12/20/25, 10:26 PM CHEM 1301A midterm Flashcards | Quizlet
CHEM 1301A midterm exam with question and
answer 100%correct
C
Terms in this set (124)
Atoms Building blocks of matter
- Protons: + charge, found in nucleus
- Electrons: - charge, outside nucleus, very light
- Neutrons: no charge, found in nucleus
Atomic Number The number of protons in the nucleus of an atom
Mass Number The sum of the number of neutrons and protons in an atomic
nucleus
Isotopes Atoms with the same number of protons but a different
number of neutrons
- Have same atomic number but different mass
Isotopic Abundance Average atomic mass =
(% isotopic abundance/100) x isotopic mass
Ions Positively and negatively charged atoms
- Cation: loses an electron, becomes more +
- Anion: gains an electron, becomes more -
Molecules Groups of two or more atoms held together by chemical
bonds
- Compound: molecule containing atoms of more than one
element
- Diatomic: only 2 atoms (HOBrFINCl)
- Polyatomic: more than 2 atoms (H2O)
Moles The number of atoms contained in exactly 12g of pure C-12
-NA: 6.02x10^23
- # mol x NA = # particles
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, 12/20/25, 10:26 PM CHEM 1301A midterm Flashcards | Quizlet
Molar Mass The mass of one mole of molecules
- sum of atomic masses of all the atoms in a molecule
- n = m/MM
Mass % mass % = (mass of one species / total mass of sample) x 100%
- useful for: % of an element in a compound, % of a compound
on a mixture
Empirical and Molecular Formulas - Empirical: the simplest ratio of atoms in a molecule
- Molecular: whole ratio
- Steps to find molecular from empirical:
1. m/MM to find moles
2. divide by smallest n to get the ratio
3. multiply to get to the nearest whole number
Mole Fraction and % Mole fraction: # n of one species / total n
Mole %: (# n of one species / total n) x 100%
Average Molar Mass of Mixtures MM = (Xa x MMa) + (Xb x MMb) + (Xc x MMc) etc.
- X is the mole fraction
Molarity The number of moles of solute per liter of solution
- M = amount of solute (n) / amount of solution (n)
- M = n/V
- molarity may change if temp. changes because temp. affects
volume
Dilution Reducing the concentration of a solution
- number of moles of solute does not change, given that no
chemical reaction takes place
- M1V1 = M2V2
Density of a Solution d = mass of solution / volume of solution
- always refers to entire solution
ppm and ppb ratio of the mass of solute to the mass of solution (same units)
and multiplied by 1 million/billion
- ppm/b = (mass solute / mass soltution) x 10^6 or 9
- ppm: mass solute is very small compared to very small
relative to mass of solution
- ppm: very low concentrations of solute
Law of Conservation of Mass The combined mass of the reactants equals the combined
mass of the products
% Yield % yield = (actual yield/theoretical yield) x 100
- theoretical yield gives the amount of product that would be
produced if the reaction went perfectly
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CHEM 1301A midterm exam with question and
answer 100%correct
C
Terms in this set (124)
Atoms Building blocks of matter
- Protons: + charge, found in nucleus
- Electrons: - charge, outside nucleus, very light
- Neutrons: no charge, found in nucleus
Atomic Number The number of protons in the nucleus of an atom
Mass Number The sum of the number of neutrons and protons in an atomic
nucleus
Isotopes Atoms with the same number of protons but a different
number of neutrons
- Have same atomic number but different mass
Isotopic Abundance Average atomic mass =
(% isotopic abundance/100) x isotopic mass
Ions Positively and negatively charged atoms
- Cation: loses an electron, becomes more +
- Anion: gains an electron, becomes more -
Molecules Groups of two or more atoms held together by chemical
bonds
- Compound: molecule containing atoms of more than one
element
- Diatomic: only 2 atoms (HOBrFINCl)
- Polyatomic: more than 2 atoms (H2O)
Moles The number of atoms contained in exactly 12g of pure C-12
-NA: 6.02x10^23
- # mol x NA = # particles
https://quizlet.com/ca/336155213/chem-1301a-midterm-flash-cards/ 1/12
, 12/20/25, 10:26 PM CHEM 1301A midterm Flashcards | Quizlet
Molar Mass The mass of one mole of molecules
- sum of atomic masses of all the atoms in a molecule
- n = m/MM
Mass % mass % = (mass of one species / total mass of sample) x 100%
- useful for: % of an element in a compound, % of a compound
on a mixture
Empirical and Molecular Formulas - Empirical: the simplest ratio of atoms in a molecule
- Molecular: whole ratio
- Steps to find molecular from empirical:
1. m/MM to find moles
2. divide by smallest n to get the ratio
3. multiply to get to the nearest whole number
Mole Fraction and % Mole fraction: # n of one species / total n
Mole %: (# n of one species / total n) x 100%
Average Molar Mass of Mixtures MM = (Xa x MMa) + (Xb x MMb) + (Xc x MMc) etc.
- X is the mole fraction
Molarity The number of moles of solute per liter of solution
- M = amount of solute (n) / amount of solution (n)
- M = n/V
- molarity may change if temp. changes because temp. affects
volume
Dilution Reducing the concentration of a solution
- number of moles of solute does not change, given that no
chemical reaction takes place
- M1V1 = M2V2
Density of a Solution d = mass of solution / volume of solution
- always refers to entire solution
ppm and ppb ratio of the mass of solute to the mass of solution (same units)
and multiplied by 1 million/billion
- ppm/b = (mass solute / mass soltution) x 10^6 or 9
- ppm: mass solute is very small compared to very small
relative to mass of solution
- ppm: very low concentrations of solute
Law of Conservation of Mass The combined mass of the reactants equals the combined
mass of the products
% Yield % yield = (actual yield/theoretical yield) x 100
- theoretical yield gives the amount of product that would be
produced if the reaction went perfectly
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