Science and Technology - Chapters 1 & 2 Flashcards

Flashcards based on Science and Technology lecture notes for 2nd secondary level, covering topics from Chapters 1 and 2, including atoms, elements, periodic table, molecules, mass volume, physical and chemical changes, conservation of matter, mixtures, and separation techniques.

What are the three states of matter?

Solid, liquid, and gaseous.

Who gave the name 'atomos' to the smallest particle of matter?

Democritus, a Greek philosopher.

According to Democritus, what are the properties of atoms?

Indivisible, indestructible, and in motion. They also compose different substances based on their shape and mass.

What did Aristotle believe about atoms and the division of matter?

Atoms don't exist, there is no void, matter is continuous and can be divided infinitely.

What are the four fundamental elements according to Aristotle?

Fire, water, air, and earth.

List five characteristics of Dalton's atomic model.

1- Matter is made of indivisible atoms too small to be visible. 2- Atoms of the same element are identical in mass and properties. 3- Atoms of different elements differ in mass and properties. 4- It is impossible to transform an element chemically into another. 5- Atoms can unite to form molecules.

What is Dalton's atomic model representation called?

The billiard ball model.

What are the charged particles that compose atoms?

Protons (+), electrons (-), and neutrons.

What is the electric charge of an atom?

Neutral. It has an equal number of protons and electrons.

Define an element.

A pure substance that cannot be chemically separated into other substances and comprises only one type of atom.

How are elements arranged in the periodic table?

By increasing order of atomic number.

What information is provided in each element's box in the periodic table?

Name of the element, atomic number, relative atomic mass, and symbol.

Define a molecule.

An assembly of at least two atoms, identical or different, united by chemical bonds.

How are molecules designated?

By a chemical formula, using element symbols and subscripts to indicate the number of atoms of each element.

What does the coefficient in front of a chemical formula indicate?

The number of molecules of that type present.

Give an example of a molecule along with the breakdown

2 NH4. 2: number of molecules, N: atom of nitrogen, H: atom of hydrogen, 4: number of hydrogen

Can molecules be divided?

Yes, through chemical reactions.

Define mass volume (masse volumique).

A unitary rate representing the mass of an object that occupies a volume of one milliliter.

For what situation does a mineral float on water?

When the mass volume of a mineral is less than 1.00 g/ml, it floats on water.

What is the formula for calculating the mass volume (masse volumique)?

ρ = mass/volume or ρ = m/V

What are the two types of transformations in matter?

Physical changes and chemical changes.

Define a physical change.

A transformation that does not change the nature or characteristic properties of a substance. The molecules remain the same before and after.

Name three categories of physical changes.

Change of state, change of form, and preparation or separation of a mixture.

Are properties generally conserved during a physical change?

Yes, the properties of substances are generally conserved.

Define a chemical change.

A transformation that changes the nature and characteristic properties of a substance, producing new substances with new properties.

What happens to the bonds between atoms during a chemical change?

The bonds are broken and atoms combine in a different way, resulting in a new substance.

List some indicators of chemical changes.

Significant color change, formation of a precipitate, release or absorption of heat, release of light, and release of a gas or effervescence.

What is the reaction called between a substance and oxygen that releases a lot of heat?

Combustion.

State the law of conservation of matter.

Nothing is lost, nothing is created, everything is transformed.

What two aspects does the law of conservation of matter encompass?

Conservation of mass and conservation of atoms.

Define a mixture.

An association of two or more substances.

What are the two types of mixtures?

Heterogeneous and homogeneous.

Define a heterogeneous mixture.

A mixture composed of at least two substances where the particles are not uniformly distributed, with at least two visible phases.

Define a homogeneous mixture.

A mixture composed of at least two substances whose constituents are uniformly distributed, with only one visible phase.

Define a solution.

A homogeneous mixture in which a solute is dissolved in a solvent.

What is the most common solvent?

Water.

List methods of separating a heterogeneous mixture.

Filtration, sieving, decantation or sedimentation, centrifugation, and magnetism.

List methods of separating a homogeneous mixture.

Evaporation and distillation.

What separation process transforms the liquid part of a mixture into gas?

Evaporation