Chemistry 8P11 - Elements, Compounds, Mixtures

Question 1

Define:

Substance

Answer 1

A substance is made from one type or different types of atoms, which combine with one another in various ways.

Question 2

Define:

Pure Substance

Answer 2

A pure substance is made from one type of atom, has predictable physical and chemical properties given STP conditions that can be used to identify it.

Question 3

Define:

Atom

Answer 3

An atom is the basic unti of matter; multiple atoms may be chemically bonded together to form molecules.

Question 4

Define:

Molecule

Answer 4

A molecule is a group of two or more atoms held together by chemical bonds, range in size from two to thousands of atoms.

Question 5

Define and give examples:

Diatomic Element

Answer 5

A diatomic element is formed by atoms that are chemically bonded in pairs. Ex: hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I)

Question 6

Define:

★Element

Answer 6

An element is a pure substance that cannot be broken down into simplier substances without changing the identity of the element.

Question 7

Define:

Isotope

Answer 7

Isotopes are different forms of an element (same number of p+), varying numbers of n⁰ (ex: C-14)

Question 8

Define:

★Compound

Answer 8

Compounds are made up of 2 or more types of elements chemically bonded in fixed proportions/ratios.

Question 9

Define:

“chemically-bonded”

Answer 9

To be chemically-bonded means two or more atoms have gained, lost or are sharing electrons.

Question 10

Define:

Chemical Formula

Answer 10

A chemical formula is the combination of chemical symbols and numbers used to represent a compound. The letters represent the type of atom (element) and the subscript numbers represent the quantity of atoms.

Question 11

Give the chemical formula for:

Glucose

Answer 11

C_₆H_₁₂O_₆

Question 12

Define:

★Mixture

Answer 12

A mixture is a combination of compounds and/or elements that can be physically separated. Mixtures can be heterogeneous or homogeneous.

Question 13

Define:

★Hetergeneous Mixture

Answer 13

A heterogenous mixture is one where the components are unevenly distributed, easily seen

examples of gases: ambient/atmospheric air

examples of solids: salad, granite, soil

examples of liquids: iced tea

Question 14

Define:

★Homogeneous Mixture

Answer 14

A homogeneous mixture is a mixture which has uniform composition and properties throughout. Solutions are types of homogeneous mixtures.

examples of solids: cement, bronze, steel, brass

examples of liquids: coffee, blood plasma, water, wine, salt water

Question 15

Define:

Solution

Answer 15

a homogeneous mixture

Question 16

Define:

Solute

Answer 16

the substance to be dissolved

Question 17

Define:

Solvent

Answer 17

the substance to do the dissolving

Question 18

Define:

Universal Solvent

Answer 18

water

Question 19

Define:

Concentration

Answer 19

how much solute is present in a solution compared to the amount of solvent

Question 20

Define:

Saturated Solution

Answer 20

contains solute at a concentration equal to its solubility

Question 21

Define:

Aqueous Solution (aq)

Answer 21

H₂O as the solvent

Question 22

Define:

pH

Answer 22

measure of acidity/basicity of a solution, scale from 0-14, closer to 0 – strong acid, closer to 14 – strong base, water is neutral at 7