Ch 5 - Quantifying Chemistry
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
atomic number
the number of protons in the nucleus of an atom
atomic mass
the number of protons and neutrons in the nucleus of an atom
relative atomic mass (symbol Ar)
the average mass of the naturally occuring isotopes of the element relative to the mass of an atom of carbon-12, which is given a mass of exactly 12 it is found by comparing the mass of an atom with the mass of an atom of carbon-12
relative molecular mass, Mr (RMM)/Relative Formula Mass (RFM)
(the sum of the individual relative atomic masses of the atoms that make up a molecule/compound) is the mass of a molecule of the compound relative to the mass of an atom of carbon-12, which is given a mss of exactly 12
isotopes
atoms of the same element which have the same number of protons but a different number of neutorns
relative isotopic mass
an isoptope of an element is the mass of one atom of that isotope relative to the mass of an atom of carbon-12
mole
the amount of substance that has the same number of particles (atoms, molecules, ions etc) as there are atoms in exactly 12g of carbon-12 mole = in refernece to a sentence mol = unit
molar mass (gmol-1)
the mass of one mole of a compound, expressed in grams. Thus one mole of carbon-12 has a mass of exactly 12g. One moleof sodium-23 has a mass of 23g and so on
Avogadro’s number
the number of particles in a mole i.e. 6.023 x 1023 = 1 mole
what does the atomic number also equal?
number of protons number of electrons
what is magnesium’s atomic mass in comparison to carbon
C : Mg 12 : 24 1 : 2 you divide by the smallest number or smallest factor of the two numbers
what is the relative molecular mass (RMM) of CO2?
C = 12 0= 16 12 + (16 x 2) =44
what is the relative molecular mass (RMM) of Ca (OH)2
Ca = 40 O = 16 H = 1 Ca + (O x 2) + (H x 2) =74
what is the relative molecular mass (RMM) of CuSO4 • 5 H2O
Cu = 63.5 S = 32 O = 16 H = 1 63.5 + 32 + (16x4) • (1 x 2 x 5) + (16 x 5) 159 • 90 (the • means for every CuSO4 there are five H2O) =249.5
How do you find the % mass?
% mass = RMM of element ÷ RMM of compound x 100%
Find the percentage of oxygen in Ca (OH)2
O = 16 Ca = 40 H = 1 (2 x 16) ÷ 74 = 32 ÷ 74 x 100% =43.2%
Calulate the relative molecular mass (Mr) of NH4NO3
N = 14 H = 1 O = 16 14 + (1 x 4) +14 + (16 x 3) = 80
Calculate the relative molecular mass (Mr) of Al2(SO4)3
Al = 27 S = 32 O = 16 (27 x 2) + (32 x 3) + (16 x 4 x 3) = 342
Calculate the relative molecular mass of H2C2O4 • 2H2O
H = 1 C = 12 O = 16 (1 x 2) + (12 x 2) + (16 x 4) • (2 x 1 x 2) + (2 x 16) 90 • 36 = 126
Calculate the percentage by mass of C in CH4
12 ÷ 16 x 100 = 75%
Calculate the percentage by mass of O in Ca(NO3)2
(16 x 3 x 2) ÷ 164 x 100 = 58.5 %
Calculate the percentage by mass of O in Fe(NO3)3
(16 x 3 x 3) ÷ 56 + (14 x 3) + (16 x 3 x 3) = 242 133 ÷ 242 x 100% =59.5%
How many molecules are in one mole of CO2?
6.02 x 1023 molecules
How many atoms are in one mole of CO2?
because there are 3 atoms in 1 molecule of CO2? 3 x 6.02 x 1023 = 18.06 x 1023 atoms