quantative chemistry Flashcards
What does the law of conservation of mass state?
No atoms are lost or gained during a chemical reaction, equations must be balanced.
True or false: The relative atomic mass of an element is weighted average mass of its naturally occurring isotopes.
True.
What elements existed as diatomic molecules.
Hydrogen, oxygen, nitrogen, chlorine, bromine, iodine and fluorine. Their relative formula masses are twice their relative atomic masses.
What is Avogadro’s constant?
The mole: 6.02 x 10^23
mass (m) = ?using moles and rfm
number of moles (n) x relative formula mass (M).
number of moles (n) = ?using mass and rfm
mass (m) ÷ relative formula mass (M)
relative formula mass (M) = ?using mass and moles
mass (m) ÷ number of moles (n)
number of particles = ?using moles
number of moles (n) x Avogadro’s constant (Na)
If there are (a) reactants in a chemical reaction and there is (b) of one of them, then the other reactant is called the (c) reactant.
(a) 2
(b) excess
(c) limiting
How is the limiting reactant identified?
By comparing the number of moles of each reactant with those required by the balanced symbol equation.
In a (a) the substance dissolved is called the (b) and the liquid in which it dissolves in is called the (c)
(a) solution
(b) solute
(c) solvent
True or false: The greater the number of moles of solute is dissolved in a solution, the less concentrated it is.
False.
In what 2 ways can the concentration of solutions we use the amount of solute dissolved in 1 dm cubed.
- in grams of solute per dm cubed of solution.
- in moles of solute per dm cubed of solution.
mass solute in grams= ?using conc. and volume
concentration in grams x volume
number of moles of solute= ?using conc. and volume
concentration in moles x volume
