Outcome 2
Topic 1 ‐ Wring and Balancing Chemical Reacons
‐ In a chemical reacon, atoms in the products rearrange to form the products of the reacon
***Remember chemical reacons create new compounds***
‐ A word equaon used words to represent the chemical reacon occurring
Magnesium + hydrochloric acid → hydrogen gas + magnesium chloride
‐ A formula equaon uses the chemical formulas of the reactants and products to represent the chemical reacon
Mg(s) + HCl (aq) → H2(g) + MgCl 2(aq)
‐ Remember the law of conservaon of mass states that the number of atoms in the reactants must equal the number of atoms in the products.
‐ To make sure the atoms are equal, we have to balance the chemical equaon.
___ Mg(s) + ___ HCl(aq) → ___ MgCl2(aq) + ___ H2(g)
_____ SnF4(aq) + _____ Cr(s) à _____ CrF3(aq) + _____ Sn(s)
_____ (NH4)3PO4(aq) + _____ CaBr2(aq) à _____ Ca3(PO4)2(s) + _____ NH4Br(aq)
_____ CH3COOH(aq) + _____ Ba(OH)2(aq) à _____ Ba(CH3COO)2(aq) + _____ H2O(l)
_____ C5H10(g) + _____ O2(g) à _____ CO2(g) + _____ H2O(g)
_____ C8H18(l) + _____ O2(g) à _____ CO2(g) + _____ H2O(g)
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Practice Sheet 8
In the following exercises, recall that many of the non­metal elements exist as molecules, such as H2(g) or S8(s). Rewrite the following word equations as formula equations and then balance them:
a) solid sodium metal reacts with chlorine gas to produce solid sodium chloride
b) solid potassium metal reacts with oxygen gas to produce solid potassium oxide
c) hydrogen gas reacts with oxygen gas to produce liquid water
d) solid potassium chlorate decomposes into oxygen gas and solid potassium chloride
e) solid aluminium oxide is decomposed into solid aluminium and oxygen gas
f) mercury(II) sulfide is decomposed into liquid mercury and solid sulfur g) aqueous cobalt(III) nitrate reacts with solid zinc to produce aqueous zinc nitrate and solid cobalt
h) fluorine gas reacts with aqueous lead(IV) iodide to produce aqueous lead(IV) fluoride and solid iodine
i) aqueous gold(III) bromide reacts with solid silver metal to produce solid silver bromide and solid gold metal
j) aqueous sodium sulfate reacts with aqueous strontium hydroxide to produce aqueous sodium hydroxide and solid strontium sulfate
k) aqueous thallium(I) hydroxide reacts with aqueous magnesium bromide to produce solid magnesium hydroxide and solid thallium bromide
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l) methane gas reacts with oxygen gas to produce carbon dioxide gas and water vapour
Balance the following chemical equations: _____ Na(s) + _____ O2(g) à _____ Na2O(s)
a)
b)
_____ Al(s) + _____ Cl2(g) à _____ AlCl3(s)
c)
_____ N2(g) + _____ O2(g) à _____ NO2(g)
d)
_____ HI(g) à _____ H2(g) + _____ I2(s)
e)
_____ NH3(g) à _____ H2(g) + _____ N2(g)
f)
_____ Al2S3(s) à _____ Al(s) + _____ S8(s)
g)
_____ BN(s) + _____ Cl2(g) à _____ BCl3(g) + _____ N2(g)
h)
_____ SnF4(aq) + _____ Cr(s) à _____ CrF3(aq) + _____ Sn(s)
i)
_____ Mg(s) + _____ HCl(aq) à _____ MgCl2(aq) + _____ H2(g)
j)
_____ (NH4)3PO4(aq) + _____ CaBr2(aq) à _____ Ca3(PO4)2(s) + _____ NH4Br(aq)
k)
_____ Pb(NO3)4(aq) + _____ K2Cr2O7(aq) à _____ Pb(Cr2O7)2(s) + _____ KNO3(aq)
l)
_____ AgClO4(aq) + _____ Na3PO4(aq) à _____ NaClO4(aq) + _____ Ag3PO4(s)
m)
_____ HCl(aq) + _____ Ca(OH)2(s) à _____ CaCl2(aq) + _____ H2O(l)
n) __ CH3COOH(aq) + ___ Ba(OH)2(aq) à __ Ba(CH3COO)2(aq) + ___ H2O(l)
o)
_____ C3H8(g) + _____ O2(g) à _____ CO2(g) + _____ H2O(g)
p)
_____ C6H14(l) + _____ O2(g) à _____ CO2(g) + _____ H2O(g)
q)
___ C3H6OS2(s) + ___ O2(g) à ___ CO2(g) + ___ H2O(g) + ___ SO2(g)
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