A New Language

Chemical symbols, names

Chem catalystThere are 2 bottles on a shelf in a chemistry lab. Both

contain a shiny metal substance that resembles gold. Bottle A is labeled Au (s). Bottle B is labeled FeS2 (s)

Do you think both bottles contain gold? Explain your answer

What do you think the symbols on the bottles mean?

MAIN QUESTION

• What do the chemical symbols tell us about the substance in the bottle?

Unit 1 • Investigation II

You will be able to:

– Make sense of chemical names and symbols.

– An element is a unique form of matter that serves as a building material for more complex matter.

– Elements cannot be broken apart into two different substances.

– Chemical Formula are created from the symbols of elements

– A symbol for an element consist of 1-2 letters usually from the element’s name

Unit 1 • Investigation II

Element

Unit 1 • Investigation II

Activity

• Purpose: The goal of this lesson is to give you practice making sense of some of the “language” of chemistry, and translating chemical names and formulas.

(cont.)

Each person work on their own• Will copy and fill out the chart found on page 18 in

the text

• Each person starts with 1-2 vials, when your done, trade with others or Mr. Baker

• IF you can’t read Mr. Baker’s writing on the labels, ask him for clarification

• When you complete vials 1-17, see Mr. Baker about vial 18

Unit 1 • Investigation II

Name Chemical formula

Description

Vial 1

Vial 2 copper nitrate

Vial 3 blue-green crystals

Vial 4

Vial 5 NaNO3(s)

Vial 6

Vial 7

Vial 8

Vial 9 nitric acid

Unit 1 • Investigation II

Name Chemical formula

Description

Vial 10 fine, brown powder

Vial 11 NaOH(aq)

Vial 12

Vial 13

Vial 14 clear liquid

Vial 15 zinc sulfate

Vial 16

Vial 17 Cu(NO3)2(aq)

Vial 18

Unknown vial

• Get vial 18 from your teacher.

• Substances from 2 two vials have been mixed together in Vial 18

• Give the chemical symbols for the two substances

Get question handout

Questions on the questions 1-6

Compounds

• Are substances made up of more than one element.

• On the data table place a “C” next to the number of each vial that contains a compound.

Chemical Formulas

• Represent the makeup of compounds and molecules

• Subscripts indicate the ratio of elements in amount

• H2O , NaCl, C16H10N2O2

• All elements that make up a compound are listed in the name

Chemical formulas

A chemical formula is the set of symbols a chemist uses to represent a compound.

Carbon dioxide is a compound.

Its chemical formula is CO2.

Any amount of carbon dioxide has twice as much oxygen in it than carbon

Unit 1 • Investigation II

(cont.)

Compound

A compound is a substance that consists of two or more elements CHEMICALLY combined together in an exact and unvaried ratio of amounts of each element.

This ratio is described by a chemical formula, its “recipe”

Only compounds are described by chemical formulas

Mixture

• Composed of 2 or more elements or compounds that are PHYSICALLY put together

• Stirring• Dissolving

• No chemical reaction between parts• Usually not described by a chemical formula

Letters in parenthesis

• What do s, l, g, and aq stand for?

An Aqueous Solution

Is a substance is considered aqueous when it has been dissolved in water, creating a solution

Solution

Is a mixture of 2 or more elements or compounds combined in a physical matter.

Dissolving is a physical action not chemical.

No chemical reaction between objects

Parts of a solution

Solute: The elements or compounds being dissolved

Solvent: The material that the solute is being disolved in (the Water)

Compound or mixture

• Are aqueous solutions compounds or mixtures?

• Is the solute used in an aqueous solution a compound or mixture?

Compare NaOH (aq) and H2O (l)

• What are the similarities?

• What is the difference?

The difference between (aq) and (l)

• (l) is a liquid composed of a single compound, like water

• (aq) is a solution composed of a mixture of compounds

What do the subscript numbers mean?

Subscripts

• Indicate the “Parts” or equivalent amounts needed of each element to make a certain compound.

• The subscript indicates the amount of only the element immediately before it, unless in ()

• C16H10N2O2 means …

How many “pieces” of elements are required to produce a molecule of

H2SO4?

Unit 1 • Investigation II

Making Sense

– When you turned the penny silver on the first day of class, you used zinc, Zn(s), and sodium hydroxide, NaOH(aq). Do you think the penny was coated with silver, Ag(s)? Explain your reasoning.

Check in

• Imagine you find a vial that is labeled:

Na2SO4 (aq)

What does the label tell you about what is in the flask?

Wrap up• Chemical symbols represent the elements to combine to form

various substances

• Most symbols are either 1 or two letters, 2nd is always lowercase

• The chemical formula tells what elements are in the compound as well as the relative amounts

• Explain the relationship between elements, compounds, and mixtures