Quantitative chemistry Flashcards
What is Relative formula mass of a compound?
It is the sum of a compound is the sum of the relative atomic masses of atoms in the numbers shown in the formula
How do you find the percentage mass of an element in a compound?
Mass of the the atom/ Total mass of the compound x 100
What is Avogadro constant number?
6.02 x 10 to the power of 23 which means one mole of an amount equals this.
What is the formula to find out the total amount of Moles (Mol)
Mass(g)/Relative atomic masses Ar
What is the formula to find out the Mass(g)
Number of moles x Relative formula mass
What is the law of conservation?
No atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants
46g of sodium reacts with 32g of oxygen. caluclate the mass of sodium oxide produces.
It produces 78g due to the conservation of mass.
If Mass changes in a chemical reaction what is usually involved?
A Gas
How do you can you balance an equation by using the mole equation?
1) Find the mole of the number
2) Divide by the smallest number of moles in the reaction
3) If any of the numbers are not whole numbers multiply all of the numbers by the same amount to get whole numbers
4) Write balanced symbol equation for the reaction by putting the number in front of the chemical reaction.
What do you call a reactant that is fully used up?
Limiting reactant
What do you call a reactant which isn’t fully used up?
Excess reactant
How many moles of zinc iodide would be produced if we used 0.5 moles of zinc and 1 mole of iodine , calculate the mass of the product. Ar Zn= 65. Ar I=127
0.5 moles would be produced and to find mass you do
Number of moles x relative formula mass 0.5 x 319=159.5g
What is Concentration?
It is a measure of how crowded things are
What is the formula for the concentration of Solutions?
Concentration( in g/dm3) = Mass of solute(g)/Volume of solvent in dm3
If we increase the mass of solute and keep the volume the same what happens to the concentration?
It increases
