Chemistry
General 8th grade science
More General 8th grade science
elements and compounds
Space Science
100

is the type of change that happens when chemical bonds break and new bonds form

what is a chemical change?

100

they are chemicals that act as biological catalysts by speeding up reactions in living things 

what are enzymes?

100

is the type of plate boundary where the sea-floor spreading occurs 

what is divergent?

100

is a group of elements that does not form compounds with other elements

what are the noble gases?

100

is the element that comprises most of the mass of the sun

what is hydrogen?

200

is an example of a chemical change

what is burning something?

200

is the SI unit for force

what is Newton?

200

is the organelle where the cellular respiration takes place

what is the mitochondria?

200

is the maximum number of valence electrons that an element can have

what is 8?

200

is the tide with the least difference between consecutive low and high tides.

what is a neap tide?

300

is the only sure evidence for a chemical reaction

what is a new substance?

300

is the term used for describing a model of the universe in which Earth is at the center of the revolving planets and stars

what is geocentric?

300

is the moon phase in which a lunar eclipse happens

what is a full moon

300

is the most abundant metalloid in Earth's crust

what is silicon?

300

Is the number of waves that pass a given point in a certain amount of time.

what is  frequency?

400

the substances listed on the left side of a chemical equation

what are the reactants?

400

Earth's atmosphere is composed of about 78 percent of this element

what is nitrogen?

400

is an example of a greenhouse gas

what is carbon dioxide?

400

is the chemical formula for sodium oxide 

what is Na2O ?

400

They are loose collections of ice , dust , and small rocky particles whose orbits can be very long.

what is a comet?

500

it says : matter is not created or destroyed

what is the principle of conservation of mass?

500

it has the longest wavelength in the electromagnetic spectrum 

what is radio waves?

500

is the unit used to measure distance in space

what is an astronomical unit?

500

is the name of the compound with the following chemical formula: KF

what is potassium fluoride?

500

Term describing a model of the solar system in which Earth and the other planets revolve around the sun

what is heliocentric?

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