Chemistry Flashcards
What are the two types of mixtures?
Mechanical mixture and solution
Particle theory of matter (kinetic molecular theory)
- All matter is made of tiny particles
- Each pure substance has it’s own type of molecules, which are different from those of other elements
- Particles attract each other
- Particles are always moving
- Particles at a higher temperature move faster on average
Mechanical mixture=
A substance that contains different types of particles that ARENT uniformly distributed
Solution
A substance with different types of particles that ARE uniformly distributed
A liquid solution is always…
Transparent
Physical property:
A characteristic of a substance that can be observed or measured
Qualitative physical property:
A characteristic of a substance that is observed or described without being measured or calculated
Qualitative mnemonic
COST LM
Quantitative physical property:
Properties that are measured or calculated. They’re represented by a number and unit
Quantitative mnemonic
Very Many Boys Sold Hard Candies Downtown
Solvent and solute
Solvent: a liquid capable of dissolving another substance
Solute: the substance that is being dissolved into another substance
Solvent is water
Aqueous solution
When do solids tend to be more soluble and gases tend to be less soluble?
Higher temperatures
Density depends on (2 things)
- How tightly packed the particles are
2. The mass of each particle
Density equation
D=m/V
Solid:
A state that maintains it’s shape and volume and does not flow.
Liquid:
A fluid that takes the shape of the container.
Gas:
A fluid that completely fills the container
Gas to liquid
Condensation
Solid to gas/ gas to solid
Sublimation
Bio accumulation
The buildup of toxic substances in the tissues of animals over time
Bio magnification
The accumulation of toxic substances in progressively higher concentrations towards the top of the food chain
What is DDT?
A synthetic pesticide that was used to eliminate insect borne disease and increase crop yields worldwide. Harmful to nature.
Common chemical reactions include:
Reactivity with water, oxygen, acids/bases
Stability:
The ability of a substance to remain unchanged. How easily a distance decomposes
Toxicity
The ability of a substance to cause harmful effects in plants and animals
What happens in a chemical change?
Atoms combine to form new molecules, or molecules break apart and their atoms combine to form different molecules
Evidence of a chemical change (4)
Colour change
A gas is produced
Energy is released or consumed (ie heat)
A precipitate is formed
3 standard tests for gases
Carbon dioxide (acid indicator or limewater test) Oxygen (a glowing splint combusts) Hydrogen (flaming splint makes a pop sound)
Model:
A visual, verbal, or mathematical representation of a scientific structure or process
In the early 1800s, john dalton ran an electric current through water (___) producing ___ and ___ gases. Particles must be ____ because they have different properties. The V of ___ was ____x the V of _____.
Electrolysis Hydrogen Oxygen Different Hydrogen 2 Oxygen
Dalton’s atomic theory (4)
All matter is made up of small particles called atoms
Atoms cannot be created, destroyed or divided
All atoms of the same element are identical in mass and size. The atoms of one element are different in mass and size from other types.
Compounds are created when atoms of different elements link together in definite proportions.
Gas discharge tubes are aka
Cathode ray tubes- CRTs
How do gases conduct electricity well?
In a sealed container at very low pressure
Crooked determination of the nature of cathode ray tubes (2 things)
- Shadows of solid cross and end opposite to cathode proved that rays were being produced by the cathode, and moved to the anode.
- He determined that rays were composed of matter when they made a windmill in the tube spin.
Thomsons discovery of electrons
Oppositely charged plates on either side of a cathode ray. Particles veered towards the positive plates, therefore they were negatively charged: electrons.
Thomsons atomic model
Using different metals proved all electrons are the same.
If atoms are neutral and contain electrons, there must be positive material.
Created the raisin bun model. Raisins were electrons, dough was positive matter.
What did Neils Bohr (Danis, 1913) explain? What is his reasoning?
negative electrons in an atom don’t fall into the positive nucleus and stick to it because they’re moving so fast.
Spectroscopes
Shortest wavelength=highest energy= _____
Longest wavelength= lowest energy= _____
Violet
Red
What did Bohr observe about gas discharge tubes?
They produced thin lines of light. Each colour has a specific amount of energy.
Bohr’s Conclusions (3 things)
An electron orbits the nucleus with a specific amount of energy
To move between energy levels an electron must absorb/release a specific amount of energy called a “quantum”
The region in which an electron orbits is called an electron shell/orbital. Higher energy shells are farther from the nucleus
What are isotopes?
Versions of atoms of particular elements that have the same number of protons but different numbers of neutrons as other isotpes of that element.
Isotopes of one element have (2 things)
Identical chemical reactions
Some different physical properties
How did Dimitri Mendeleev develop the periodic table? (3 things)
He spotted a pattern when he placed elements in order of increasing atomic mass. His table showed that the properties of elements repeated periodically. He left gaps for undiscovered elements and could predict their properties.
What 5 pieces of information are shown in an element box?
Name Symbol Atomic Number Atomic Mass Ion Charge(s)
What is a period, and what do they all have in common?
A horizontal row of elements in the periodic table. Same number of shells.
What is a group/family and what do they have in common?
A vertical column of elements in the periodic table. They have the same number of valence electrons, except NOBLE GASSES have all full shells.
4 groups in the periodic table with numbers
Alkali metals (1), alkaline-earth metals (2), halogens (17), noble gasses (18)
Ion:
A charged atom (or group of atoms)
What happens in an ionic compound?
Electrons are transferred from metals to non-metals (study bohr diagram)
Explain the structure, state at room temperature, solubility, and conductivity of ionic compounds.
crystal lattice, solid, most are water-soluble, poor when solid, good when dissolved in water.
What is an ion charge?
The electrical charge an atom will acquire in its ion form, after electrons have been added or removed to achieve a stable octet or duet.
What is crystal lattice?
A regular repeating pattern of ions
How do you name ionic compounds?
- Name metal ion first.
2. Name non-metal second, add “ide”
Summary of a molecular (covalent) bond:
A link in which electrons are shared. They form between non-metal atoms and other non-metal atoms.
How are covalent bond bohr diagrams drawn?
With valence shells overlapping and only valence electrons shown.
How do you name covalent compounds?
Use greek prefixes: mono (not before first element), di, tri, tetra, penta.
Explain these about covalent compounds: Strength of attractions between molecules, structure, melting/boiling point, conductivity.
Weak, individual molecules, low compared to ionic compounds, poor conductors because their valence electrons are “tied up” bonds
Metals, Nonmetals, and metalloids
Metal: An element that is hard, shiny, malleable, ductile and a good conductor.
Non-metal: Not hard, shiny malleable, ductile and a bad conductor.
Metalloid: Shares some properties with metals and some with non-metals.
What is a polymer, and what is made out of them?
A giant molecule made of many repeating identical or very similar subunits (monomers) linked together by strong covalent bonds. Plastics.
