Flashcards
Moles
Flashcards do conjunto (13)
- 1What are the three subatomic elements and what are their charges and mass?Protons: +1 charge, 1 amu
Neutrons: 0 charge, 1amu
Electrons: -1 charge, 1/2000 amu - 2Number of protons= ? Number of protons + neutrons =?# protons= atomic number/proton number
# protons and neutrons= mass number/atomic mass - 3What are isotopes?Atoms with the same number of protons but a different number of neutrons
- 4Define 1 amu1/12 the mass of 1 carbon 12 isotope
- 5Define relative atomic massRelative atomic mass or A subscript r is the weighted average of the isotopic masses of the element compared to the mass of one twelfth of a carbon 12 isotope
- 6How do you calculate the Ar of an element?1. put the percentage over 100
2. multiply that percentage by the mass number of that isotope
3. add however many isotopes there are and that's the Ar - 7What is a mole?A mole is a very large number of any particles.
One mole of particles is 6 x 10^23 particles (Avogadro's number, or N, NA) - 8What is 1 mole of hydrogen?1.0g
(aka, the molar mass of hydrogen is 1.0g per mole) - 9What is the relative molecular mass?Relative molecular mass is Mr. FoR MOLECULES
It is adding all of the relative atomic masses together by the number of atoms there are (eg: H20
(2x1) + (1x16)=18 - 10How to find the percentage composition of elements in compounds1. put the total atomic number over the Mr
2. multiply by 100 and get the % - 11the empirical formula...gives lowest whole number ratio of the different atoms in a sample of a compound.
- 12The molecular formula...requires knowing the Mr
1. all you have to do is figure out how many more times the value of the Mr is from the Mr of the empirical formula. divide the big Mr by the small Mr and get how many more TIMES
2. then multiply this number on all of the individual elements - 13Calculating the EF and MF1. list all the grams your given
2. put it over the Mr
3. you get the moles
4. put it over the lowest common denominator
5. you get a number
6. put those numbers back in and that's the empirical formula
7. divide the Mr by the Mr of the empirical formula
8. use what you got and plug it back in to the formula
9. you get the MF
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- Chemistry FlashCards sobre Moles, criado por Nicole Engen em 03-05-2017.
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- Nicole Engen
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