In an experiment involving the study of the reactivities of Group 1A elements with water, a small piece of potassium metal is added to water. Identify the reactants and products along with their physical states from the following observed chemical reaction. 

2 K, Potassium (s) + 2 H₂O, Water (l) → 2 KOH, Potassium hydroxide (aq) + H₂, Hydrogen (g)

A small amount of octane (a volatile liquid and a component of gasoline) is put into a sealed container that has a spark system fitted into it. The container is filled with excess oxygen and then sealed. When the spark system is turned on, the liquid inside starts burning. Does burning change the mass of the contents inside the container?

In the molecular diagram below, the blue spheres represent nitrogen atoms, while the white spheres represent hydrogen atoms. Give the balanced equation for the reaction. Note that all the molecules are gases.

Balance the equations below by adding the correct coefficients:

_{_____} CuO + _____ CO → _____ Cu + _____ CO₂

____ Na₃N + ____ H₂O → ____ NaOH + ____ NH₃

____ SeO₂ + ____ O₂ → ____ SeO₃

Consider the following chemical reactions with compounds written in words instead of chemical formulas. Write the balanced equations for these reactions using chemical formulas and all the physical states.

A) sodium + chlorine → sodium chloride

B) calcium hydride + hydrochloric acid → calcium chloride + hydrogen

C) carbon monoxide + oxygen → carbon dioxide

D) magnesium oxide + sulfuric acid → magnesium sulfate + water

E) sulfur + fluorine → sulfur hexafluoride

Identify all the soluble compounds:

a) magnesium chlorate                                            d) lead (II) nitrate

b) copper (II) hydroxide                                           e) barium carbonate

c) copper (II) sulfate                                                 f) silver bromide

Identify the ions in a solution where MgSO₄ is dissolved in water.

Dextromethorphan is in the form of dextromethorphan hydrobromide (DXM•HBr) when sold as an over-the-counter cold and cough medicine. What does HBr stand for? What type of reaction is necessary to convert DXM to the HBr form and what is the purpose of converting the drug to this form?

Identify the products of a double displacement reaction between calcium nitrate and potassium sulfide.

a) CaS and KNO₂

b) CaSO₃ and KNO₃

c) CaSO₃ and KNO₃

d) CaS and KNO₃

e) K₂SO₃, CaS and H₂O

f) None of the above

The blue spheres are sulfur atoms, the orange spheres are oxygen atoms, and the molecules involved are gases in the reaction below. Identify the reaction type.

Copper metal can be extracted from copper (II) oxide by displacing it with aluminum. This process is also known as the thermite reaction. Copper in copper (II) oxide will be reduced while aluminum will be oxidized, forming copper metal and aluminum oxide.  Provide the balanced equation for this reaction.

Balance the following reaction equations and determine the type of the reaction occurring:

i) ____ KCl + ____ H₃PO₄ → ___ K₃PO₄ + ___ HCl

ii) ___ Ca(OH)₂ + ___ Fe₂(CrO₄)₃ → ___CaCrO₄ + __ Fe(OH)₃