CHE1210 Exam #1: Definitions

What's an isotope?

Atoms of the same element that have different numbers of neutrons.

How many protons, neutrons, and electrons are in:

18

O

8

8 protons, 8 electrons, 10 neutrons.

What's a pure substance?

A substance made from a single type of element or compound throughout its solution.

What's a mixture?

A combination of two or more substances that are not chemically combined in one solution.

What's the difference between a homogeneous and a heterogeneous mixture?

-A homogeneous mixture has the same properties throughout the sample. (Think of a coca-cola drink.)

- A heterogeneous mixture has different "layers" of properties throughout sample. (Think of a cake that has multiple layers of frosting.)

What's the difference between a physical and chemical change?

Physical change can change state of matter, but doesn't change chemical composition (ex. water --> ice)

Chemical change is a change that changes it's chemical composition (iron rusting)

What's a physical property?

A characteristic of a pure substance that can be observed without needing to change it to another substance (ex. boiling point)

What is a chemical property?

A characteristic of a substance that describes its ability to change into different substances (it's "reactivity)

What's the SI unit for length?

meter (m)

What's the SI unit for mass?

kilogram (kg)

What's the SI unit for volume and temperature?

Volume: m^3

Temperature: K (Kelvin)

What's the periodic table arranged by?

Increasing atomic # (Z)

What are the rows/columns called on the periodic table?

Rows are called periods, columns are called groups.

What are some properties of metals?

They have:

-Metallic luster

-Are malleable

-Very good conductors of heat/electricity

-Solid at room temperature

What are some properties of non-metals?

They are:

-Mostly gases (except Br2, liquid)

-They are brittle

-Not good conductors of electricity/heat

What are some properties of metalloids?

They:

-Can have metallic shine, but are brittle like non-metals

-Are semi-conductors, conduct electricity well, but not as good as metals

What are cations and anions?

Cations are positively charged ions that tend to lose electrons.

Anions are negatively charged ions that tend to gain electrons.

What's an ionic compound?

Metal + nonmetal (optional: conducts electricity in solid state)

What's a molecular compound?

Nonmetal + nonmetal (optional: does not conduct electricity in any state)

How much atoms are in one mole?

6.022 x 10^23 atoms per mole

What's a limiting reactant?

The compound that gets used up first of the two.

What's an excess reactant?

The compound that still has leftovers after the limiting reagent is used.

What's a solute v.s solvent?

Solute is the substance that gets dissolved in the solvent.

The solvent is the thing that dissolves the solute.

(salt dissolving in water, salt is the solute, water is the solvent).

What's an electrolye?

Strong electrolytes fully dissolve in water, and are normally good conductors of electricity.

What are examples of electrolytes?

Strong acids and bases, IONIC compounds.

What are weak electrolytes?

Weak electrolytes only partially dissolve in water and weakly conduct electricity.

What are examples of weak electrolytes?

Weak acids and bases.

What are acidic anhydrides?

Compounds that you can add water to to make the hydronium ion. (ex. SO3, and other oxyacids)

What are basic anhydrides?

Compounds that you can add water to make the hydroxide ion (OH-).

What are examples of basic anhydrides?

Grp1/Grp2 metal oxides (ex. MgO), and Ammonia (NH3)

What's a titrant?

It's typically the solution in the buret that you're about to pour in that has a known concentration.

What is an analyte?

It's the solution in the flask with an unknown concentration.

What is the equivalence point in a titration?

The equivalence point has been reached when the same number of moles of acid and base have been mixed.

What is a salt?

A salt is the ionic compound formed alongside water after an acid-base neutralization reaction.

What gas forms in a metathesis reaction with sulfide?

H₂Sⁿ

What gas forms in a methathesis reaction with cyanide?

HCNⁿ

What gas forms in a metathesis reaction with carbonates or bicarbonates?

CO₂

What gas forms in a metathesis reaction with sulfites or bisulfates?

SO₂

What gas forms in a metathesis reaction with ammonium salts (like NH4⁺)?

NH₃