Quantities Unit Flashcards
What is the number of Avogadro’s number?
6.022 x 10^23
What is Avogadro’s number (define)
the number of atoms in 12.01 grams of Carbon
What is the Equation for mols avogadro?
n = N/NA (mols = molecules / Avogadro)
What does the symbol N stand for?
molecules, atoms, particles, formula units
what are ATOMS?
Pure, monoatomic elements such as Fe or Na
what are FORMULA UNITS?
Pure ionic compounds like NaCl
A particle composed of two or more nonmetal atoms is a ______?
MOLECULE!
what is the formula for finding mols using mass?
n = m / M (mols = mass / molar mass)
Equation for %composition?
Mass/molar mass of the element youre looking for / m/M of compounds x 100
(m of element/m of cmpd x 100)
what does the empirical formula show?
Shows smallest whole number ratio of each element in a cmpd
what does the molecular formula show?
Sows the actual number of atoms of each element in a cmpd
How do you find the empirical formula?
0.5. the % total should equal 100. % # becomes g.
1. det M of each element
2. find mols of each
3. divide mols by smallest mol
4. round to nearest whole and add to cmpd accordingly
How do you find the molecular formula?
- find mols of each element
- divide mols by smallest
- add to element
- find M of this found cmpd (EF)
- experimental M (should be found in question) / empirical M (EF) = A
- multiply A to the #’s in the EF
How do you find the limiting reactant
- find mols of reactants
- divide both by the known coeff
- multiply both by a chosen unknown coeff
- whichever number is lower is your answer
what is theoretical yield
the amount of product that is predicted by stoichiometric calculations
what is actual yield
the actual amount of product that is recovered after the reaction is complete
what is the formula for percentage yield
actual mols / theoretical mols x 100
how to find the percentage yield?
- find theoretical mol the REACTANT will produce ~ divide by coeff and multiply by chosen product
- use mass of product to calc actual mols
- use formula
