Introduction to chemistry Flashcards

Question

Deci-

Answer 1

1/10 x basic unit (10^-1)

Answer 2

1/100 x basic unit (10^-2)

Answer 3

1/1000 x basic unit (10^-3)

Answer 4

1/1,000,000 x basic unit (10^-6)

Answer 5

1/1,000,000,000 x basic unit (10^-9)

Answer 6

King Henry Died Unusually Drinking Chocolate Milk * Kilo (1000 or 103) * Hecto (100 or 102) * Deca (10 or 101) * Unit (1 unit) * Deci (1/10 or 10-1) * Centi (1/100 or 10-2) * Milli (1/1000 or 10-3)

Answer 7

Fo = 9/5(C) + 32

Answer 8

Co = 5/9(F - 32)

Answer 9

K = C + 273

Answer 10

C = K - 273

Answer 11

* 1 cal = 4.184 J * 1kcal = 4184 J

Answer 12

A number to the zero power is always 1.

Answer 13

Zeros not preceded by nonzero numbers are not significant figures. These zeros are sometimes called leading zeros.
Zeros located between nonzero numbers are significant figures. These zeros are sometimes called buried or confined zeros.
Zeros located at the end of a number are significant figures if there is a decimal point present in the number. These zeros are sometimes called trailing zeros. If not decimal point is present, trailing zeros are not significant.

Answer 14

* The answer obtained by multiplication or division must contain the same number of significant figures as the quantity with the fewest significant figures used in the calculation * The answer obtained by addition or subtraction must contain the same number of places to the right of the decimal as the quantity in the calculation with the fewest number of places to the right of the decimal.

Answer 15

Density = Mass/Volume
Mass = Density*Volume
Volume = Mass/Density

Answer 16

Isotopes are atoms that have the same atomic number but different mass numbers - that is, they are atoms of the same element that contain different numbers of neutrons in their nuclei

The top number is the mass number and the bottom is the atomic number. Also, remember that you can use the elemental name followed by the mass number (e.g., hydrogen-1, hydrogen-2, and hydrogen-3)

Answer 17

Molar Mass: The mass of one mole of a substance (expressed in grams) is numerically equal to the substance’s atomic or molecular mass (expressed in amu). For example, the molar mass of Carbon-12 is exactly 12 grams per mole, and the molar mass of water (H₂O) is ~ 18 grams per mole (since the molecular weight of H₂O is ~ 18 amu.

Ex: Molar Mass of Sulfur (32.06 grams/1 mole) or (1 mole/32.06 grams)

Ex: Concentration of solution: 0.55 molar sodium chloride solution = 0.55 M NaCl (0.55 mole NaCl/1 L solution) or (1 L solution/0.55 mole NaCL)

Answer 18

6.022 x 10²³

Answer 19

S-subshell: has 1 orbital -- can fit 2 electrons

P-subshell: has 3 orbitals -- can fit 6 electrons

D-subshell: has 5 orbitals -- can fit 10 electrons

F-subshell: has 7 orbitals -- can fit 14 electrons

Answer 20

Only 2 electrons can fit in each orbital. For example, a 4p orbital can only have 2 electrons.

Answer 21

Hund's rule states that electrons will not join other electrons in an orbital if an empty orbital of the same energy is available for occupancy

Answer 22

Pauli exclusion principle states that only electrons spinning in opposite directions can simultaneously occupy the same orbital

Answer 23

Noble gas configurations – an electronic configuration in which the last eight electrons occupy and fill the s and p subshells (the shell is full) of the highest-occupied shell

Answer 24

Distinguishing Electron is the last and highest-energy electron found in an element

Answer 25

Noble gases make up the group found on the extreme right of the periodic table – they are all gases at room temperature and are unreactive with most other substances
Representative elements are those in which the distinguishing electron is found in an s or a p subshell
Transition elements are those in which the distinguishing electron is found in the d subshell
Inner-transition elements are those in which the distinguishing electron is found in the f subshell

Elements can also be classified into metals, nonmetals, and metalloids

Answer 26

Metals – have the following properties

High thermal conductivity – they transmit heat readily
High electrical conductivity – they transmit electricity readily
Ductility – they can be drawn into wires
Malleability – they can be hammered into thin sheets
Luster – they have a characteristic “metallic” appearance

Nonmetals – generally have chemical and physical properties opposite to those of metals – under normal conditions, they often occur as brittle, powdery solids or as gases

Metalloids – such as boron and silicon, have properties somewhat between those of metals and nonmetals, and they often exhibit some of the characteristic properties of each type

Answer 27

Elements get more metal as you move to the left and down

Answer 28

Size of elements: The sizes tend to increase from top to bottom of each group, and then decreases from left to right for each period
Ionization energy: (Opposite of size) Increases as we move to the right and decreases as we move down
Metallic: Elements become less metallic as we move from left to right, and more metallic as we move from top to bottom (so most metallic are in bottom left)

Answer 29

Ionization energy is the energy required to remove an outermost electron from an atom of the element in the gaseous state

Answer 30

Octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell -- it is also a rule for predicting behavior in reacting atoms – it says that atoms will gain or lose sufficient energy electrons to achieve an outer electron arrangement identical to that of a noble gas – 8 electrons

Answer 31

Lewis Structures – representation of an atom or ion in which the elemental symbol represents the atomic nucleus and all but the valence-shell electrons – the valence-shell electrons are represented by dots arranged around the elemental symbol

You can do this by writing out the electron configuration or the simpler alternative for representative elements is to refer to the periodic table and note that the number of valence-shell electrons in the atoms of an element is the same number as the group in the periodic table

Answer 32

Simple ions – an atom that has acquired a net positive or negative charge by losing or gaining electrons
And the attractive force between oppositely charged atoms constitutes an ionic bond – the attractive forces that holds togethers ions of opposite charge
As a general rule, metals lose electrons and nonmetals gain electrons during ionic bond formation
The number of electrons lost or gained by a single atom rarely exceeds three

Answer 33

Ionic compounds -- chemical compound composed of ions held together by electrostatic forces termed ionic bonding – no atom can lose electrons unless another atom is available to accept them (e.g., FeCl₂)
Always write metal first and non-metal second and just add -ide to the nonmetal
Never need to write out the charges (just write Calcium Chloride), but you need to name the charge with an inner transition metal, such as Iron (II) Chloride – FeCl₂ -- because you need to specify the charge
The ratio is determined by the charges on the ions, which are determined by the number of electrons transferred

Answer 34

A chemical bond formed by sharing a pair of electrons is a covalent bond – the attractive force that results between two atoms that are both attracted to a shared pair of electrons (tend to be non-metals to non-metals)

Atoms want to have 8 valence electrons (or more stable shells) and will share electrons with other atoms – unlike ionic bonds where one is willing to give up electrons and the other is willing to accept, covalent bonds tends to happen between atoms that don’t want to give up electrons because they would then be left unstable, so they share electrons instead

Answer 35

Combination of ionic and covalent bonding is found in compounds that contain polyatomic ions – these are ions that are covalently bonded groups of atoms that carry a net electrical charge

Common polyatomic ions are negatively charged (except for NH₄⁺)

Answer 36

VSEPR (Valence-shell electron-pair repulsion theory) – electron pairs in the valence shell of an atom are repelled by other electron pairs and get as far away from one another as possible

When the VSEPR theory is applied to the valence-shell electrons of a central atom, the shape of the molecule or ion containing the atoms can be predicted – two rules are followed:

All valence-shell electron pairs around the central atom are counted equally, regardless of whether they are bonding or nonbonding pairs
Double or triple bonds between atoms are treated like a single pair of electrons when predicting shapes

The electron pairs around a central atom will orient themselves in a space to get as far away from one another as possible

Thus, two pairs will be oriented with one pair on each opposite side of the central atom
Three pairs will form a triangle around the central atom
Four pairs will be located at the corners of a regular tetrahedron with the central atom in the center

Answer 37

In ionic bonds, two atoms join because their is a transfer in electrons. One atom will give up electrons while the other accepts them. Both of them become charged atoms, or ions, and the electrostatic force pulls them together (positive + negative). Thus, they are formed through the transfer of electrons.

Covalent bonds are when atoms share molecules.

Answer 38

Nonpolar Covalent -- there is equal sharing of electrons (the change in electronegativity is 0 -- both have the same electronegativity

Polar Covalent -- there is an unequal sharing of electrons (the change in electronegativity is between 0 and 2.1)

Answer 39

Molecules where one side is partially positive and the other side is partially negative, it is a polar bond. The electrons are unequally distributed. The more electronegative atom requires a partial negative charge and the less electronegative atom has a partial positive charge.

Answer 40

Electronegatively increases from left to right and decreases from top to bottom.

Answer 41

Give the name of the less electronegative element first (the element given first in the formula)
Give the stem of the name of the more electronegative element next and add the suffix -ide
Indicate the number of each type of atom in the molecule by means of the Greek prefixes (see table below)

Number	Prefix
1	mono-
2	di-
3	tri-
4	tetra-
5	penta-
6	hexa-
7	hepta-
8	octa-
9	nona-
10	deca-

Answer 42

Sulfate: SO₄^2-
Phosphate: PO₄^3-

Answer 43

Covalent bonds (strongest): Nonmetal -- Nonmetal
Metallic bonds (next strongest): Metal -- Metal
Ionic bonds (weakest): Nonmetal -- Nonmetal

Answer 44

Decomposition reactions are when a single substance is broken down to form two or more simpler substances (AB --> A + B) -- typically requires a catalyst

Combination reactions or synthesis reactions and is when two or more substances react to form a single substance (A + B --> C)

Single-replacement reactions or substitution reactions, are always redox reactions and take place when one element reacts with a compound and displaces another element from the compound (A + BX --> B + AX)

Double-replacement reactions, also called metathesis reactions, are never redox reactions and is a chemical reaction in which two compounds react and exchange partners to form two new compounds (AX + BY --> BX + AY)

Answer 45

OIL RIG

Oxidation is losing electrons and are reducing agents
Reduction is gaining electrons and are oxidizing agents

In those atoms that are being reduced, they DECREASE in oxidation number

Answer 46

Element by itself is 0 [Eg, Cl₂, Na, S₆, are always 0]
Monoatomic ion = the ion charge [e.g., K+ (+1), N^3- (-3), Mg²⁺(+2)]
Group IA – Always +1 [e.g., KCl (K = +1)]
Group IIA – Always +2
Halogens (7A) – usually -1, but positive with oxygen
Hydrogen – is +1 with nonmetals and -1 with metals
Oxygen – usually -2 but is -1 in peroxide (H₂O₂)
Sum of ON’s for a neutral compound = 0
Sum of ONs for a polyatomic ion = ion charge

Answer 47

First, you must convert from grams to moles, moles to moles, and then moles to grams

1. Calculate the amount of product that can be formed by the initial amount of each reactant
1.A. The reactant that gives the smaller amount of product is the limiting reactant
1.B. The smaller amount of product is the amount that will be formed when the limiting reactant is used up

2. Calculate the amount of the non-limiting reactant that is needed to use up the limiting reactant

3. Subtract the amount of non-limiting reactant needed to use up the limiting reactant from the original amount of non-limiting reactants -- the difference is the excess amount of the non-limiting reactant

Answer 48

Reaction yield refers to the amount of product obtained in a chemical reaction.

It is calculated by dividing the actual yield by the theoretical yield x 100.

% yield = actual yield / theoretical yield x 100

Answer 49

Y a-t-il la climatisation dans la pièce ?

Answer 50

No. It must be different because its melting point is different from that of aspirin.

Answer 51

The aspirin molecules must be larger because the atoms of the aspirin were divided between the molecules of the new solid and the molecules of the evolved gas.

Answer 52

Heteroatomic, because the aspirin changed into two different substances, molecules of aspirin must contain at least two different kinds of atoms.

Answer 53

homogenous

Answer 54

homogenous

Answer 55

heterogeneous

Answer 56

heterogenous