1. List Evidences of a Chemical Change

Test 7 Review

1. List evidences of a chemical change.

2. Write out the following reactions as chemical equations. Then make sure they are balanced.

A.Nitrogen gas reacts with hydrogen gas to produce liquid ammonia (NH3).

B.Iron(III) hydroxide breaks into Iron(III) oxide and water vapor when heated.

3. Do the following reactions occur? If so, write the products and then balance the equations.

A. AlBr3 + Cl2 

B. Fe + Al2O3 

C. Na + H2O 

4. Determine if the reaction occurs. If the reaction does occur, balance the equation, determine states of matter, and write the ionic and net ionic equations.

A. Al + FeCl2 

B. Na + Mg(NO3)2

5. Balance the equations of the following reactions. Then, classify each as: synthesis (S),
decomposition (D), combustion (C), single replacement (SR), double replacement (DR) or other (O).
______1. ____ Na(s) +____ H2O(l) → ____ NaOH(aq) + ____ H2(g)

______2. ____ CO(g) + ____ O2(g) → ____ CO2(g)

______3. ____ FeS(s) + ____ HCl(aq) → ____ FeCl2(aq) + ____ H2S(g)

______4. ____ NaNO3(s) →____ NaNO2(s) + ____ O2(g)

______5. ____ H2S + I2 + H2O -> H2SO4 + HI

______6. ____ Fe(s) + ____ CuNO3(aq) → ____ Fe(NO3)2(aq) + ____ Cu(s)

______7. ____ KI(aq) + ____ Cl2(g) → ____ KCl(aq) + ____ I2(aq)

______8. ____ Al(s) + ____ S(s) → ____ Al2S3(s)

______9. ____ KClO3(s) → ____ KCl(s) + ____ O2(g)

______10. ____ C4H10(g) + ____ O2(g) → ____ CO2(g) + ____ H2O(g)

6. Find the mass of the other reactants and products.
Mg + 2 NaF →MgF2 + 2 Na5.0 g NaF

7. Calculate all masses and volumes not given.

CaCO3(s) CO2(g) + CaO(s)7.62 g CaCO3
Find L of CO2 and g of CaO

7. Determine the limiting reagent
NH4NO3 + Na3PO4 (NH4)3PO4 + NaNO3
30.0 g NH4NO3
50.0 g Na3PO4

8. Calculate the percent yield (2 decimal places).
H2 + O2 H2O
What is the % yield of H2O if 138 g H2O is produced from 16 g H2 and excess O2?

Test 7 Review KEY

List evidences of a chemical change.

Form a precipitate, form a gas, release energy, color change,

2. Write out the following reactions as chemical equations. Then make sure they are balanced.

A.Nitrogen gas reacts with hydrogen gas to produce liquid ammonia (NH3).

N2(g) + 3H2(g) -> 2NH3(l)

B.Iron(III) hydroxide breaks into Iron(III) oxide and water vapor when heated.

2Fe(OH)3(s) -> 2Fe2O3(s) + 3H2O(g)

heat

3. Do the following reactions occur? If so, write the products and then balance the equations.

A. AlBr3 + Cl2 yes because Cl is above Br on the activity series

2AlBr3 + 3Cl2 -> 2 AlCl3 + 3Br2

B. Fe + Al2O3 no because Fe is below Al on the activity series

C. Na + H2O yes because Na reacts with water, replacing 1 hydrogen

2Na + 2 H2O -> 2NaOH + H2

4. Determine if the reaction occurs. If the reaction does occur, balance the equation, determine states of matter, and write the ionic and net ionic equations.

A. Al + FeCl2 Al can replace Fe, and FeCl2 is soluble so reaction happens

2Al(s) + 3FeCl2(aq) -> 2AlCl3(aq) + 3 Fe(s)

Ionic Equation:2Al + 3Fe+2 + 6Cl- -> 2Al+3 + 6Cl- + 3Fe

Net Ionic Equation:2Al + 3Fe+2 -> 2Al+3 + 3Fe

B. Na + Mg(NO3)2Na can replace Mg, and Mg(NO3)2is soluble

2Na(s) + Mg(NO3)2(aq) 2NaNO3(aq) + Mg(s)

Ionic Equation:2Na + Mg+2 + 2NO3- -> 2Na+ + 2NO3-+ Mg

Net Ionic Equation:2Na + Mg+2 -> 2Na+ + Mg

S or C 2. 2CO(g) + O2(g) → 2CO2(g)

DR 3. FeS(s) + 2HCl(aq) → FeCl2(aq) + H2S(g)

D 4. 2NaNO3(s) 2NaNO2(s) + O2(g)

O 5. H2S + 4I2 + 4H2O -> H2SO4 + 8HI

SR 6. Fe(s) + 2CuNO3(aq) → Fe(NO3)2(aq) + 2Cu(s)

SR 7. 2KI(aq) + Cl2(g) → 2KCl(aq) + I2(aq)

S 8. 2Al(s) + 3S(s) → Al2S3(s)

D 9. 2KClO3(s) → 2KCl(s) + 3O2(g)

C10.2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(g)

6. Find the mass of the other reactants and products.
Mg + 2 NaF →MgF2 + 2 Na

5.0 g NaF (1 molNaF/41.99 g NaF)(1 mol MgF2/2 molNaF)(62.31 MgF2/1 mol MgF2) = 3.71g MgF2

5.0 g NaF (1 molNaF/ 41.99 g NaF)(1 mol Mg/2 molNaF)(24.31g Mg/1 mol Mg) =1.45 g Mg

5.0 g NaF(1 molNaF/ 41.99 gNaF)(2molNa/2 molNaF)(22.99g Na/1 molNa) = 2.74g Na

7. Calculate all masses and volumes not given.

CaCO3(s) CO2(g) + CaO(s)

7.62 g CaCO3
Find L of CO2 and g of CaO

7.62 g (1 molCaCO3/ 100.09g CaCO3)(1 molCO2/1 molCaCO3)(22.4 L CO2/1 molCO2) = 1.71 L CO2

7.62 g (1 molCaCO3/ 100.09g CaCO3)(1 molCaO/1 molCaCO3)(56.08CaO/1 molCaO) = 4.27 g CaO

7. Determine the limiting reagent
3NH4NO3 + Na3PO4 (NH4)3PO4 + 3NaNO3
30.0 g NH4NO3(1 molNH4NO3/80.06 g NH4NO3)(3molNaNO3/3molNH4NO3)(85.00 g NaNO3/1 molNaNO3) = 32.23 g NaNO3
50.0 g Na3PO4(1 molNa3PO4/ 163.94g Na3PO4)(3molNaNO3/1 molNa3PO4)(85.00 g NaNO3/1 molNaNO3) =77.77 g NaNO3
NaNO3is the limiting reagent

8. Calculate the percent yield (2 decimal places).
2H2 + O2 2H2O
What is the % yield of H2O if 138 g H2O is produced from 16 g H2 and excess O2?

16 g H2(1 molH2/2.02 g H2)(2 molH2O /2 molH2)(18.02 g H2O /1 molH2O) = g H2O

138 g H2O / 142.73 g H2O = 96.69%