Midterm Exam (Chapters 1-7)

Question 1

Quantitative observations

Answer 1

Measurements (consist of a number and a unit)

Question 2

Qualitative observations

Answer 2

Visual, sensual observations that do not involve numbers

Question 3

Metric prefixes

Answer 3

10^6 = Mega (M)
10^3 = Kilo (k)
10^2 = Hecto (h)
10^1 = Deka (da)
10^0 = BASE UNIT
10^-1 = Deci (d)
10^-2 = Centi (c)
10^-3 = Milli (m)
10^-6 = Micro (u)
10^-9 = Nano (n)

Question 4

Uncertainty in a measurement

Answer 4

We have to estimate the last digit of measurements due to the limits of measuring devices. Uncertainty depends on the precision of the measuring device.

Question 5

Converting from Celsius to Fahrenheit

Answer 5

TºF = 1.8TºC + 32

Question 6

Density formula

Answer 6

d = m/V

Question 7

Density of water

Answer 7

1 g/mL

Question 8

Rule for adding/subtracting significant measurements

Answer 8

Round to the lowest number of decimal places

Question 9

Rule for multiplying/dividing significant measurements

Answer 9

Round to the lowest number of significant figures

Question 10

Separation techniques that can be used to separate mixtures

Answer 10

Distillation - volatility
Filtration - size/state of manner
Chromatography - polarity
Centrifugation - density (homogeneous mixtures)

Question 11

Law of multiple proportions

Answer 11

When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 g of the first element can always be reduced to small whole numbers.

Question 12

Nuclide symbol

Answer 12

A = mass number (total number of protons and neutrons)
Z = atomic number (number of protons)
X = element symbol

Question 13

Isotope

Answer 13

Atoms with the same number of protons but different numbers of neutrons

Question 14

Cation

Answer 14

Positive ion formed by losing an electron

Question 15

Anion

Answer 15

Negative ion formed by gaining an electron

Question 16

Chemical formula

Answer 16

Illustrates molecules, where the element symbols are used to indicate the types of atoms present, and subscripts are used to indicate the relative numbers of atoms

Question 17

General properties of metals

Answer 17

• Efficient condition of heat and electricity
• Malleability, ductility
• (Often) lustrous appearance
• Tend to use electrons to form positive ions (cations)

Question 18

Limiting reactant

Answer 18

The reactant that is completely consumed when a reaction is run to completion

Question 19

Strong acids

Answer 19

HCl
HF
HBr
HNO3
H2SO4
HClO4

Question 20

Strong bases

Answer 20

LiOH
NaOH
KOH
Ca(OH)2
Sr(OH)2
Ba(OH)2

Question 21

Molarity

Answer 21

Moles of solute per volume of solution in liters

Question 22

Solubility rules

Answer 22

SOLUBLE:
NO3^-1, Group IA Elements, NH4^+1 (NO EXCEPTIONS)
Cl^-1, Br^-1, I^-1 (EXCEPT Ag^+1, Pb^+2, Hg2^+2)
SO4^-2 (EXCEPT Ba^+2, Pb^+2, Hg2^+2, Ca^+2)

INSOLUBLE:
OH^-1 (EXCEPT Na^+1, K^+1, Ba^+2, Sr^+2, Ca^+2)
S^-2, CO3^-2, CrO4^-2, PO4^-3 (EXCEPT Group IA, NH4^+1)

Question 23

Four types of oxidation-reduction reactions

Answer 23

1. Synthesis
2. Decomposition
3. Combustion
4. Single-replacement

Question 24

Oxidation state rules

Answer 24

1. Atom in an element = 0
2. Monatomic ion = Charge of the ion
3. Oxygen = -2 in covalent compounds (-1 in peroxides)
4. Hydrogen = +1
5. Fluorine = -1
6. Sum of oxidation states in compounds = 0
7. Sum of oxidation states in polyatomic ions = Charge of the ion

Question 25

Gases have ________ densities.

Answer 25

Low

Question 26

Gas laws

Answer 26

Boyle: Indirect relationship between pressure and volume Charles: Direct relationship between temperature and volume Avogadro: Direct relationship between number of moles and volume

Question 27

Ideal gas

Answer 27

Exactly follows the ideal gas law (PV=nRT), has particles so small compared with the distances between them that the volume of the individual particles can be assumed to be negligible (zero). The particles are in constant motion, so the collisions of the particles with the walls of the container are the cause of the pressure exerted by the gas. The particles are assumed to exert no forces on each other, so they are assumed to neither attract nor repel each other. The average kinetic energy of a collection of gas particles is assumed to be directly proportional to the Kelvin temperature.

Question 28

When do gases not behave ideally?

Answer 28

When temperatures are low and pressures are high. Real gases have high gas particle concentrations, attractive forces, and actual pressures are lower than ideal pressures.

Question 29

STP

Answer 29

Standard temperature and pressure (273 K and 1 atm)

Question 30

Rate of effusion

Answer 30

The speed at which a gas is transferred into an evacuated chamber through a tiny orifice Rate of effusion for gas 1/rate of effusion for gas 2 = √M2/√M1 (Inverse ration of the square roots of the molar masses)

Question 31

What influences the intermolecular attractions among gas molecules?

Answer 31

A high concentration of gas molecules means that it is more likely that a pair of gas particles will be close enough to attract each other. When gas particles come close together, attractive forces occur, which cause the particles to hit the wall very slightly less often than they would in the absence of these interactions. The amount of moles of gas particles per liter (n/V) affects that.

Question 32

BIG WHOPPER

Answer 32

1 atm = 760 torr = 760 mmHg = 101.325 kPa = 101325 Pa = 14.69 psi = 29.92 inHg

Question 33

Heat (q)

Answer 33

``` + = A quantity of energy flows into the system via heat (ENDOTHERMIC) - = A quantity of energy flows out of the system via heat (EXOTHERMIC) ```

Question 34

Work (w)

Answer 34

``` + = Surroundings do work on the system (energy flows into the system) - = System does work on the surroundings (energy flows out of the system) ```

Question 35

Specific heat capacity

Answer 35

The energy required to raise the temperature of one gram of a substance by one degree Celsius

Question 36

Heat capacity

Answer 36

Heat absorbed per increase in temperature

Question 37

Standard enthalpy of formation

Answer 37

The change in enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states

Question 38

Hess's Law

Answer 38

In going from a particular set of reactants to a particular set of products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.

Question 39

Types of radiation

Answer 39

Gamma rays, x-rays, ultraviolet, VIBGYOR, infrared, microwaves, radio waves

Question 40

Atomic orbital

Answer 40

A specific wave function for an electron in an atom. The square of this function gives the probability distribution for the electron.

Question 41

Principal energy level

Answer 41

Describes the size and energy of an orbital

Question 42

Sublevel

Answer 42

Describes the shape of atomic orbitals | e.g.: s, p, d, f

Question 43

Ionization energy

Answer 43

The energy required to remove an electron from a gaseous atom or ion

Question 44

Electron affinity

Answer 44

The energy change associated with the addition of an electron to a gaseous atom

Question 45

Periodic trends

Answer 45

Ionization energy: First ionization energy increases as we go across a period from left to right. The first ionization energy decreases in going down a group. Atomic radius: Decreases going across a period. Increases going down a group. Electron affinity: When we go down a group, electron affinity becomes more positive (less energy released)

Question 46

Energy levels available to the electron in the hydrogen atom

Answer 46

``` E = -2.178 x 10^-18 J (Z^2/n^2) Z = nuclear charge (1) n = energy level (integer) ```

Question 47

Energy of a photon

Answer 47

Ephoton = hc/λ = hν

Question 48

Mass of a light particle

Answer 48

m = h/λv v = velocity

Question 49

Formula for the speed of light

Answer 49

λv = c Speed of light = 2.9979 x 10^8 m/s