 M

3. How many milliliters would you need to prepare 60.0 mL of 0.200 M HNO3 from a stock solution of 4.00 M HNO3?

A. 60 mL

B. 240 mL

C. 24 mL

D. 1000 mL

E. 48 mL

Answer Key: 1. D 2. D 3. A


CHAPTER 2

Atomic number (Z) = number of protons in the nucleus.

Mass number (A) = number of protons + number of neutrons.

Isotopes are atoms of the same element (same number of

protons) but have different numbers of neutrons in their nuclei.

XAZ

C12

6 C13

6 C14

6

U23592 U238

92

Mass Number

Atomic NumberElement Symbol

2.3

Atomic number, Mass number and Isotopes

ALLOTROPS :- COMPOUND COMPOSED OF THE SAME ELEMENTS DUT THEY DIFFER IN THEIR

NATURE AND THEIR SHAPS AS ( GRAPHITE & DIAMOND ) ( O2 & O 3 )

COMPLETE THE TABLE :-

ELEMENT AT.# AT.MASS p e n


Rows or Periods

Gro

up

s or F

amilies

Alkali M

etals

Noble G

ases

Halogens

Alkaline E

arth Metals

2.4

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Periodic table


MOLECULES DEVIDED INTO :-

A diatomic molecule contains only two atoms

A polyatomic molecule contains more than two atoms

A molecule is an aggregate of two or more atoms in a definite arrangement

held together by covalent bonds.


An ion is an atom, or group of atoms, that has a net

positive or negative charge.

Cation: ion with a positive charge

• If a neutral atom loses one or more electrons

it becomes a cation.

Anion: ion with a negative charge

• If a neutral atom gains one or more electrons

it becomes an anion.

Na11 protons

11 electrons Na+ 11 protons

10 electrons

Cl17 protons

17 electrons Cl-17 protons

18 electrons

2.5

A monatomic ion contains only one atom.

Na+, Cl–, Ca2+, O2–, Al3+, N3–

A polyatomic ion contains more than one atom.

OH–, CN–, NH4+, NO3–


2.6

A molecular formula shows the exact number of

atoms of each element in a molecule of the

substance.

An empirical formula shows the simplest

whole-number ratio of the atoms in a substance.

H2OH2O

molecular empirical

C6H12O6 CH2O

O3 O

N2H4 NH2

2.6


ionic compounds consist of a combination of cations

and anions.

• the formula is always the same as the empirical formula

• the sum of the charges on the cation(s) and anion(s) in each

formula unit must equal zero

The ionic compound NaCl. Na+ to Cl– ratio = 1 to 1

2.6

Formula of Ionic Compounds

Al2O3

2.6

2 x +3 = +6 3 x –2 = –6

Al3+ O2–

CaBr2

1 x +2 = +2 2 x –1 = –2

Ca2+ Br –

Na2CO3

2 x +1 = +2 1 x –2 = –2

Na+ CO32–


PLANE OF NOMENCLATUR

Chemical Nomenclature

Ionic Compounds

• often a metal + nonmetal

BaCl2 barium chloride

K2O potassium oxide

Mg(OH)2 magnesium hydroxide

KNO3 potassium nitrate

2.7

Transition metal ionic compounds• Indicate the charge on the metal with Roman

numerals (the Stock naming system).

• Common names use the “ic” and “ous” endings.

FeCl2 2 Cl– = –2 so Fe is +2 iron(II) chloride

(ferrous chloride)

FeCl3 3 Cl– = –3 so Fe is +3 iron(III) chloride

(ferric chloride)

Cr2S3 3 S–2 = –6 so Cr is +3 chromium(III) sulfide

2.7


Molecular compounds

• Made of nonmetals or nonmetals + metalloids.

• Use common names for these:

H2O, NH3, CH4

• The element further left in periodic table is first.

• The element closest to bottom of group is first.

• If more than one compound can be formed from the same elements, use the prefixes to indicate the number of each kind of atom to specify the compound.

• The last element ends in “ide.”

2.7

HI hydrogen iodide

NF3 nitrogen trifluoride

SO2 sulfur dioxide

N2Cl4 dinitrogen tetrachloride

NO2 nitrogen dioxide

N2O dinitrogen monoxide

Molecular Compounds

2.7


COMMONE COMPOUND NAMES :-

H2O ==== WATER ( SEE YOUR TEXT BOOK )

ANSWERS OF SOME H.W.Q


CHAPTER 1

Examples:-

The SI unit of mass is

(a). The pound (b). The gram (c). The kilogram (d). The mole.


The SI prefixes giga and micro represent, respectively:

A. 10-9 and 10-6.

B. 106 and 10-3.

C. 103 and 10-3.

D. 109 and 10-6.

Which of the following is the smallest distance?

(a) 21 m → 21m

(b) 2.1 x 102 cm → 2.1m

(c) 21 mm → 0.021 m

(d) 2.1 x 104 pm → 2.1 x 10-8 m

The diameter of an atom is approximately 1 10-7 mm. What is this diameter

when expressed in nanometers?

A. 1 10-18 nm

B. 1 10-15 nm

C. 1 10-9 nm

D. 1 10-1 nm

Which of these quantities represents the largest mass?

A. 2.0 102 mg

B. 0.0010 kg

C. 1.0 105 g

D. 2.0 102 cg


Put all of them in the same unit

A) 0.2 g

B)1 g

C) 0.1 g

D) 2 g

Mass is the measure of the amount of matter in an object.

SI unit of mass is the kilogram (kg)

1 kg = 1000 g = 1 x 103 g

Weight is the measurement of the pull of gravity on an object.

SI derived units

are defined in terms of the seven base quantities via a system of quantity

equations.

The SI derived units for these derived quantities are obtained from these

equations and the seven SI base units. For example

Area = width x length

Unit of width = m

Unit of length = m

Unit of Area = m× m = m2


Volume –

Volume = width × length × hieghst = m × m × m = m3

SI derived unit for volume is cubic meter (m3)

Common unit of volume is liter (L) and milliliter (ml)

The relation ship between liter (L) and ml (1L= 1000mL)

The relation ship between liter (L) and metric system

1 L = 1 dm3

The relation ship between milliliter (ml) and metric system

1 mL = 1 cm3

Density :-

is defined as the amount of matter in a given amount of space.

d = m/V

SI derived unit for density is kg/m3

1 g/cm3 = 1 g/mL = 1000 kg/m3

EX : -

A piece of Gold metal has a volume of 15.6 cm3, with a mass of 301 g What is its

density

301 g/ 15.6 cm3

= 19.3 g/ cm3


Temperature Scales

• Fahrenheit °F →°F = [ (9/5) × °C] + 32

• Celsius °C → °C = (5/9) (°F - 32)

• Kelvin ° K → ° K = °C + 273.15

EX:-

• Convert 224 0C to degrees Fahrenheit?

• °F = (9 0F /5 0C) × °C + 32

• [°F = (9 0F /5 0C) × 224 °C] + 32 0C = 435 0F

• Convert -452 0F to degrees Celsius.

• °C = (5 0C /9 0F) (°F - 32 0F)

• °C = (5 0C /9 0F) (-452 °F - 32 0F) = -269 0C

• Convert -38.9 0C to degrees Kelvin..

• ° K = [-38.9 °C + 273.15 °C ] × 1 K/ 1 0C = 234.3 K

• Ammonia boils at -33.4C. What temperature is this in F?

• A. -60.1F B. -92.1F

• C. -28.1F D. +13.5F

مراجعه كيمياء 110 دوري الاول

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