1 Stochiometry Flashcards
What is the main difference between a compound and a mixture?
What is the difference between a liquid (l) and an aqueous solution (aq)
Liquid is a pure element or compound such as water.
Aqueous solution refers to a substance (or solution) dissolved in water.
NaCl(aq) is a solution of sodium chloride in water.
A change from gas to solid is called…
A change from solid to gas is called
The difference between evaporation and boiling is, that…
… boiling happens at the boiling point
… evaporation happens between the melting point and the boiling point.
Calculate the molar mass of
C6H12O6
6(12.01) + 12(1.01) + 6(16.00)
= 180.18 g mol-1
Calculate the molar mass of
(NH4)2SO4
2(14.01) + 8(1.01) + 32.07 + 4(16.00)
= 180.18 g mol-1
What symbol and unit has the relative atomic mass.
(Ar) - no unit
Relative atomic mass or atomic weight is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a given sample to one unified atomic mass unit.
The unified atomic mass unit is defined as being 1⁄12 of the atomic mass of a carbon-12 atom.
Molecules have relative ….. masses.
Ionic compounds have relative ….. masses.
Molecules have relative molecurar masses.
Ionic compounds have relative formular masses.
Abbreviation: Mr
No unit, dimensionless
0.100 mol of (NH4)2SO4
represents :
a. ____ mol of ammonium ions
b. ____ hydrogen atoms
c. ______ atoms in total
a. 0.100 x 2 = 0.200 mol of ammonium ions (NH4)
b. 0.100 x (4x2) x 6.02 x 1023 hydrogen atoms
c. 0.100 x 15 x 6.02 x 1023 atoms
What mass of sodium chloride is produced when chlorine reacts with 52.60 g of sodium Iodide?
Calculate the amount (in mol) in
this 8.80 g of carbon dioxide, CO2
0.200 mol
You shall find the number of a specific atoms in a substance which mass is given in kg?
What are the steps to calculate it?
- Convert the mass of the substance into grams (g).
- Calculate the amount of substance in mol, considering all atoms and using the formular n = m (g) / molar mass
- Consider the number of specific atoms in the substance (for instance H2O has 2 Hydrogen atoms) and mulitply by the molar to have number of atoms in mole
- Multiply with the Avogadro constant of 6.02 x 1023 to get the number of atoms.