Balance equationsDalton Atomic model: In a chemical reaction, atoms only change theway that they are bound together with other atoms( page 49). For example: H + O → H-O (water)Dalton used hooks rather thanline bonds.

Electrolysis of water suggested water’s formula is actually H-O-H.

There are 7 diatomic elemental gases: H2, O2, N2, F2, Cl2, Br2, and F2 .

This leads to: H-H + H-H + O=O → H-O-H + H-O-H 4 H’s and 2 O’s are rearranged on each side. This balanced equationcan be written as: 2 H2 + O2 → 2 H2O

2 moles of H2 react with 1 mole of O2 to form 2 moles of H2O.

Balance equations/solve problemsBalance the following equations:1. Al2S3 + H20 Al(OH)3 + H2S

2. Bi2O3 + C → Bi + CO

3. Cu2S + O2 → Cu2O + SO2

4. N2H4 + Dinitrogen dioxide → Nitrogen gas + H2O

5. C2N2 + H2O → H2C2O4 + NH3

6. CaSiO3 + HF → SiF4 + CaF2 + H2O7. Iron + hydrogen chloride → iron(II) chloride + hydrogen gas. 8. Iron + hydrogen chloride → iron(III) chloride + hydrogen gas9. Phosphorus pentachloride + H2O → phosphoric acid + HCl

10. Sulfur hexafluoride reacts with water to form hydrogen sulfate and hydrogen fluoride.11 Nitrogen dioxide reacts with water to form hydrogen nitrate and nitrogen monoxide (nitric oxide).

Balance equations/solve problems

Solve the following problems: Be sure to correctly balance the equation.

1. Al2S3 + H20 Al(OH)3 + H2S Calculate the moles of Al2S3

that reacts with 456 g (1.0 pint )of water. ANS: 4.22 mole

2. Al2S3 + H20 Al(OH)3 + H2S Calculate the mass of H2S that forms from 456 g of water. ANS: 432 g

3. Bi2O3 + C → Bi + CO Calculate the mass of Bi2O3 needed to form 1.26 X 10-6 g Bi. ANS: 1.40 X 10-6 g

Balance equations/solve problemsSolve the following problems: Be sure to correctly balance the equation

1. Nitrogen dioxide reacts with water to form hydrogen nitrate and nitrogen monoxide (nitric oxide). Calculate the moles of hydrogen nitrate formed when 165 g of nitrogen dioxide react. ANS: 2.39 mol

2. Sulfur hexafluoride reacts with water to form hydrogen sulfate and hydrogen fluoride. Calculate the mass of hydrogen fluoride formed when 13.4 g of

sulfur hexafluoride react. ANS: 11.0 g

3. Copper (II) sulfide reacts with oxygen gas to form copper (II) oxide and sulfurdioxide. Calculate the mass of copper (II) sulfide necessary to form 1.0 kg of copper(II)oxide. (= 1202 g) ANS: 1200 g CuS ← last 0 not sig.fig.

Balance equations/solve problemsCoal (carbon) combines with oxygen gas (combustion) to form carbondioxide and generate heat (kj). Natural gas (methane) combines with oxygen gas(combustion) to form carbon dioxide and water and generate heat (kj).

1. Write balanced equations showing the combustion of coal and natural gas with oxygen gas.

2. 1.0 kg of coal (carbon) produces 32800 kj. Calculate the energy produced by 1.0 mole of coal and add this energy to the product side of the equation.

ANS: 394 kj3. 650g of methane produces 32600 kj. Calculate the energy produced by 1.0

mole of methane and add this energy to the product side of the equation. ANS: 802 kj

4. Which reaction (coal or methane) releases the least carbon dioxide per kj of energy produced? HINT: Write the balanced chemical equation with the heat term.