TEST 1 Flashcards
1 cm3 =
1mL
1mL=
1 cm3
1 angstrom
10^-10 m
10^-10 m
1 angstrom
Conversion between Celsius and Kelvin
1 kelvin degree change = 1 degree change celsius BUT must add 273.15 when converting from celsius to kelvin. T(K)=T(C)+273.15
qualitative vs quantatative
qualitative observations (color, hot or cold, large or small) and quantitative measurements
SI unit length
meter: m
SI unit mass
kilogram: kg
SI unit time
second: s
SI unit temperature
Kelvin: K
SI unit amount of substance
Mole: mol
mass
the measure of the quantity of matter within an object
giga
G (10^9); billion
Mega
M (10^6); million
Kilo
k (10^3) thousand
Deci
d (10^-1) tenth
Centi
c (10^-2) one hundredth
Milli
m (10^-3) one thousandth
Micro
Mu (10^-6) one millionth
Nano
n (10^-9) one billionth
Pico
p (10^-12)
Femto
f (10^-15)
distance between O-H
0.94 Angstroms=9.4 x 10^-11 m
area
m^2
speed
m/s
energy
Joules
1 J=
1 kgm^2/s^2
volume
L; m^3; 1 cm^3=1 mL
density
g/cm^3 = mass/volume
intensive property
property that does not depend on the quantity of matter (i.e. temp, pressure)
extensive property
property that does depend on the quantity of matter (i.e. mass, volume)
matter
anything that takes up space and has mass
weight
the force gravity exerts on an object; directly proportional to the mass of the object
law of conservation of matter
there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change).
classifying matter
mixtures (composed of two or more types of matter that can be present in varying amounts and can be separated by physical changes; can be divided into homogenous (also called a solution, exhibits a uniform composition and appears visually the same throughout.) and heterogeneous (A mixture with a composition that varies from point to point)) vs pure substances (have a constant composition. All specimens of a pure substance have exactly the same makeup and properties; can be divided into elements (cannot be broken down by chem changes) vs compounds (can be broken down by chem changes))
atom
the smallest particle of an element that retains the properties of that element and can enter into a chemical combination; matter is made up of atoms
molecule
A molecule consists of two or more atoms joined by strong forces called chemical bonds. The atoms in a molecule move around as a unit; ring. A molecule may consist of two or more identical atoms or two or more different atoms. if the 2 atoms are identical, it is an element and if they are different, it is a compound. A molecule is the smallest unit of a molecular compound
diatomic molecules
hydrogen (H2), oxygen (O2), phosphorus (P4), sulfur (S8)
A physical property is
a characteristic of matter that is not associated with a change in its chemical composition. (i.e. density, color, hardness, melting and boiling points, and electrical conductivity.) Some physical properties, such as density and color, can be observed without changing the physical state of the matter.
A physical change is
a change in the state or properties of matter without any accompanying change in the chemical identities of the substances contained in the matter. (i.e. when wax melts, when sugar dissolves in coffee, and when steam condenses into liquid water (Figure 1.18). Other examples of physical changes include magnetizing and demagnetizing metals (as is done with common antitheft security tags) and grinding solids into powders (which can sometimes yield noticeable changes in color). In each of these examples, there is a change in the physical state, form, or properties of the substance, but no change in its chemical composition.)
chemical property
The change of one type of matter into another type (or the inability to change) (i.e. include flammability, toxicity, acidity, and many other types of reactivity.)
A chemical change
always produces one or more types of matter that differ from the matter present before the change. (i.e. formation of rust, an explosion of nitroglycerin, reactions that are performed in a lab (such as copper reacting with nitric acid), all forms of combustion (burning), and food being cooked, digested, or rotting)
When adding or subtracting numbers,
round the result to the same number of decimal places as the number with the least number of decimal places`
When multiplying or dividing numbers,
round the result to the same number of digits as the number with the least number of significant figures
If the digit to be dropped (the one immediately to the right of the digit to be retained) is less than 5,
“round down” and leave the retained digit unchanged;
If the digit to be dropped (the one immediately to the right of the digit to be retained) is more than 5,
“round up” and increase the retained digit by 1.
If the dropped digit is 5, and it’s either the last digit in the number or it’s followed only by zeros,
round up or down, whichever yields an even value for the retained digit. If any nonzero digits follow the dropped 5, round up.
precise vs accurate
Measurements are said to be precise if they yield very similar results when repeated in the same manner. A measurement is considered accurate if it yields a result that is very close to the true or accepted value. Precise values agree with each other; accurate values agree with a true value.
1 inch
2.54 cm
2.54 cm
1 inch
1 L
1000 mL
1000 mL
1 L
freezing/boiling points Celsius and Fahrenheit
On the Celsius scale, 0 °C is defined as the freezing temperature of the water and 100 °C as the boiling temperature of the water. The space between the two temperatures is divided into 100 equal intervals, which we call degrees. On the Fahrenheit scale, the freezing point of water is defined as 32 °F and the boiling temperature as 212 °F. The space between these two points on a Fahrenheit thermometer is divided into 180 equal parts (degrees).
dalton’s atomic theory
- Each element is composed of tiny, indestructible (F) particles called atoms.
- All atoms of a given element have the same mass (F) and other properties that distinguish them from the atoms of other elements.
- Atoms combine in simple, whole-number ratios to form compounds.
- Atoms of one element cannot change into atoms of another element. (F) In a chemical reaction, atoms only change the way that they are bound together with other atoms.
radioactivity
a phenomenon in which an atom breaks down, provided evidence that atoms are made of smaller particles.
mass and charge comparison of protons, electrons and neutrons
- The mass of a neutron is similar to that of a proton.
* The proton and electron have equal and opposite charge.
atomic number
number of protons; symbolized by Z; ever element has a unique atomic number
mass number
= # protons + # neutrons
isotopes
Atoms of the same element with a different number of neutrons; Isotopes have the same atomic number and different mass numbers
hydrogen isotope
PROTIUM: 11H; 1 proton, 0 neutrons
DEUTERIUM: 21H; 1 proton, 1 neutron
TRITIUM: 31H; 1 proton, 2 neutrons
the majority of an atom’s mass is located in
The nucleus contains the majority of an atom’s mass because protons and neutrons are much heavier than electrons, whereas electrons occupy almost all of an atom’s volume.
the majority of an atom’s mass is located in
The nucleus contains the majority of an atom’s mass because protons and neutrons are much heavier than electrons, whereas electrons occupy almost all of an atom’s volume.
ion
atom with unequal protons and electrons. Atomic charge = number of protons − number of electrons
anion
An atom that gains one or more electrons will exhibit a negative charge and is called an anion.
cation
Positively charged atoms called cations are formed when an atom loses one or more electrons.
cation
Positively charged atoms called cations are formed when an atom loses one or more electrons.
average mass
the average masses of atoms of most elements are not whole numbers because most elements exist naturally as mixtures of two or more isotopes.
The mass of an element shown in a periodic table or listed in a table of atomic masses is a weighted, average mass of all the isotopes present in a naturally occurring sample of that element. This is equal to the sum of each individual isotope’s mass multiplied by its fractional abundance.
mass spectrometer
a sample is vaporized and exposed to a high-energy electron beam that causes the sample’s atoms (or molecules) to become electrically charged, typically by losing one or more electrons. These cations then pass through a (variable) electric or magnetic field that deflects each cation’s path to an extent that depends on both its mass and charge (similar to how the path of a large steel ball-bearing rolling past a magnet is deflected to a lesser extent than that of a small steel BB). The ions are detected, and a plot of the relative number of ions generated versus their mass-to-charge ratios (a mass spectrum) is made. The height of each vertical feature or peak in a mass spectrum is proportional to the fraction of cations with the specified mass-to-charge ratio.
molecular formula
A molecular formula is a representation of a molecule that uses chemical symbols to indicate the types of atoms followed by subscripts to show the number of atoms of each type in the molecule. (A subscript is used only when more than one atom of a given type is present.) Molecular formulas are also used as abbreviations for the names of compounds. Also, a molecular formula is always a whole-number multiple of an empirical formula.
structural formula
The structural formula for a compound gives the same information as its molecular formula (the types and numbers of atoms in the molecule) but also shows how the atoms are connected in the molecule. A ball-and-stick model shows the geometric arrangement of the atoms with atomic sizes not to scale, and a space-filling model shows the relative sizes of the atoms.
Do a subscript following a symbol and a number in front of a symbol represent the same thing?
a subscript following a symbol and a number in front of a symbol do not represent the same thing; for example, H2 and 2H represent distinctly different species. H2 is a molecular formula; it represents a diatomic molecule of hydrogen, consisting of two atoms of the element that are chemically bonded together. The expression 2H, on the other hand, indicates two separate hydrogen atoms that are not combined as a unit. The expression 2H2 represents two molecules of diatomic hydrogen
empirical formula
indicates the types of atoms present and the simplest whole-number ratio of the number of atoms (or ions) in the compound
isomers
compounds with the same chemical formula but different molecular structures; This small difference in the arrangement of the atoms has a major effect on their respective chemical properties.
