writing and balancing chemical equations (practice)

In level 1, you balanced the equation N2 + H2 → _NH3. What number did you place in front of ammonia (NH3)? 1 2 3 4

2

What is the chemical equation for the burning of propane if all the products and reactants are in the gas phase? 4H2O(g) + 3CO2(g) + 5O2(g) → C3H8(g) C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g) C3H8(g) + O10(g) → 3CO2(g) + 4H2O(l) 4H2O(l) + 3CO2(g) → C3H8(g) + 5O2(g)

C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(g)

In level 2, you balanced the equation C + H2O → CH4 + _CO2. What number did you place in front of carbon dioxide (CO2)? 1 2 3 4

1

solid sodium + chlorine gas → solid sodium chloride 1) aqueous hydrogen peroxide → oxygen gas + liquid water 2) 2Na(s) + Cl2(g) → 2NaCl(s) 3) hydrogen gas + oxygen gas → water gas 4) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

2) 2Na(s) + Cl2(g) -> 2NaCl (s)

Which equation obeys the law of conservation of mass? H2(g) + O2(g) → H2O(g) H2(g) + O2(g) → H2O(g) +4He(g) 2H2(g) + O2(g) → 2H2O(g) H2(g) → H2O(g) H2(g) + O2(g) → 2H2O(g)

2H2(g) + O2(g) -> 2H2O(g)

solid sodium + liquid water → aqueous sodium hydroxide + hydrogen gas 1) aqueous hydrogen peroxide → oxygen gas + liquid water 2) 2Na(s) + Cl2(g) → 2NaCl(s) 3) hydrogen gas + oxygen gas → water gas 4) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

4) 2Na(s) + 2H2O(l) -> 2NaOH(aq) +H2(g)

In level 3, you balanced the equation NH3 + O2 → NO2 + _H2O. What number did you place in front of water? 2 4 5 6

6

Barium chlorate (Ba(ClO3)2) breaks down to form barium chloride and oxygen. What is the balanced equation for this reaction? When counting atoms in parentheses, multiply all subscripts by the number outside the parentheses to get the number of atoms. BaCl3(s) + O2(g) → BaCl(s) + Cl2(g) + O2(g) 2BaOCl3(s) → 2BaCl(s) + Cl2(g) + O2(g) Ba(ClO3)2(s) → BaCl2(s) + O2(g) Ba(ClO3)2(s) → BaCl2(s) + 3O2(g) 2Ba(ClO3)2(s) → BaCl(s) + 6O2(g) Ba(ClO)2(s) → BaCl2(s) + O2(g)

Ba(ClO3)2(s) -> BaCl2(s) + 3O2(g)

Carbon dioxide and water are produced when pentane (C5H12) reacts with oxygen. What is the balanced equation for this reaction? C5H12(g) + O2(g) → CO2(g) + H2O(g) C5H12(g) + O2(g) → 5CO2(g) + H2O(g) C5H12(g) +8O2(g) → 5CO2(g) + 6H2O(g) 5CO2(g) + 6H2O(g) → C5H12(g) + 8O2(g) C5H12(g) +5O2(g) → 5CO2(g) + 6H2(g) CH2(g) +O2(g) → CO2(g) + H2(g)

C5H12(g) + 8O2(g) -> 5CO2(g) + 6H2O(g)

Mercury(II) oxide breaks down when it is heated to form oxygen gas and liquid mercury. oxygen gas + mercury → mercury(II) oxide mercury(II) oxide + oxygen → mercury mercury → mercury(II) oxide + oxygen mercury(II) oxide → oxygen + mercury

Mercury(II) oxide -> oxygen + mercury

Aqueous magnesium chloride and hydrogen gas are produced when solid magnesium reacts with aqueous hydrochloric acid (HCl). What is the equation for this reaction? Do not worry about balancing this equation. Mg(s) + HCl(aq) → MgCl(aq) + H(g) MgCl(aq) + H(g) → Mg(s) + HCl(aq) Mg(s) + HCl(aq) → MgCl2(aq) + H2(g) MgCl2(aq) + H2(g) → Mg(s) + HCl(aq) Mg(s) + HCl(aq) + H2(g) → MgCl(aq)

Mg(s) + HCl(aq) -> MgCl2(aq) + H2(g)

Sulfur trioxide is a gas that reacts with liquid water to produce aqueous sulfuric acid, or acid rain. What is the equation for this reaction? Do not worry about balancing the equation. SO3(g) + H2O(g) → H2SO4(g) SO3(g) + H2O(l) → H2SO4(aq) H2SO4(g) → SO3(g) + H2O(l) S3O(g) → H2SO4(s) + H2O(l) H2SO4(aq) + H2O(aq) → SO3(g)

SO3(g) + H2O(l) -> H2SO4(aq)

Propane burns in oxygen to produce carbon dioxide and water. What are the chemical formulas of the reactants and products? The formulas of the reactants are C3H8, O, and CO2. The formula of the product is H2O. The formulas of the reactants are C3H8 and O2. The formulas of the products are CO and H2O. The formulas of the reactants are C3H8 and O2. The formulas of the products are CO2 and H2O.

The formulas of the reactants are C3H8 and O2. The formulas of the products are CO2 and H20.

What do the symbols tell you about the conditions of the reactions shown to the right? Check all of the boxes that apply. The products and reactants of both reactions are gases. Reaction 1 occurs at high pressure. Reaction 2 makes a small amount of an additional product. A catalyst is used for reaction 2.

The products and reactants of both reactions are gases. A catalyst is used for reaction 2.

How do balanced chemical equations show the conservation of mass? They show that the atoms in the products may be different than the reactants as long as the mass does not change. They show that the atoms in the products are the same as in the reactants, but the number of atoms must change. They show that the number of atoms of each element is the same in the products and reactants.

They show that the number of atoms of each element is the same in the products and reactants.

2H2O2(aq) → O2(g) + 2H2O(l) 1) aqueous hydrogen peroxide → oxygen gas + liquid water 2) 2Na(s) + Cl2(g) → 2NaCl(s) 3) hydrogen gas + oxygen gas → water gas 4) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

aqueous hydrogen peroxide -> oxygen gas + liquid water

Calcium hydroxide and hydrogen gas are produced by the reaction of calcium hydride and water. calcium hydride + hydrogen → calcium hydroxide + water calcium hydride + water → calcium hydroxide + hydrogen calcium hydroxide + hydrogen → calcium hydride + water calcium hydroxide + water → calcium hydride + hydrogen

calcium hydride + water -> calcium hydroxide + hydrogen

When methane burns, it reacts with oxygen to produce water and carbon dioxide. The word equation that represents this reaction is: methane + oxygen -> hydrogen + oxygen gas + liquid carbon dioxide + water

carbon dioxide + water

Methanol (CH3OH) forms when carbon monoxide reacts with hydrogen. carbon monoxide + methanol → hydrogen methanol → carbon monoxide + hydrogen carbon monoxide + hydrogen → methanol methanol + hydrogen → carbon dioxide

carbon monoxide + hydrogen -> methanol

Electrolysis breaks down water to form hydrogen and oxygen gas. The word equation that represents this reaction is: water -> hydrogen + oxygen water + gas water

hydrogen + oxygen

2H2(g) + O2(g) → 2H2O(g) 1) aqueous hydrogen peroxide → oxygen gas + liquid water 2) 2Na(s) + Cl2(g) → 2NaCl(s) 3) hydrogen gas + oxygen gas → water gas 4) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

hydrogen gas + oxygen gas -> water gas

A bright light is produced when magnesium reacts with the oxygen in air to form magnesium oxide. The word equation that represents this reaction is: magnesium + oxygen -> magnesium magnesium oxide oxygen

magnesium oxide

When sulfuric acid reacts with sodium hydroxide, sodium sulfate and water form. sulfuric acid + sodium hydroxide → sodium sulfate + water sulfuric acid → sodium hydroxide + sodium sulfate + water sodium sulfate + water → sulfuric acid + sodium hydroxide sodium sulfate + sulfuric acid → sodium hydroxide + water

sulfuric acid + sodium hydroxide -> sodium sulfate + water

Identify the information that can be included in a chemical equation. Check all of the boxes that apply. how long the reaction takes to occur the states of the reactants and products the temperature and pressure at which the reaction was carried out the relative amounts of reactants and products the actual mass of product that is produced by the reaction the type of catalyst that is used to speed up the reaction whether the reaction can go in both directions

the states of the reactants and products the temperature and pressure at which the reaction was carried out the relative amounts of reactants and products the type of catalyst that is used to speed up the reaction whether the reaction can go in both directions