Chemistry

What are atoms?

Atoms are the building blocks of all matter, making up everything around us. They are the smallest part of any molecule or element.

What are the three main parts of an atom?

Protons, Neutrons, Electrons

Where are protons and neutrons located in an atom?

They are located in the nucleus at the center of the atom.

What is the charge of protons?

Protons are positively charged.

What is the charge of neutrons?

Neutrons are neutral; they have no charge.

What is the charge of electrons?

Electrons are negatively charged.

What keeps the parts of the atom together?

The opposite charges of protons and electrons attract each other, keeping the atom stable.

How do you calculate the number of subatomic particles?

Number of protons = atomic number. Number of electrons = number of protons. Number of neutrons = atomic mass number minus atomic number.

What is an element?

An element is made up of only one type of atom and cannot be broken down into simpler substances.

What are the three classifications of elements in the periodic table?

Metals, Non metals, Semi metals (Metalloids)

What characterizes metals?

Metals are characterized by high electrical and thermal conductivity, malleability, ductility, and light reflectivity.

What characterizes non metals?

Non metals are characterized by poor electrical/thermal conductivity, brittleness, dullness, and weakness.

What is the periodic table?

The periodic table is a grid structure that displays elements, organized by groups (vertical) and periods (horizontal).

How is the symbol of an element formatted?

The first letter of the symbol is capitalized, and if there is a second letter, it is lowercase. E.g., O for Oxygen, Na for Sodium.

What is the definition of a compound?

A compound is a substance formed when two or more elements are chemically bonded together.

What is water in terms of elements?

Water is a compound formed from oxygen and hydrogen.

What is the ratio of hydrogen to oxygen in water?

2:1

What are the properties of compounds compared to their component elements?

Compounds have different properties from the elements that form them.

What is an example of a compound?

Carbon Dioxide (CO2)

What is the ratio of carbon to oxygen in carbon dioxide?

1:2

What is the importance of compounds?

Compounds are building blocks of matter and crucial for living organisms.

What is a molecule?

A molecule is a group of 2 or more atoms, which can be of the same or different elements.

What holds atoms together in a molecule?

Chemical bonds hold atoms together.

What happens during a chemical reaction?

Atoms of different elements bond together to form compounds.

What is the ratio of elements in sulfuric acid (H2SO4)?

2:1:4 for hydrogen, sulfur, and oxygen respectively.

What is the ratio of elements in potassium permanganate (KMnO4)?

1:1:4 for potassium, manganese, and oxygen respectively.

What is the ratio of elements in sulfur dioxide (SO2)?

1:2 for sulfur and oxygen.

What are synthesis reactions?

Reactions that involve the breaking and joining of chemical bonds to build up molecules.

What are decomposition reactions?

Reactions that break a compound down into its elements.

What is electrolysis?

A type of decomposition reaction that uses electrical energy to split compounds into elements.

What are electrodes?

Metal ends in electrolysis that must be electrically conductive.

What happens to electrons during electrolysis?

Electrons flow from the positive electrode to the negative electrode.

What is thermal decomposition?

A decomposition reaction that uses heat to split a compound into its elements.

What is a chemical reaction?

A process where reactants transform to form new substances called products.

What is an example of a chemical reaction?

Mixing baking soda and vinegar.

What indicates a chemical reaction has occurred?

Visible color change, Bubbles form, Temperature change, Smell produced

What is the general equation for a chemical reaction?

Reactant + reactant → Product

What is the chemical equation for water formation?

O2 + 2H2 → 2H2O

What are the two types of chemical reactions?

Combination reactions, Decomposition reactions

What is produced when baking soda reacts with vinegar?

Sodium Acetate, Water, Carbon Dioxide

What are chemical reactions?

Processes where reactants transform into products.

What is a combination reaction?

When two or more substances combine to form a new compound.

What is a decomposition reaction?

When a compound breaks down into simpler substances.

What happens when baking soda and vinegar mix?

A decomposition reaction occurs, forming CO2 gas, water, and sodium acetate.

What is the particle model of matter?

All matter is made up of particles that explain properties and behavior.

What do particles in matter do?

They are in constant motion, influenced by temperature and state.

What are intermolecular forces?

Forces of attraction between particles, varying in strength.

How does heat affect particles?

It increases energy, causing particles to move apart and change phase.

What characterizes solid particles?

Packed closely, organized pattern, vibrate in fixed positions.

What characterizes liquid particles?

Loosely arranged, move faster, slide past each other.

What happens to particles when cooling a substance?

Energy decreases, particles slow down and come together.

What is the effect of adding heat to a substance?

Increases energy, causes expansion, and may change phase.

What is the arrangement of particles in a solid?

Particles are closely packed and vibrate in place.

How do particles in a liquid behave?

Particles slide past each other and are not held strongly together.

What happens to particles when a solid is heated?

Particles gain energy, move faster, and overcome attractions.

What is melting?

When a solid turns into a liquid due to added energy.

What is evaporation?

When a liquid turns into a gas due to added energy.

What occurs during condensation?

When a gas turns into a liquid as it cools down.

What is freezing?

When a liquid becomes a solid as it loses energy.

What is sublimation?

When a solid turns directly into a gas.

What is deposition?

When a gas turns directly into a solid.

What is diffusion?

Movement of particles from high concentration to low concentration.

How does temperature affect diffusion?

Higher temperatures increase particle speed and diffusion rate.

What is the effect of concentration gradient on diffusion?

A larger difference speeds up the rate of diffusion.

How does surface area influence diffusion?

Larger surface area allows more particles to diffuse quickly.

What is mass?

The amount of matter in an object.

What is volume?

The amount of space an object occupies. Measured in litres (l), millilitres (ml), cm³, dm³, m³.

How do you calculate volume?

Volume = Length x Breadth x Height (L x B x H).

What is density?

The number of particles packed in a substance. Density = Mass/Volume.

Which is denser: iron or wood?

Iron is denser than wood due to more particles packed into it.

How does density affect mass and volume?

Two substances can have the same volume but different mass due to density.

Calculate the density of a wood block (10 cm x 5 cm x 3 cm, 150 g).

Density = 150 g / (10 cm x 5 cm x 3 cm) = 1 g/cm³.

Find the mass of an object with density 0.8 g/cm³ and volume 125 cm³.

Mass = 0.8 g/cm³ x 125 cm³ = 100 g.

Find the volume of a substance with mass 60 g and density 4 g/cm³.

Volume = 60 g / 4 g/cm³ = 15 cm³.

Calculate the density of an irregular object (320 g, displaces 200 mL).

Density = 320 g / 200 mL = 1.6 g/mL.

Find the volume of a block with mass 850 g and density 2.5 g/cm³.

Volume = 850 g / 2.5 g/cm³ = 340 cm³.

Which state of matter is the densest?

Solids are the densest due to closely packed particles.

Why are liquids less dense than solids?

Particles in liquids are not as close together as in solids.

Why are gases the least dense?

Particles in gases are spread out and far apart.

What happens to particles when a substance is heated?

Particles move faster and spread further apart, causing expansion.

What happens to particles when a substance is cooled?

Particles move slower and are pulled closer together, causing contraction.

What happens to particles when they cool?

Particles move slower, Forces of attraction become stronger, Particles are pulled closer together, Substance shrinks

What causes gas pressure?

Gas particles collide with container walls, Force from collisions creates pressure

What is the structure of a carbon atom?

Nucleus: 6 Protons, 6 Neutrons.

Electrons: Surrounding the nucleus

What are the subatomic particles in Helium?

Proton (red), Neutron (blue), Electron (grey)

What is the structure of the nucleus in an atom?

Contains protons and neutrons

What is a Periodic Table used for?

To organize and display chemical elements based on atomic number and properties

What does the atomic number represent?

Number of protons in the nucleus

What are valence electrons?

Electrons in the outermost shell of an atom

What are the types of bonds in water and table salt?

Covalent bond (water), Ionic bond (table salt)

What is the reaction of hydrogen and oxygen to form water?

2H₂ + O₂ → 2H₂O

What types of molecules are there?

Compounds (e.g., water, ammonia), Single elements (e.g., helium, hydrogen)

What are the molecules of single elements?

Helium (He), Hydrogen (H₂), Oxygen (O₂), Chlorine (Cl₂), Sulfur (S₈)

What happens in a decomposition reaction?

One reactant breaks down into two or more products.

What is the molecular formula for ethane?

C₂H₆

What is the molecular formula for propane?

C₃H₈

What is the general form of a decomposition reaction?

AB → A + B

What is the decomposition of calcium hydroxide?

Ca(OH)₂ → CaO + H₂O

What are the types of solid structures?

Simple cubic, Body centered cubic, Face centered cubic

What happens when energy is removed from a gas?

It converts to a liquid.