midterm (kms) Flashcards
(104 cards)
1
Q
if a small fire breaks out on your bench you should
A
either invert a beaker over it to deprive it of O2 or call for the fire blanket
2
Q
wash (“squirt”) bottles should be filled ‘only’ with
A
deionized water
3
Q
you can’t use a beaker to
A
measure the exact amount of something
4
Q
1 cubed cm of lead has a mass of 11.34 g. This statement represents lead’s
A
density
5
Q
How many millimeters in .62 cm
A
6.2 mm
6
Q
convert 300 decaliters to centiliters
A
300,000 cL
7
Q
find the sum: 2.17+4.32+401.278+21.821
A
429.59
8
Q
u measured the length of an index card to be 7.3 cm. it’s supposed to be 7.5 cm. what’s the percent error?
A
2.7%
9
Q
When doing the calculation 25.1 x 453.2, how should you report your answer?
A
11,400
10
Q
round 90,221 to 4 significant digits
A
90,220
11
Q
what is 24.57+5.678+5.3?
A
35.5
12
Q
what’s 0.0012/5.9?
A
0.00020
13
Q
what’s 59.34 x 5?
A
300
14
Q
what’s 8.895-6.22?
A
2.68
15
Q
what’s the specific heat of a substance if 1560 cal is needed to raise the temp of a 312 g sample by 15 degrees Celsius/
A
0.33 cal/g C
16
Q
how many kilojoules are equal to 3254 calories?
A
13.61 kJ
17
Q
how many kilocalories of heat are required to raise the temperature of 225 g of Al (C of Al is 0.21 cal/g C) from 20 Celsius to 100 Celsius?
A
3.8 cal
18
Q
the amount of heat transferred from an object depends on all the following except:
a. the specific heat of the object
b. the change in temperature the object undergoes
c. the initial temperature of the object
d. the mass of the object
A
c
19
Q
is a calorie smaller than, larger than, or the same size as a joule?
A
larger than
20
Q
in an exothermic reaction, the energy stored in the chemical bonds of the reactants is
A
greater than the energy stored in the bonds of the product
21
Q
Boyle’s law states that
A
the volume of a gas varies inversely with pressure
22
Q
Charles’s law states that
A
the volume of a gas is directly proportional to its temperature in Kelvin
23
Q
If a sealed syringe is plunged into cold water, in which direction will the syringe piston slide?
A
in
24
Q
A sample of gas occupies 17 mL at -112 C. What volume does the sample occupy at 70 C?
A
36 mL-remember to convert to Kelvin!
25
At high pressures, how does the volume of "real gas" particles compare with the volume of "idea gas" particles under the same conditions?
it's much greater
26
gases are characterized by
no intermolecular interactions present particles
27
Which statement about atmospheric pressure is false?
1. as air becomes thinner, its density decreases
2. air actually has weight
3. with an increase in altitude, atmospheric pressure increases as well
4. the colder the air, the lower the atmospheric pressure
3
28
pure substances made up of more than 1 element are called _______
compounds
29
boiling water is classified as a(n) (exothermic/endothermic/neither) process
endothermic
30
in order to separate a mixture of salt and water, you can use
distillation
31
to break bonds, you need to ____ energy
add
32
density is a (qualitative/quantitative), (intensive/extensive) property
quantitative, intensive
33
btw when a question like "how long did a substance take to freeze" is asked it's asking how long the FREEZING process took. it's just isolating the freezing. it's not from te beginning of the curve
34
what element in the fourth period has 2 valence electrons?
Ca (calcium)
35
chemical bonds can be produced by any of the following processes except:
a. splitting electrons
b. gaining electron
c. losing electrons
d. sharing electrons
a
36
look for notes regarding how to tell the melting point/polarity/etc of a compound from its name
37
What's the symbol for the ion formed when zinc (Zn) loses its valence electrons?
Zn^-2
38
Aluminum hydroxide has the formula:
Al (OH)3
39
the chemical name of IBr is
iodine monobromide
40
An unknown element is found to have 3 naturally occurring isotopes with atomic masses and relative abundances of
41 (1%) 39 (2%) 40 (97%)
Which of the following is the unknown element?
a. Ar
b. K
c. Cl
d. Ca
Ar (a)
41
How many grams are in 5.57x10^23 atoms of copper?
58.8g
42
find the empirical formula of a compound with a percentage composition of 52.3% C, 13% H, and 34.7% O
a. CH3O
b. C2H6O
c. C2H6O2
d. C4H12O2
b
43
What characterizes solids?
- very high density
- particles vibrate around a fixed position relative to each other
- particles are tightly packed together
- completely incompressible for most applications (unless you get a hydraulic press)
- definite shape and volume
- strong particle attraction
- forms crystals when particles are locked into a geometric shape
- very low kinetic energy
- has mass
44
what characterizes liquids?
- weak particle attraction
- particles are relatively close together
- virtually incompressible for most applications
- intermolecular forces cause surface tension and capillary action
- particles slide past each other
- definite volume, no definite shape
- low to high kinetic energy
- can flow
- has mass
45
what characterizes gases?
-condense
-highly compressible
-virtually no particle attraction
-mostly empty space
-particles bounce off of each other
-very compressible
-expands by diffusion to completely fill chamber
-particles are very far apart
-no definite shape or volume
-very low density
-very high kinetic energy
-has mass
-can flow
-ideal behavior at low pressure, high temperature
46
endothermic
when system gets warmer and surroundings get colder (ex. boiling)
47
exothermic
when systems get colder and surroundings get warmer (ex. freezing)
48
general lab rules
- don't pipette by mouth
- don't assume that any unknown chemical is safe
- don't step over danger lasers
- don't cover up first aid
49
When should the fire blanket be used?
for fires on you/bench
50
kinetic molecular theory (KMT)
- particles of matter are in constant, random motion
- avg speed of particles increases w temp
- macroscopic properties of matter dependent on motion at particle level
- interactions among particles, particularly in liquids and solids, determine physical properties of matter
51
What is the difference between temperature and heat?
- temperature: a **measure** of the average kinetic energy of the particles (kinetic energy has to do with speed, so temperature only depends on speed)
- heat: a type of **energy** that can be transferred between 2 substances which have different temperatures (heat flows from warmer objects to cooler objects until thermal equilibrium is reached)
52
calorimetry
the measurement of heat change for chemical and physical processes
53
intensive property
a characteristic of a substance that depends on the type of matter present (ex. density, color, specific heat, capacity, melting point, boiling point)
54
thermal equilibrium
when energy flow between 2 substances stops because their temperatures are equal
55
difference between potential and kinetic energy
potential (ex. chemical, nuclear, mechanical) is stored energy while kinetic (ex. heat, light, sound) involves motion
56
What does potential energy do in a heating curve?
it decreases
57
What's the equation for pressure?
force/area
58
kinetic molecular theory of gases (KMT)
- the volume of all the molecules of gas is negligible compared to the total volume of the container that holds the gas
- gases consist of big numbers of molecules/atoms that are in continuous, straight line motion
- no present intermolecular forces in between gases
- energy is transferred between molecules during collisions. the collisions are perfectly elastic, meaning the molecule's total average kinetic energy stays the same
- increase in temp increases avg kinetic energy (this is true for any matter but whateva)
59
When do gases start behaving less ideal?
as they approach liquid phase (low temp, high pressure)
60
What are the pressure conversions?
1atm=760mmHg=760torr=101.3kPa=101,300Pa=14.7psi (pounds per square inch)
61
filtration
separating **heterogeneous** mixtures of solids and liquids based on differences in size or solubility
62
decanting
separates a liquid from atop a solid in a heterogeneous mixture
63
centrifugation
separates heterogeneous mixtures based on density differences by spinning a rotor around at several thousand times the force of gravity. denser substance settles to bottom
64
evaporation/distillation
- separates homogenous mixtures based on differences in boiling points
- when a solution is heated, the pure substance with the lower boiling point vaporizes first, leaving the other pure substance(s) behind
65
extensive
extensive properties depend on amount of matter (ex. volume, mass, energy)
66
what's the difference between physical and chemical properties?
**physical**
- can be observed/measured without changing the identity of the substance
- physical properties describe the substance itself, mainly by using your 5 senses
- classified as qualitative/quantitative and intensive/extensive
- ex. color, odor, taste, hardness, density, texture, viscosity, state of matter, solubility, malleability, ductility, tensile strength, composition, specific heat, size, volume, surface tension, pH, magnetic, mass, length, width, height, weight, luster, color, shape, temperature, conductivity
**chemical**
- properties that can be observed/measured during/after a chemical change
- describes how the substance interacts with other substances to produce a new substance
- ex. combustibility, corrosive, oxidizer, reducer, tarnishes, reactivity, rotting, spoiling, decomposing, degrading, flammability, rusting
67
solution
- mixture with uniform composition
- no distinct parts or layers
- no Tyndall effect, filtering out, or settling
68
colloid
- mixture w medium sized particles
- doesn't settle out
- has Tyndall effect
69
suspension
- largest sized particles
- can be filtered out
- will settle out
- has Tyndall effect
70
What is the difference between metals vs nonmetals vs metalloids?
**metals**
- hard solids with loosely held electrons
- good conductors of heat & electricity (they conduct electricity well because their electrons are more freely moving and floating)
- high melting and boiling points
- can form ionic compounds with nonmetals
- usually gray and shiny
**nonmetals**
- can form ionic compounds with metals (polyatomic
- dull, colorful/colorless substances with tightly held electrons
- low melting and boiling points
- bad conductors of heat and electricity
- 2 or more nonmetals can form covalent compounds (molecules)
**metalloids**
- chemical elements that have properties of metals and nonmetals
- so unoriginal tbh. pmo
71
What are the pieces of evidence of a chemical change?
1. weird color change (ex. clear+clear=pink)
2. formation of gas (bubbles)
3. formation of solid (precipitate=insoluble solid)
4. emission/absorption of energy (heat/light/sound)
5. change in odor/taste
72
hydrogen bonding
where a H molecule is bonded to a F, O, or N molecule (d*-d*)
73
What is another way of expressing id-id forces? Gimme some info on that
- London dispersion forces (LDF)
- nonpolar bonds basically
- the bigger the size, the bigger the attraction
- occur for all substances w electrons but are the only force acting on nonpolar molecules
- results from random/induced elecron fluctuatings, which create tiny, temporary dipoles
74
What is another way of expressing id-d forces?
polar+nonpolar molecules
75
The stronger the IMF attraction, the (harder/easier) it is to separate molecules and evaporate
harder
76
The bigger a molecule, the (more/less) viscous it is.
more
77
The bigger a molecule, the (higher/lower) its boiling or melting point
higher
78
Polar substances tend to have (higher/lower) melting points
higher
79
Nonpolar substances tend to be (more/less) viscous
less
80
magnetism
some solids are magnetic (ex. iron) and can be easily separated from non-magnetic solids
81
chromatography
- separates a homogenous mixture
- mobility rates are based on difference in solubility/absorption
82
electrolysis
chemically separating water using polarity (ex. batteries where negative electrode had less bubbles and brownish tint and positive electrode had more bubles)
83
NO3 -1
nitrate
84
NO2 -1
nitrite
85
bisulfate
HSO4 -1
86
sulfate
SO4 -2
87
sulfite
SO3 -2
88
bicarbonate
HCO3 -1
89
carbonate
CO3 -2
90
phosphate
PO4 -3
91
chromate
CrO4 -2
92
dichromate
Cr2O7 -2
93
ionic bonds/compounds vs metallic bonds/compounds vs covalent bonds/compounds (definition and properties)
**ionic**
- formed when a metal gives up 1 or more electrons to a nonmetal resulting in charged cations and anions
- solid
- strong bond
- high melting and boiling points
- soluble in water
- dissociates in water
- conducts electricity
- oppositely charged ions in an ionic compound arrange themselves in a tightly packed, 3d structure called a crystal lattice
- brittle
- don't conduct electricity when solid but conduct electricity when dissolved in H2O
- ionic substances can be shattered along cleavage lines
**metallic**
- occurs between 2 or more metal atoms
- not soluble in water
- valence electrons in a metallic bond are free-floating and are shared between the metal atoms (the so-called sea of electrons)
- malleable (they deform instead of breaking)
- ductile
**covalent**
- occurs between 2 or more nonmetal atoms
- electrons are shared
- liquids or gases
- weak bond
- don't conduct electricity
- low melting and boiling points
- insoluble in water
- doesn't dissociate in water
- doesn't conduct electricity in water
94
ionic vs covalent
- occurs between metal atoms
- valence electrons in a metallic bond are free-floating and are shared between the metal atoms (the so-called sea of electrons)
95
octet rule
- atoms gain, lose, and share electrons to fill their valence shell with 8 electrons
96
group 16 on periodic table
chalcogens
97
gimme the 3-2-1 staircase
Al (+3)
Zn (+2)
Ag (+1)
98
Roman numerals indicate (+/-) charge
+
99
gimme the 10 prefixes for molecules
1-mono
2-di
3-tri
4-tetra
5-penta
6-hexa
7-hepta
8-octa
9-nona
10-dec a
100
What are the masses in amu of subatomic particles?
protons: 1 amu
neutrons: 1 amu
electrons: 1/1800 amu (essentially 0)
101
more stable isotopes are (more/less) abundant in nature than radioactive isotopes
more
102
What makes up a nuclear symbol?
mass number on northwest corner (protons+neutrons)
atomic number on southwest corner (protons)
103
average atomic mass
a measure of the weighted average mass of all the isotopes in a naturally occurring sample of the element (expressed in amu)
104
explain hyphen notation for something like boron-11 or boron-10
the number after the dash represents the atomic mass of that isotope
