Unit 4 Flashcards
(17 cards)
What do the prefixes mono-, di-, tri and tetra mean when used in a name?
Mono- one
Di- Two
Tri- Three
Tetra- 4
- How do you find the valency for an element?
Using the Periodic Table in the Data Booklet
- Write formulae for compounds with two elements using valency e.g. potassium fluoride, aluminium oxide, magnesium nitride.
KF
Al2O3
Mg3N2
- How do you find the valencies for group/complex ions?
Page 8 of the Data Booklet (the number in front of their charge)
Write formulae for compounds
involving group/complex ions using valency
e.g. calcium carbonate, zinc (II) nitrate, sodium sulfate, magnesium hydroxide.
CaCO3
Zn(NO3)2
Na2SO4
Mg(OH)2
Write formulae for transition metal compounds if Roman numerals are given e.g. iron(III) oxide, vanadium(V) oxide, copper(II) hydroxide.
Fe2O3
V2O5
Cu(OH)2
. Write ionic formulae for compounds e.g. calcium oxide, magnesium hydroxide, sodium carbonate, cobalt(II) chloride.
Ca2+O2-
Mg2+(OH-)2
(Na+)2CO32-
Co2+(Cl-)2
How would you find out the relative atomic mass of an element?
Use the Data Booklet
- Calculate relative formula masses from relative atomic masses e.g. chlorine, sulfur dioxide, magnesium phosphide, ammonium sulfate.
Chlorine (Cl2)- 35.5 x 2 = 71
Sulfur dioxide (SO2)- 32 + (2 x 16) = 64
Magnesium phosphide (Mg3P2)- (3 x 24.5) + (2 x 31) = 135.5
Ammonium sulfate ((NH4)2SO4) - (2 x 14) + (8 x 1) + 32 + (16 x 4) = 132
- What is the formula mass in grams called?
GFM
- Write the triangle to show how mass and moles are related.
m = n x GFM
m = mass in grams
n = num of moles
GFM = gram formula mass
- Using the triangle calculate the number of moles from a given mass e.g. 1.6g of oxygen, 117g of NaCl.
A) 1.6g of Oxygen
Moles = mass/GFM 1.6/32 = 0.05
B) 117g of NaCl
Moles = mass/GFM 117/58.5 = 2
- Using the triangle calculate a mass from a given number of moles e.g. 0.1 mol of bromine, 0.02 mol of sodium hydrogen carbonate (NaHCO3).
A) 0.1 mol of bromine
Mass = moles x GFM 0.1 x 160 = 16.0g
B) 0.02 mol of sodium hydrogen carbonate
Mass = moles x GFM 0.02 x 84 = 1.68g
- Using the triangle, calculate the gfm from a given mass and number of moles e.g. 2 mol weighs 60g, 0.5 mol weighs 9g.
A) 2 mol weighs 60g
GFM= mass/moles 60/2 = 30
B) 0.5 mol weighs 9g
GFM= mass/moles 9/05 = 18
Balance equations given formulae equations e.g.
(i) C3H8 + O2 → CO2 + H2O
(ii) NH3 + H3PO4 → (NH4)3PO4
(i) C3H8 + 5O2 → 3CO2 + 4H2O
(ii) 3NH3 + H3PO4 → (NH4)3PO4
Write balanced equations given a reaction in words e.g.
(i) nitrogen reacts with hydrogen giving nitrogen hydride (ammonia),
(ii) lithium hydroxide reacts with carbon dioxide giving lithium carbonate and water.
(i) N2 + 3H2 → 2NH3
(ii) 2LiOH + CO2 → Li2CO3 + H2O
Calculate the mass of a reactant or product from a balanced equation e.g.
(i) 2NaN3 → 2Na + 3N2
Calculate the mass of N2 produced from 60g of NaN3.
(ii) CaCO3 + SO2 → CaSO3 + CO2
Calculate the mass of CaCO3 required to react with 580kg of SO2.
(i) mol NaN3 = 60/65 = 0.92
from the equation 2 mol NaN3 → 3 mol N2 or 1 mol NaN3 → 1.5 mol N2
therefore 1.38 mol produced = 1.38 x 28 = 38.8 g
(ii) CaCO3 + SO2 → CaSO3 + CO2
Mole SO2 = 580000/64 = 9062.5
mole CaCO3 = 9062.5 (1:1 from balanced equation)
mass CaCO3 = 9062.5 x 100 = 906250g or 906.25kg
