Wrting Chemical Equations

​Chemical Equations: Sentences for a Chemist

By Lan Vu

​Objective:

By the end of this lesson, you will be able to

• write a chemical equation given the description

• write the description given the chemical equation.

Multiple Choice

How do scientist represent a chemical reaction?

• A chemical formula.
• A molecular diagram.
• A reaction chart.
• A chemical equation.

Labelling

Label the chemical equation.

Drag labels to their correct position on the image

Products

Reactants

Yield sign

coefficient

subscript

Multiple Choice

What are reactants in a chemical reaction?

• Reactants are the energy released during a chemical reaction.
• Reactants are the products formed in a chemical reaction.
• Reactants are the catalysts that speed up a chemical reaction.
• Reactants are the starting substances in a chemical reaction.

Multiple Choice

What are the products in a chemical reactions?

• Products are the substances formed as a result of a chemical reaction.
• Products are the starting materials in a chemical reaction.
• Products are the catalysts used in a chemical reaction.
• Products are the energy released during a chemical reaction.

Multiple Choice

What is the arrow in a chemical equation mean?

• The arrow indicates a chemical bond.
• The arrow means 'yields' or 'produces'.
• The arrow shows the direction of heat flow.
• The arrow represents a catalyst in the reaction.

Multiple Choice

What does the coeffient in a chemical equation mean?

• The coefficient indicates the temperature of a reaction.
• The coefficient shows the color of the substances involved.
• The coefficient measures the pressure in a chemical reaction.
• The coefficient represents the number of moles of a substance in a chemical reaction.

Multiple Choice

What does the subscript behind a substance in a chemical equation mean?

• The subscript indicates the temperature of the reaction.
• The subscript shows the charge of the element.
• The subscript represents the number of atoms of an element in a molecule or the number of molecule.

• The subscript represents the phase of the substance.

​Physical State Symbols

Used to represent the state of matter that substance is in

• (s)

  • Solid

• (l)

  • liquid

• (g)

  • Gas

• (aq)

  • Aqueous- substance is dissolved in water

​Try this:

Write the chemical equation for this description.

2 molecules of hydrogen gas react with 1 molecule of oxygen gas to produce 2 molecules of liquid dihydrogen monoxide.

​Try this:

Write the chemical equation for this description.

2 molecules of hydrogen gas react with 1 molecule of oxygen gas to produce 2 molecules of liquid dihydrogen monoxide.

​2 H_2(g) + O_2(g) → 2 H₂O_(l)

​Try this:

​HCl_(aq) +    Ca(OH)_2 (aq) →    CaCl_2(s)  +   H₂O_(l)

​Write this chemical equations in words.

​Try this:

​2HCl_(aq) +    Ca(OH)_2 (aq) →    CaCl_2(s)  +   2H₂O_(l)

​Write this chemical equations in words.

​2 molecules of aqueous hydrogen chloride reacts with 1 molecule of aqueous calcium hydroxide to produce 1 molecule formula unit of calcium chloride solid and 2 molecules of liquid dihydrogen monixide