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What is a pure substance?

A pure substance is a material made up of only one type of particle either an element or a compound

Define element and compound.

An element is a pure substance made of only one type of atom while a compound is a pure substance composed of two or more different elements chemically combined

What is a homogeneous mixture?

A homogeneous mixture is a mixture in which the composition is uniform throughout and the components are not visibly distinguishable

What is a heterogeneous mixture?

A heterogeneous mixture is a mixture where the components remain distinct and can be visibly identified

What is the difference between qualitative and quantitative observations?

Qualitative observations describe qualities using the senses while quantitative observations involve numerical measurements

Define physical property.

A physical property is a characteristic of matter that can be observed or measured without changing its chemical identity

Define chemical property.

A chemical property describes a substance's ability to undergo changes that transform it into different substances

What is a physical change?

A physical change affects the form of a substance but not its chemical composition

What is a chemical change?

A chemical change results in the formation of one or more new substances with different properties

What is density and how do you calculate it?

Density is the mass of a substance per unit volume calculated using the formula density equals mass divided by volume

How do you locate an element on the Periodic Table?

Elements are arranged by increasing atomic number with groups as vertical columns and periods as horizontal rows

What is the atomic number?

The atomic number is the number of protons in an atom's nucleus and also equals the number of electrons in a neutral atom

What is the mass number?

The mass number is the total number of protons and neutrons in the nucleus of an atom

Compare metals and non-metals.

Metals are shiny conductive and malleable while non-metals are dull brittle and poor conductors

Describe the alkali metals.

Alkali metals are in group one are highly reactive and are soft low density metals

Describe the alkaline earth metals.

These group two metals are reactive but less so than alkali metals and are harder and denser

Describe the halogens.

Halogens are group seventeen non-metals that are highly reactive and form salts with metals

Describe the noble gases.

Noble gases are group eighteen elements that are inert colorless and very stable

Who proposed the first atomic theory and what was it?

John Dalton proposed that atoms are solid indivisible spheres and that atoms combine in fixed ratios to form compounds

What was Thomson’s atomic model?

Thomson proposed the plum pudding model where electrons are embedded in a positively charged sphere

Describe Rutherford’s atomic model.

Rutherford discovered the nucleus and proposed that atoms have a small dense positively charged center with mostly empty space around it

What did Bohr contribute to atomic theory?

Bohr proposed that electrons orbit the nucleus in fixed energy levels and can move between levels by absorbing or emitting energy

What is standard atomic notation?

Standard atomic notation shows the element symbol with the atomic number at the bottom left and the mass number at the top left

How do you calculate the number of neutrons in an atom?

Subtract the atomic number from the mass number

What is the difference between atoms and ions?

Atoms are neutral with equal protons and electrons while ions are charged due to losing or gaining electrons

How do you draw Bohr-Rutherford diagrams?

Draw the nucleus with protons and neutrons and place electrons in shells following the pattern two then eight then eight

What is meant by counting atoms?

Counting atoms means identifying how many of each type of atom are in a chemical formula

What is the test for oxygen gas?

A glowing splint relights in the presence of oxygen

What is the test for hydrogen gas?

A burning splint makes a pop sound when hydrogen is present

What is the test for carbon dioxide?

Bubble the gas through limewater and it turns cloudy

How does static electricity form?

Static electricity forms when electrons are transferred between objects due to friction

State the law of electric charges.

Like charges repel and opposite charges attract

What is the difference between conductors and insulators?

Conductors let electrons flow easily while insulators resist the flow of electrons

Explain charging by friction.

Charging by friction happens when two materials are rubbed and electrons are transferred

What is conduction in charging?

Conduction transfers charge through direct contact

What is electric discharge?

Electric discharge is the sudden release of built up static electricity

Draw and label a simple electric circuit.

A circuit has a power source wires a load and a switch

What is electrical current I?

Current is the flow of electric charge measured in amperes

What is potential difference voltage?

Voltage is the energy per charge measured in volts

What are four factors that affect resistance?

Resistance is affected by wire length thickness temperature and material

State Ohm’s Law.

Ohm’s Law is voltage equals current times resistance

How do you calculate perfect efficiency?

Efficiency equals useful output energy divided by input energy times one hundred

Compare series and parallel circuits.

Series circuits have one path while parallel circuits have multiple paths

Give one analogy for series vs parallel circuits.

A series circuit is like a single lane road while a parallel circuit is like a multi lane highway

What are renewable and non-renewable energy sources?

Renewable sources like solar and wind are naturally replenished non-renewable sources like coal are finite

What are the four Earth spheres?

Biosphere atmosphere lithosphere and hydrosphere

Define biotic and abiotic factors.

Biotic factors are living and abiotic factors are non-living

Define individual population community and ecosystem.

An individual is one organism a population is a group of the same species a community includes all living things and an ecosystem includes both living and non-living parts

Compare photosynthesis and cellular respiration.

Photosynthesis uses carbon dioxide and water to make glucose and oxygen while cellular respiration breaks down glucose to release energy

What are producers consumers decomposers?

Producers make food consumers eat others and decomposers break down dead matter

What is the difference between food chains and food webs?

Food chains show one energy path food webs show many

Define herbivore carnivore and omnivore.

Herbivores eat plants carnivores eat meat omnivores eat both

What are ecological pyramids?

Ecological pyramids show energy biomass or number of organisms at each level

What are biotic and abiotic influences?

Biotic influences include living interactions abiotic influences include temperature sunlight and water

What is carrying capacity?

The maximum population size an ecosystem can support

Compare primary and secondary succession.

Primary succession starts with bare rock secondary starts with existing soil

Define ecological equilibrium.

A stable state where species and environment remain balanced

What is bioaccumulation?

The buildup of toxins in an organism over time

What is biomagnification?

The increase in toxin concentration at higher levels of the food chain

What are pesticides?

Chemicals used to kill pests that can also harm other species

How do human activities increase CO2 levels?

Burning fossil fuels and cutting trees add more carbon dioxide to the air

What are celestial objects?

Natural objects in space such as stars planets and moons

What is the structure of the Sun?

The Sun has a core radiative zone convective zone and outer layers like the photosphere

What is nuclear fusion?

A process where hydrogen atoms join to form helium releasing energy

How do we measure space distances?

Use kilometers astronomical units or light years depending on the distance

What causes day and year on Earth?

Earth's rotation causes day and its orbit causes a year

What is the difference between heliocentric and geocentric models?

Heliocentric means Sun centered geocentric means Earth centered

What causes seasons?

Earth's tilt makes different parts get different amounts of sunlight

What are solar and lunar eclipses?

A solar eclipse is when the Moon blocks the Sun a lunar eclipse is when Earth blocks the Moon

What are constellations?

Patterns of stars seen from Earth

What is the Big Bang Theory?

A theory that the universe began from a single point and has been expanding

What is red shift?

When light from galaxies shifts toward red showing they are moving away

What is a characteristic physical property?

A characteristic physical property is a quality that is unique to a substance and can be used to identify it such as density boiling point or melting point

How is density used to identify substances?

Different substances have different densities which are consistent at a given temperature and can be compared to known values

What are isotopes?

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons

How do you calculate atomic mass from isotopes?

Multiply each isotope’s mass by its relative abundance then add the results to get the average atomic mass

What is the electrostatic series?

A list of substances ranked by how likely they are to gain or lose electrons through friction

What happens during charging by induction?

A charged object brought near a neutral one causes electrons to shift without touching creating opposite charges

What is the purpose of a circuit breaker or fuse?

Circuit breakers and fuses stop current flow when too much electricity passes to prevent damage and fire

What is electric power and how is it calculated?

Electric power is the rate of doing electrical work and is calculated using power equals voltage times current

What is the difference between energy and power?

Energy is the total work done while power is how fast that energy is used

How does resistance affect current?

As resistance increases current decreases because resistance makes it harder for current to flow

How do you calculate resistance in a series circuit?

Add the resistors together to get the total resistance

How do you calculate resistance in a parallel circuit?

Use the formula one over total resistance equals one over each individual resistance

What is photosynthesis and its equation?

Photosynthesis is when plants use sunlight carbon dioxide and water to make glucose and oxygen

What is cellular respiration and its equation?

Cellular respiration breaks down glucose with oxygen to make energy carbon dioxide and water

Why are decomposers important in ecosystems?

Decomposers break down dead organisms and return nutrients to the soil

What are limiting factors in ecosystems?

Conditions like food temperature and space that limit how big a population can get

How do pesticides enter the food chain?

Pesticides can be taken in by producers and passed up through consumers

What is a trophic level?

A trophic level is a step in the food chain showing how energy moves from one group to another

What is ecological equilibrium and how is it maintained?

It is a stable ecosystem state where balance is kept by feedback competition and limits

What causes primary succession?

It happens when life starts in an area with no soil like after a volcanic eruption

What causes secondary succession?

It happens in areas where life existed before but was disturbed by something like fire or flood

What is the difference between bioaccumulation and biomagnification?

Bioaccumulation is toxin buildup in one organism biomagnification is toxin increase through the food chain

How do human activities increase greenhouse gases?

Burning fossil fuels deforestation and industry release gases like carbon dioxide and methane

What is the structure of the Milky Way?

The Milky Way is a spiral galaxy with a dense center and arms where our solar system is located

What is an asteroid belt?

A region between Mars and Jupiter where many rocky objects orbit the Sun

What is a meteoroid vs a meteor vs a meteorite?

A meteoroid is in space a meteor burns in the atmosphere and a meteorite reaches Earth

What causes a solar eclipse?

When the Moon passes between Earth and the Sun casting a shadow on Earth

What causes a lunar eclipse?

When Earth passes between the Sun and the Moon and its shadow falls on the Moon