#42 the equation for the formation of water from its elements, h 2 (g) + o 2(g) h 2 o (l) can be...

#42 The equation for the formation of water from its elements, H2 (g) + O2(g) H2O(l) can be “balanced”by changing the formula of the product toH2O2. Explain why this is incorrect.

To change the subscripts like thatactually changes the product to a totally different one. You cannot touch the subscripts to “balance” theequation, only add coefficients.

#43. Balance the following equations:

a. PbO2 PbO + O22 2

b. Fe(OH)3 Fe2O3 + H2O2 3

c. (NH4)2CO3 NH3 + H2O + CO2

d. NaCl + H2SO4 Na2SO4 + HCl2

2

2

#44 What is a characteristic of every combination reaction?

Every combination reaction has a single product. example:

2H2 + O2 2H2O

single product

#45 Write balanced chemical equationsfor the following combination reactions.

b. P + O2 diphosphorous pentoxide

4P + 5O2 2P2O5

c. Ca + S CaS

a. Mg + O2 2MgO2

#46 What is a distinguishing feature of every decomposition reaction?

a decomposition always has a singlereactant. example:

2H2O 2H2 + O2

#47 Write a balanced chemicalequation for each decompositionreaction:

a. Ag2O(s) Ag + O22

b. ammonium nitrate dinitrogen monoxide

+ water NH4NO3 N2O + 2H2O

4

#48 Use the activity series of metalsto write a balanced equation for eachsingle-replacement reaction.

a. Au(s) + KNO3NO reaction. K ishigher on the chartthan Au

b. Zn(s) + AgNO3

c. Al(s) + H2SO4

Zn(NO3)2(s) + Ag22

Al2(SO4)3 + H22 3 3

#49 write a balanced equationfor each of the following double-replacement reactions.

a. H2C2O4(aq) + 2KOH(aq)

2H2O + K2C2O4

b. CdBr2(aq) + Na2S(aq)

CdS + 2NaBr

#50 What is common to all combustionreactions?

oxygen on the left side

example:

C4H8 + 6O2 4CO2 + 4H2O

#51 Write a balanced equation forthe complete combustion of eachcompound.a. Butene (C4H8)

C4H8 + 6O2 4CO2 + 4H2O

b. acetone (C3H6O)

C3H6O + 4O2 3CO2 + 3H2O

#52 Balance each equation and identifyits type.

a. Hf + N2 Hf3N43 2a combination reaction

b. Mg + H2SO4 MgSO4 + H2

a single-replacement reaction

c. C2H6 + O2 CO2 + H2O642 7

a combustion

#52 Balance each equation and identifyits type.continued….

d. Pb(NO3)2 + NaI PbI2 + NaNO32 2

e. Fe + O2 Fe2O334 2

a double-replacement reaction

a combination reaction