Chemistry basics Flashcards
What defines an element?
The number of protons in the nucleus of its atoms
What is the atomic number?
The number of protons in the element
What is defined as the number of protons in an element’s atoms?
The atomic number
What is the main unit of order in the periodic table?
The atomic number
What does Z refer to in chemistry?
The atomic number
What is the symbol for the atomic number?
z
Why don’t electrons stick closely next to an atom’s protons?
They have high velocity
What does mass refer to?
The amount of something and its inertia
What is defined as the amount of something and its inertia?
Mass
What is measured in grams and kilograms?
Mass
What are example measurements of mass?
grams, kilograms
What is weight?
Weight refers to a force - how much gravity is pulling on an object
What is defined as the force of gravity pulling on an object?
Weight
How is weight measured?
In Newtons
What is measured in Newtons?
Weight
In space, you have ____ but not ____
mass, weight
What is AMU short for?
Atomic mass unit
What is an atomic mass unit?
A very small fraction of a gram, defined as one-twelfth of the mass of a carbon 12
What is the unit of measurement of mass in chemistry?
Atomic mass unit
Does the atomic mass unit refer to mass or weight?
Mass
What is the weighted average of the atomic masses of all an element’s isotopes found on Earth?
The atomic weight
What is atomic weight?
The weighted average of the atomic mass of all the isotopes of an element found on Earth
Does atomic weight refer to weight or mass?
Mass
In this fictional element from the periodic table, what does the number 14 refer to?
The atomic number - the number of protons in the nucleus
In this fictional element from the periodic table, what does the number 29 refer to?
The atomic weight - the weighted average of the atomic masses of all the element’s isotopes as present on Earth
In this fictional element, what does the number 29 refer to?
The mass number - the combined protons and neutrons in this isotope of the element
In this fictional element, what does the number 14 refer to?
The atomic number - the number of protons in this element
What is an alternate name and notation for an AMU?
Da, or Dalton
What is a Dalton?
Another name for atomic mass unit
What number is refered to by a mole?
6.022 x 1023
What measure do we use to translate bewteen AMUs and grams?
The mole
How was Avogadro’s number decided upon?
The number of Carbon 12 atoms in 12 grams of Carbon
What is the significance of the number of Carbon 12 atoms in 12g of Carbon?
This corresponds to Avogadro’s number, the number referred to by a mole - 6.022 X 1023
What’s the easiest way to figure out the mass in grams of one mole of an element?
It is the same as that element’s atomic weight
What is an isotope?
Isotopes are atoms of the same element with different numbers of neutrons in their nuclei.
What is the name for atoms of the same element which have different numbers of neutrons in their nuclei?
Isotopes
Isotopes will have the same ____ number but different ____ numbers
atomic, mass
What does mass number refer to?
The combined number of protons and neutrons in the atom
In chemistry, what does A refer to?
The mass number
How is mass number denominated?
A
What is this?
Protium - the most common isotope of hydrogen
What is deuterium?
An isotope of hydrogen with a neutron and a proton in the nucleus
What is the name of the isotope of hydrogen with a neutron and a proton in the nucleus
Deuterium
What is this:
Tritium - an isotope of hydrogen with two neutrons in its nucleus
What is tritium?
The isotope of hydrogen with two neutrons in its nucleus.
What do you call an atom which has a different number of electrons than protons?
An ion
What is an ion?
An atom which has a different number of electrons and protons
Hydrogen peroxide contains 2 hydrogens and 2 oxygens. What is the empirical formula for hydrogen peroxide?
HO
What is the empirical formula for water?
H2O
What does the empirical formula for a compound indicate?
The simplest ratio of elements contained in a molecular compound, but not the actual number
Which type of formula indicates the simplest ratio of elements contained in a molecular compound?
The empirical formula
Hydrogen peroxide contains 2 hydrogens and 2 oxygens. What is the molecular formula for hydrogen peroxide?
H2O2
What is the molecular formula for water?
H2O
Name each of these formula types for hydrogen peroxide
Structural
Molecular
Empirical
What determines the net charge of an ionic compound?
The net charge is always zero
When is the systemic name of a compound used?
When an ionic compound contains a polyvalent cation.
What is chromium(II) chloride an example of?
The systemic name for an ionic compound (used where a polyvalent cation is present)
What does the II in chromium(II) chloride refer to?
The magnitude of the charge on the chromium cation.
What is a polyvalent element?
It is an element that can combine using different numbers of electrons (thereby showing different valences)
What two types of names are sometimes used in ionic compounds which contain polyvalent elements?
Systemic name: e.g. copper (II)
Common/trivial name: e.g. cupric
What is the name of the process which uses a balanced chemical equation to calculate ratios of reactants and products?
Stoichiometry
Define stoichiometry
The process of using a balanced chemical equation to calculate the ratios of reactants and products
What do you call the numbers used to balance chemical equations?
Stoichiometric coefficients
What are stoichiometric coefficients?
The number used to balance a chemical equation, which can be interpreted as moles
What do mole ratio, stoichiometric factor, and stoichiometric ratio all refer to?
The ratio that indicates the relative proportion of chemicals in a reaction
What are three names for the ratio which indicates the relative proportions of chemicals in a reaction?
Mole ratio, stoichiometric factor, stoichiometric ratio