Chapter 2: Molecules and Solutions Flashcards

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1
Q

What are atoms or elements?

A
  • smallest unit of matter
  • parts of molecules
  • shown on the periodic table of elements
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2
Q

What are molecules and give an ex

A

they are made up of two or more atoms bonded together. ex: O2

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3
Q

What are compounds and give an example

A

a compound consists of two or more DIFFERENT elements that can be separated into simpler substances by chemical reactions. ex: NaCl

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4
Q

What does the bonding of elements rely on?

A

the capability of each to gain or lose electrons

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5
Q

What is an ion?

A

an atom that has become electrically charged by losing or gaining one or more electrons

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6
Q

What do atoms want?

A

The same electronic configuration as noble gases for stability (following the octet rule)

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7
Q

What does the valence electrons refer to?

A

The electrons on the outermost shell

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8
Q

What do the valence/oxidation number refer to?

A

the number of electrons lost or gained to achieve a noble gas configuration.

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9
Q

What is a polyatomic ion and give an example.

A

an ion composed of two or more atoms acting as a single unit in chemistry.
ex: NH4^+1
(found on the back side of the periodic table)

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10
Q

What are chemical bonds?

A

union of two or more atoms through the transfer or sharing of one or more electrons

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11
Q

What do atoms usually try to do?

A

they try to fill their valence shell (octet rule)

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12
Q

What are ionic bonds?

A
  • formed between a metal or a non-metal
  • 1 or more electrons are transferred from one atom (usually metal) t oanother atom (non- metal)
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13
Q

What are covalent bonds formed between

A

two non-metals where electrons are shared

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14
Q

What are diatomic molecules?

A

molecules composed only of two atoms of same chemcial elements.

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15
Q

Describe the three bonds of Diatomic Molecules.

A

single bond shares one pair of electrons (H2)
double bond shares two pairs of electrons (O2)
triple bond shares three pairs of electrons (N2)

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16
Q

What are ions

A

In a single atom, chargé results from having either more electrons or less electrons than protons.
More electrons than protons= negative charge
Less electrons than protons= positive charge

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17
Q

Describe the 5 step cross over rule

A
  1. Write ions side by side (metals first
  2. Write the ion charge
  3. Cross-over to determine number of each element
  4. The number from the charge of 1st ion gives the number of the 2nd ion and vice versa.
  5. Simplify and/or drop any “1”
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18
Q

Give an example of cross over

A

Step 1: Ca^2+ O^2-
Step 2: Ca^2 O^2
Step 3: drop the twos
Step 4: CaO

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19
Q

How does polyatomic ion act when balancing charges in compounds. Give an example

A

Acts as a single unit with a charge
Ex: NH4^1+. PO4^3-
(NH4)3PO4

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20
Q

What does nomenclature mean

A

Naming things

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21
Q

What are noble gases

A

Monatomic

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22
Q

What are all gaseous reacting elements

A

Diatomic

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23
Q

What are halogens

A

Diatomic

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24
Q

How do u nomenclature covalent.

A

-it is only two non-metals
-name each element (start with the positive one)
-end the last element in “ide”
-add prefixes to show more than 1 atom

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25
Q

What are the prefixes

A

Mono: 1
Di: 2
Tri: 3
Tetra: 4
Penta: 5
Hexa: 6
Hepta: 7
Octa: 8
Nona: 9
Deca: 10

26
Q

What is nomenclature ionic

A

-metal and nonmetal
-name each element
-positive ion first then negative ion
-add “ide” to the second ion
-no prefixes

27
Q

What is nomenclature polyatomic ions

A

-metal (positive) first
-then polyatomic (mostly negative) with its normal name

28
Q

Give an example of a covalent nomenclature name

A

Pentoxide

29
Q

Give an example of ionic nomenclature names

A

Calcium chloride

30
Q

Give an example of polyatomic ions nomenclature names

A

Aluminium hydroxide

31
Q

What is a solution

A

a homogeneous mixture (parts that can<t be distinguished)

32
Q

What is a solute

A

the component of the solution that is dissolved (usually in lesser quantity)

33
Q

What is a solvent

A

the component of the solution during the dissolving (usually in greater quantity)

34
Q

What is an aqueous solution

A

a solution in which the solvent is water. HCl (Aq)

35
Q

What is solubility

A

the maximum amount of solute that can be dissolved in a certain volume of solvent.

36
Q

what is concentration

A

the amount of solute in a given amount of solution

37
Q

What is the formula for concentration

A

c=m/v

38
Q

what is the formular for dilution

A

c1 x v1 = c2 x v2

39
Q

What is morality /molar concentration

A

The number of moles of solute in a given amount of solution

40
Q

What is the formulae for morality

A

M= n/v

41
Q

What is the formula for molar dilution

A

M1 x V1 = M2 x V2

42
Q

Give an example of ppm

A

3.2g/L x 3200mg/1L=3200ppm

43
Q

What is an electrolyte

A

A substance that allows an electric current to flow through the solution

44
Q

What is electrolytic dissociation

A

The separation of a dissolved compound into 2 ions of opposite charges

45
Q

Give an example of electrolytic dissociation equation

A

Na+1 (aq) + Cl-1 (aq)

46
Q

What is the electrolytic conductivity of a solution

A

It’s a measure of its ability to allow an electric current to flow through it during to the ions carrying the change

47
Q

what does the strength of an electrolyte depend on

A

on its degree of dissociation:
- some dissociate 100% into ions so they carry electricity easily
- some dissociate into few ions so they carry electricity weakly
- some do not dissociate at all so they do not carry electricity at all.

48
Q

what is an acid

A

a substance that gives h+ ions in water

49
Q

chemical formular for acid usually starts with

A

usually starts with H

50
Q

what is the pH of an acid

A

[0,7[ litmus paper turns red

51
Q

what is the exception of acids

A

CH3COOH

52
Q

what is a base

A

substance that gives OH-1 ions in water

53
Q

what does the base formula usually end with

A

OH (generally combinatin of a metal and OH)

54
Q

what is the pH of a base

A

]7.14] litmus paper turns blue

55
Q

what is the exception for a base

A

ammonia

56
Q

what is a salt

A

a substance produced from the bonding of a
metallic ion and a nonmetallic ion.

57
Q

explain the formula of a salt

A

They don’t start with H or end with OH (Always a
combination of Metal and Non-Metal)

58
Q

explain the pH scale of a salt

A

They can be acidic, basic or neutral

59
Q

explain what neutralization is

A

acids and bases neutralize each other and the product is always neutral.

60
Q

give the formula for neturalization

A

Acid + Base = Salt + Water

61
Q

what is an indicator used for

A

used to detect the presence of an acid or a base. some reveal the exact pH